# Conversion BMW Z3 which motor fits best?



## somanywelps (Jan 25, 2012)

People used 11"ers.


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## Elegancec (May 23, 2012)

Hi,

thank you for your post.

You're right, that would be the easiest conversion, but I think in Europe it would not be accepted from everybody.
In my opinon I have to use the energy from regenerative braking, because of the little capacity from the battery system.
So an Sepex or better AC system would ideally fit. The components I have suggested seem for me to be the best for this project.


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## somanywelps (Jan 25, 2012)

Sepex and AC are limited on the options, specifically power.

How many HP and nm did you want?

I don't think you're going to want to pay that much for regen.


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## steven4601 (Nov 11, 2010)

A Z3, brilliant choice if I may say so! 

If im not mistaken, an isolation test is carried out during type approval. If you use a virgen dc motor (no dust etc) you'll probably pass the isolation tests. However, if you use a motor that has some miles on it, it is likely to fail the isolation tests. (Isolation of 200 Ohm per Volt is required. 2mA leakage maximum). The 100-ohm per volt requirement usese battery voltage. Example: a 220 Volt pack would require 220kOhm isolation or better between the traction pack and chassis. 

If the dc / sepex motor is new, it will pass the isolation test. Otherwise it will be very doubtfull.


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## somanywelps (Jan 25, 2012)

zsnemeth said:


> 5900+3700= 9600 Euro
> 
> 11" Kostov Alpha 2200 Euro
> 
> ...


The alpha would be a good choice due to the forced air cooling:

295A 500A
100nm 194nm
0.4585365853658537x + -35.26829268292684

312ft*lb per 1 @1000A
624ft*lb per 2 @1000A
177ft*lb per 1 @600A
354ft*lb per 2 @600A
143ft*lb per 1 @500A
286ft*lb per 2 @500A


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## Elegancec (May 23, 2012)

Hello, thank you for your answers!

I think in comparison to the price and performance, there is no way not to use a DC system. So I have a question to the kostov 11 Alpha motor.
You can read on the controller homepages from netgain or zilla 1000A or also 2000A. So this is the maximum amperage rating what the controller can deliver.
If I look at the chart from the motor, round about 680A ->280Nm. So I think this is what somanywelps also stated in his previous mail.
So at 1000A -> 312ft*lb = 422Nm. I think the BMW would fly with this  So my next step is to clearify how much torque the gearbox can handle.

Attached the interpolation.


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## somanywelps (Jan 25, 2012)

Elegancec said:


> Hello, thank you for your answers!
> 
> I think in comparison to the price and performance, there is no way not to use a DC system. So I have a question to the kostov 11 Alpha motor.
> You can read on the controller homepages from netgain or zilla 1000A or also 2000A. So this is the maximum amperage rating what the controller can deliver.
> ...


Yes it would fly, I'm working on planning an E46 conversion.

The gearbox torque rating is a potential problem. Valerun has been running his E46 conversions with the stock, 300nm rated gearboxes at 484 nm out of a Warp 11HV at 1000A from a Soliton 1 without any issues except the clutch (he stated the stock ones slipped, not sure what he replaced it with).

BMW transmissions have a reputation for being strong, and even BMW runs them over "spec" (see E39 M5 with an S6S-420G transmission).

A cursory look at realoem shows the 2.5 and up Z3's as having a 320nm rated gearbox, and you'd be peaking at 427nm (K11A @1000A with Soliton 1), so you'll be fine (I think).

You may need to replace the clutch with something that can hold on against that much instant torque.


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## Elegancec (May 23, 2012)

Question about Solution 1 controller:

The website states 9-340V DC output. 
The Kostov 11 Alpha wants 240V. So in my opinion the controller makes a pwm signal of it. So the battery system has to provide 250V, is this correct? So its not possible to use an 100V battery pack as an example?


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## efan (Aug 27, 2009)

this controller+motor seem to be a new development, and I dont know of anyone who has used it..but it may be worth checking them out.

http://shop.greenstage.co.nz/product/100kw-scott-drive-ac-inverter-and-motor-package


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## njloof (Nov 21, 2011)

Elegancec said:


> Question about Solution 1 controller:
> 
> The website states 9-340V DC output.
> The Kostov 11 Alpha wants 240V. So in my opinion the controller makes a pwm signal of it. So the battery system has to provide 250V, is this correct? So its not possible to use an 100V battery pack as an example?


You can certainly drive the Kostov with 100V, but your max RPM will be severely limited. Even if your battery system is rated at 250V, it will sag below 240V under load. Better to target 300V, the controller's pwm will limit to 240V if you instruct it to never exceed this voltage.


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## somanywelps (Jan 25, 2012)

Elegancec said:


> Question about Solution 1 controller:
> 
> The website states 9-340V DC output.
> The Kostov 11 Alpha wants 240V. So in my opinion the controller makes a pwm signal of it. So the battery system has to provide 250V, is this correct? So its not possible to use an 100V battery pack as an example?


The K11A is rated 250V. You're going to want to be sitting with a nominal of above 300V depending on the total kwh of the pack and the peak amperage draw. 

No, 100V would be bad.


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## njloof (Nov 21, 2011)

efan said:


> this controller+motor seem to be a new development, and I dont know of anyone who has used it..but it may be worth checking them out.
> 
> http://shop.greenstage.co.nz/product/100kw-scott-drive-ac-inverter-and-motor-package


Wow -- that deserves its own thread!


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## albo2 (Oct 4, 2011)

There is also this


http://www.ev-power.com.au/-95-EV-Motors-AC-Induction-.html


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## Elegancec (May 23, 2012)

Hello, this motor is too small, only 120Nm at 3000rpm this is 100km/h or 65mph.


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## marc02228 (Jan 15, 2011)

Hi Elegancec, 

where are you from? I thought about the K11" alpha and soliton 1 in a Z3, too. But decided to put that stuff in a Miata due to the weight.


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## Elegancec (May 23, 2012)

Hello Marc, Im from Germany, near Kiel.

At the moment I can not see another solution as the kostov motor as useful.
On next monday I have a date with our transport of ministry to make a check list.

The BLDC Motor from Scott has negative effects like noise and vibration and low efficiency at low speeds - I do not have a diagram or values for this until now. Also there is no EMV / EMC document available up to now. This could be a problem with the transport of ministry.

The kostov engine can be bought in the EU, so I would save the taxes for import.


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## ruckus (Apr 15, 2009)

efan said:


> this controller+motor seem to be a new development, and I dont know of anyone who has used it..but it may be worth checking them out.
> 
> http://shop.greenstage.co.nz/product/100kw-scott-drive-ac-inverter-and-motor-package


Actually, for the $$$ you will spend on a failure-prone brushed dc motor you should consider a system without the Achilles heel. About the same price for a lot more performance.


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## somanywelps (Jan 25, 2012)

ruckus said:


> Actually, for the $$$ you will spend on a failure-prone brushed dc motor you should consider a system without the Achilles heel. About the same price for a lot more performance.


The BLDCs don't have the performance and certainly don't have the price performance.

Also he linked to a BLDC, but there was some discussion about that motor/controller and not in a positive light.


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## ruckus (Apr 15, 2009)

somanywelps said:


> The BLDCs don't have the performance and certainly don't have the price performance.
> 
> Also he linked to a BLDC, but there was some discussion about that motor/controller and not in a positive light.


Sorry, my post was confusing. I was trying to suggest he check out the Scott Drive system. It is the brushes that are the problem. They are failing left and right.

Where is there a discussion of the Scott system having problems? I would be interested in reading the issues.

I am confused that you say BLDC don't have performance because they nicely whip Brushed motors in power to weight ratio. Why do you think all the auto manufacturers use brushless motors? (both dc and ac, but ALWAYS brushless)

Show me a brushed motor and I will show you a brushless motor which weighs less and puts out more torque and more hp.

Powertec has some decent specs posted:
Their E215E2 motor weighs 211 pounds With the blower. Less than a Warp 11.
It produces 500ft lbs of torque from 0-2000+ rpm and has a max of 86hp CONTINUOUS at 3600rpm and 95hp at 5000rpm.

A Warp 11 is only rated at about 35hp continuous.

There is no comparison in terms of power and reliability. That is why industry has switched over.


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## somanywelps (Jan 25, 2012)

ruckus said:


> Sorry, my post was confusing. I was trying to suggest he check out the Scott Drive system. It is the brushes that are the problem. They are failing left and right.
> 
> Where is there a discussion of the Scott system having problems? I would be interested in reading the issues.
> 
> ...


1) COST

2) PEAK POWER (These are not race cars, they are street sport cars or dragsters)

3) COST per unit of performance.

(Also you can force air cool and do some other stuff. A Kostov 11" Alpha ($2700) is rated for 50kw continuous and puts out MONSTER torque compared to a BLDC. BLDCs do NOT overload well)


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## Elegancec (May 23, 2012)

I think BLDCs have only 2 servere issues:

They need the seltene Erden - neobdynmagnetics - I do not know if I wrote correctly.
And if the magnets will be too warm, they will loss there magnetic field. For trial and error its to fragile. But if everything is matching and the parameters for operation are clear and the cooling is guaranteed and they have a vector control, than they are state of the art also in there weight / performance ratio.

The Scott system has maybe one issue: The EMC from the switching and the vibrations. But it can only be marked in a test.


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## ruckus (Apr 15, 2009)

somanywelps said:


> 1) COST
> 
> 2) PEAK POWER (These are not race cars, they are street sport cars or dragsters)
> 
> ...


1) cost ... Well, lets just look at the numbers shall we? How about a cost comparison?
Using the Kostov 11 you say is $2700, add $3150 for a Solitron 1, add $130-200 for a contactor, How much for 4 10amp 12v circuits? Lets pretend that is only $100. So you are OVER $6000!!  plus, you had to house and wire the contactors and auxiliary power circuits and pay shipping on all the individual components. hmmm..

OR, you could spec the Scott Drive for only $5495. It has all that stuff on the inside. Did you realize that is the price WITH the motor?

2) not sure what you are saying here. Please elaborate.

3) Cost per unit of performance is LOWER for BLDC than any other motor type. Maybe it is just because I live in MT and we have to cross very steep and long passes, but a high continuous hp is the ONLY thing that will allow you to do this. Otherwise you will be on the side of the road with the VW busses... Overheated and broke down 

If you google Neodymium you will find this "rare" earth material is actually extremely common and easily produced. Not a problem at all. 

Cheers 

Sorry- forgot to talk about "monster" torque.
The Powertec E215 is 211 lbs and puts out 500 ft lbs. Not sure what you mean by "monster", but that doesn't seem all that shabby.


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## ElectriCar (Jun 15, 2008)

Solitons have the contactors built in also. And you can get them a few hundred dollars less than what you said so you're being misleading in more ways than one.


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## ruckus (Apr 15, 2009)

Not trying to be "misleading". Just quoted the price off EVSource which I thought was sort of "standard" prices.

Thanks for catching the contactor is included on the Solitron. My bad. Even so, the price of the BLDC motor is not crazy expensive like he is pretending. At best it is cheaper, at worst it is competitive in price. If you spec a Netgain instead of a Kostov then it is Definitely cheaper.

Brushed DC motors have become like bms vs no bms. More of a religion than a fact-based reality.

Many folks on this forum are financially linked to brushed motors continuing to sell despite their high failure rate. I have no allegiance other than searching for a reliable and affordable solution. I have tried brushed motors and have been disappointed. I want others to be aware of the reality and investigate the number of failures instead of blindly believing they are "reliable".

I believe it is best for the EV movement if our products are actually reliable. Otherwise our credibility is nill and there will be a backlash. 

Cheers.


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## somanywelps (Jan 25, 2012)

ruckus said:


> Thanks for catching the contactor is included on the Solitron. My bad. Even so, the price of the BLDC motor is not crazy expensive like he is pretending. At best it is cheaper, at worst it is competitive in price.


No. That's a ~300kw peak, ~310ft*lb peak arrangement. You're comparing it a 100kw peak arrangement that no one's tested. Also Tesseract pointed out some issues with the wave generation from the controller (basically the torque is gonna suck). 

A 132kw peak Brushed DC would be a $1700 Kostov 9" 220V motor and a $2000 soliton Jr. (6800rpm nominal, wide powerband) 

You could even step down to near 80kw with a $700 kelly and $1300 kostov 9" 



ruckus said:


> If you spec a Netgain instead of a Kostov then it is Definitely cheaper.


 No. Kostovs are cheaper.


ruckus said:


> Brushed DC motors have become like bms vs no bms. More of a religion than a fact-based reality.


 No. They're more cost effective for independent builders. 


ruckus said:


> Many folks on this forum are financially linked to brushed motors continuing to sell despite their high failure rate.


 No they don't have a high failure rate unless you're overloading them to shit for drag racing.


ruckus said:


> I have no allegiance other than searching for a reliable and affordable solution. I have tried brushed motors and have been disappointed. I want others to be aware of the reality and investigate the number of failures instead of blindly believing they are "reliable".


 No. They are reliable with reasonable overload.


ruckus said:


> I believe it is best for the EV movement if our products are actually reliable. Otherwise our credibility is nill and there will be a backlash.
> 
> Cheers.


 No. They are reliable with reasonable overload, they even have rated overloads. 

Cite where EV-intended brushed DC (not the china crap) are unreliable


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## ruckus (Apr 15, 2009)

somanywelps said:


> Cite where EV-intended brushed DC (not the china crap) are unreliable


I'll cut to the chase instead of arguing misunderstandings or minutia. (which there are plenty in your post)

Your claim that Brushed motors are reliable and are only failing under abuse is not supportable by the experiences of many people.

I will list just a few of the recent well-documented failures under normal use.

Tim Catellier had 2 Netgain failures with barely any miles. He is on #3.
Jack Rickard had 1 Netgain failure out of 3 motors used. Low mile failure.
SBJohnston had a FB1-4001 complete brush failure. Look at the pics:
http://www.diyelectriccar.com/forums/showthread.php/amd-fb1-4001-motor-failure-73628.html
DavidDymaxion "blew" the brushes in his Kostov. 
Here is another blog with a blown 9" motor well documented:
http://www.saturn.lynnautorepair.com/Advanced DC replaced with WarP 9 Netgain
These stories are common. Do you have Google there?

Just by bringing up this issue I have people PM'ing me to share more of the same. They don't want to post due to the amount of backlash that they are seeing aimed at those who come forward and tell the truth.

My goal is to see these issues resolved and to have EV's be reliable and awesome. If the EV movement gains power only to have lots of motors failing that will be a major setback. 

Why are you defending brushed motor failures? What do you have at stake? I gain nothing but ridicule by bringing up this unpopular topic.


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## efan (Aug 27, 2009)

somanywelps said:


> No. That's a ~300kw peak, ~310ft*lb peak arrangement. You're comparing it a 100kw peak arrangement that no one's tested. Also Tesseract pointed out some issues with the wave generation from the controller (basically the torque is gonna suck).
> 
> A 132kw peak Brushed DC would be a $1700 Kostov 9" 220V motor and a $2000 soliton Jr. (6800rpm nominal, wide powerband)
> 
> You could even step down to near 80kw with a $700 kelly and $1300 kostov 9"


There is no point of talking about price. Although there are some quality conversion components both DC and 3-phase AC they are all overpriced for their purpose. When you put together a decent DC motor, controller, charger, a battery pack and a vehicle that you would have no issue being seen in, you are at a price point where you can purchase a used Leaf or a Volt.


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## ruckus (Apr 15, 2009)

efan said:


> There is no point of talking about price. Although there are some quality conversion components both DC and 3-phase AC they are all overpriced for their purpose. When you put together a decent DC motor, controller, charger, a battery pack and a vehicle that you would have no issue being seen in, you are at a price point where you can purchase a used Leaf or a Volt.


Ha Ha, that is funny. A USED Leaf or Volt. You crack me up. They are just starting to think about releasing them in my state (MT).

You are right though, it isn't exactly FREE to build a custom car. But when was it ever?

Drive...5500
Batt....8000
Charge..500
misc...1000
--------------
Total... 15,000 PLUS car (1-5000). Not even close to $30000+ for a Leaf.

If you want to save money there are lots deals on Ebay. Or heck, order some magnets and a spool of wire and get to winding...


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## somanywelps (Jan 25, 2012)

ruckus said:


> I'll cut to the chase instead of arguing misunderstandings or minutia. (which there are plenty in your post)
> 
> Your claim that Brushed motors are reliable and are only failing under abuse is not supportable by the experiences of many people.
> 
> ...



The second ADC was clearly overheated (operator fault). There's not enough information on the first one, but they aren't very good and no one here recommends them. 

I would hardly consider ADC motors high quality, but do you have links to where the netgains/kostovs died and what they were running them at?


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## ruckus (Apr 15, 2009)

It is fun trying to keep up with you on the forum. You are a fast.

You can nit-pick the list if you want, but that is the tip of the iceberg. Don't assume heat-related failures are operator fault. If the motor is having brush issues it will cause extreme heat even at low power output. I have personally seen this. I gave you enough links and instances. If you bother to google you will find many more. You can also look in Evabum at higher mile EV's. The number of brush failures that take out the motor are fairly common.

You wanted Netgain failures and the first 3 on the list are Netgain. Funny you act like ADC are total junk. There is very little substantial difference between the two. On EValbum there are 270 Netgain and 757 ADC. Kostov has an impressive 44. 

While there are certainly an unacceptable amount of low-mile failures, it is normal for brush failures to increase with age. So ADC are deemed more failure-prone just because they are one of the few older motors. When Netgain and Kostov get a few years on them the same thing will happen. 

It wasn't long ago that it was difficult to convince anybody that Lithium batteries were better than lead. Eventually they actually tried them and found it to be true. Right now the brushed motors are "in" but the problems are starting to become difficult to ignore. Mention another motor type and you get shouted out of the forum. But it is like lead batts. Shouting can't cover up the truth. (I'm not saying you are doing that, I'm saying that is the feeling I get on the forum)

I am just wanting a reliable drive system that I would feel good giving to my grandmother. That is what EV's need to become mainstream.


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## Tesseract (Sep 27, 2008)

ruckus said:


> Many folks on this forum are financially linked to brushed motors continuing to sell despite their high failure rate.  I have no allegiance other than searching for a reliable and affordable solution.


You mean folks like me, right? So what's stopping the rest of the internet from coming down on my head if I write something about BLDC systems that isn't accurate?

And didn't you say in another post that you are trying to import a BLDC system from China for the purpose of reselling it? Seems to me you have a financial incentive that you ought to be disclosing yourself...


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## ruckus (Apr 15, 2009)

Tesseract said:


> You mean folks like me, right? So what's stopping the rest of the internet from coming down on my head if I write something about BLDC systems that isn't accurate?
> 
> And didn't you say in another post that you are trying to import a BLDC system from China for the purpose of reselling it? Seems to me you have a financial incentive that you ought to be disclosing yourself...


Hi,
Sure, you and a lot of other people. You might not realize that your posts carry a fair bit of weight on the forum as both a manufacturer of what many consider to be the best available components and as someone with 2000+ posts. These are both admirable and you have my full respect. So when you cast doubt on competing tech with zero data to back that up, people take your word for it. Further, when you represent continuous output as peak output to make the competing product look weak, it seems as if that is not by accident.

If you read the thread where I discuss importing the BLDC motor you will find that I am offering it at COST as a group buy. My clearly stated goal is to test the system, not to make profit. I do not think adding a few hundred bucks onto an imported motor is a viable business plan. How many would I sell a year? 3? 4? Hardly worth it. I am interested in finding a reliable and affordable drive system and sharing it with the EV community. That is my goal.

I also believe the brush problems we are seeing could be mostly solved by 1)upgrading to higher quality brushes -which is already happening at Netgain. and 2)by fitting MUCH wider brushes (along the length of the comm, not around it). This would help distribute the heat and electrical energy over a larger area. Heck, how about some real springs while we're at it.

But the first step in solving a problem is to admit there is one..

At this time the Brushed dc camp just keeps repeating the dogma that everything is fine and these motors are reliable. This is not found in the data. Unlike your comments about BLDC, I am not speaking from speculation, but from actual experiences of me and other people.

If you are to say that BLDC have lousy low-end torque and unpredictable high-speed surges, then you need to grapple with the reality of the Powertec motors which show this to be absolutely and completely false.


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## hostage (Aug 2, 2007)

ruckus said:


> Your claim that Brushed motors are reliable and are only failing under abuse is not supportable by the experiences of many people.


I have a bit of experience with brushed DC motors and their failures (as well as reasons for failure), and I would have to say that unless you can provide data this argument is pointless. We have experienced <.4% failure of motors (CUMULATIVE) over the the past 14 years combined! Please provide me with data on brush-less DC motor failure rates for comparison now that you have data disputing your claim. If you consider your 4 examples to be *MANY*, I would have to dispute that as I know how *many *motors we've sold in the past 14 years. I'd also like you to know that all of the examples mentioned using NetGain motors were replaced under warranty. Will that be done by brush-less motor suppliers? You must also consider the EV environment and the fact that *many *people using these motors are not familiar with the do's and dont's of EV's, so there is quite a bit of "user error" in the .4% (this # counts Tim's motors twice, and the racing motors that have failed)

Brush selection is critical to the proper operation of a brushed motor. Incorrect brushes can cause numerous performance issues and failures.

BTW: I *am *a fan of brush-less DC motors, and I also like AC motors. The bottom line is that people should choose the motor that best suits their needs and budget. For EV drag racing it is hard to beat series DC. For cost effectiveness (in the proper application) and support, it is hard to beat series DC. From my experience most people are fans of one technology or another, be it computer OS's, gas engines or electric motors. This debate is like Apple vs Microsoft, Ford vs Chevy. Technologies have a niche or they don't survive. And, evolution will help weed out the weak and unfit. Someday, that may mean series DC motors, so we must keep our eyes and options open and not become blinded by what has supported us in the past, or what may support us in the future. Just my opinion, I could be wrong...


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## ruckus (Apr 15, 2009)

hostage said:


> unless you can provide data this argument is pointless. ..If you consider your 4 examples to be *MANY*, I would have to dispute that...people using these motors are not familiar with the do's and dont's of EV's, so there is quite a bit of "user error" in the .4% (this # counts Tim's motors twice, and the racing motors that have failed)


Didn't I just provide you with multiple examples? Does your google button not work? None of the examples were "racing". They were driving. Tim suffered a putty failure followed by a complete internal short. He is now on his 3rd motor. How do you pretend this was user error?



hostage said:


> Brush selection is critical to the proper operation of a brushed motor. Incorrect brushes can cause numerous performance issues and failures.


So you are saying Netgain spec'd incorrect brushes? This we can agree on. I am glad you are willing to admit this. 

Instead of yelling at me to provide you with more data for you to ignore, how about asking my opinion on what would solve these problems? Despite your aggressive attitude, I will give you these anyway. I am sure you already know them as they are obvious to even the casual observer.

1)stop using forklift brushes and get some good ones. Netgain is already doing this.
2) Use MUCH wider brushes length-wise along the comm. More surface area = less heat and stress per area. I mean HUGE (or a 3rd set).
3) Get some real springs.

If you bother to talk with the folks who know stuff (like at Helwig) you should already know the current brush holder begins to fail and bend when adequate spring pressure is used. The current holder also flexes and moves under temperature changes creating less-than perfect contact. You could fix all of these problems in one fell swoop with a new and stronger and longer brush holder instead of just attacking me for telling you what you already know in your heart.

Who are you anyway mr. junior poster? You talk as if you represent Netgain but fail to list your credentials or position. Are you in the mail room? Design? Testing? Obviously you are not impartial. I only want a reliable drive system I would trust to give my grandmother. I can help you develop that through collaboration and idea-sharing or you can make a fool of yourself by blatantly ignoring what is obvious. Your choice.

Cheers

P.S. You owe me $14,000 in design-consultation and engineering fees. Should I send you a Paypal invoice?


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## ruckus (Apr 15, 2009)

zsnemeth said:


> Would You start Your own thread with a topic like: Brush trash, a.k.a. all hail BLDC! and keep this crap there!!!!!!
> 
> What You are doing is highly OFFTOPIC!! The OP is in Europe, He needs a motor+controller WITH E or EC marking, the system You are promoting doesn't have.
> Case closed, move on!


This is the response to helpful suggestions for motor improvement? Don't I say Series motors have potential if the issues are openly dealt with? I am not "promoting" any system. I am "looking" for a reliable solution. When a new potential user is considering the motor options, they should be aware of any problems those motors are experiencing.

If you have the OP interest at heart, then why not talk about relevant issues like brush motors will most likely fail European certification due to brush dust creating low-level electrical conduction to the chassis if the motor has been broken in or used much before cert testing? How about supplying a list of E or EC motors?

It is the repeated denial of failures and aggressive attitudes like yours that is creating the problem. If users said, "yes there are some issues, but here is how we suggest dealing with them..." that would be honest and positive discussion. Instead, you just gang up on anyone who dares to bring up actual cases of motor failure. I am serious that I am getting PM's from folks who are saying, "this happened to me too, but I am afraid to speak up". Now I know why. The messenger gets shot.. Are you not familiar with the recent thread where motor failure is met with aggression and accusations?
http://www.diyelectriccar.com/forums/showthread.php/amd-fb1-4001-motor-failure-73628.html
Another honest and helpful user shunned away to another forum where people listen and solve problems together instead of attacking each other.

I think it is best for the industry to deal with these issues openly and honestly. Your post does nothing to contribute to the discussion about motors and is the one off-topic. You make no positive suggestions to the OP like saying that regardless of which motor he chooses he should upgrade the brushes to Helwig split redtop. That one change might be all that is needed for brush motors to live on in infamy. Instead you come from nowhere using profanity to scare away honest discussion. Where is your positive contribution to the forum? It must be in your other 32 posts.. 

Loud-mouth "junior" posters are often hidden-identity trolls or users that were previously banned. I suggest getting a few more posts under your belt before breaking out the cuss words.


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## somanywelps (Jan 25, 2012)

ruckus said:


> It is fun trying to keep up with you on the forum. You are a fast.
> 
> You can nit-pick the list if you want, but that is the tip of the iceberg. Don't assume heat-related failures are operator fault. If the motor is having brush issues it will cause extreme heat even at low power output. I have personally seen this. I gave you enough links and instances. If you bother to google you will find many more. You can also look in Evabum at higher mile EV's. The number of brush failures that take out the motor are fairly common.
> 
> ...


You didn't answer the question, but yes, this is offtopic.

Make a new thread if you want, but you're going to need linkable sources.


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## ruckus (Apr 15, 2009)

somanywelps said:


> You didn't answer the question, but yes, this is offtopic.
> 
> Make a new thread if you want, but you're going to need linkable sources.


I suggest you go back and read the original post. 

My subject matter is definitely NOT off topic. The original post is inquiring about motor suggestions. He was then told to use 11" series dc. He replied that he was not real crazy about them. Then the Scott Drive came up and the series dc folks (who make money off them) came unglued at the mere suggestion that brushes may suffer from reliability problems. First the fan-club denies any failures. Then when I point to just a few well-known examples they say that isn't good enough and I need better links and more data.. yada yada. AGAIN. Is your Google broken? mine works fine.

You and a few others here are ignoring the data and helpful suggestions presented and pretending that I am the one off-topic.

Did you not read the OP's 2nd post? What about him not liking brushed motors didn't you understand? Did you just find that unthinkable? Where are your positive suggestions? Your responses are only detractions aimed at the data that I have presented in response to your previous attacks.

Again, the motives of those who only attack must be questioned. Why is it so unthinkable there might be some issues with the motors that needs resolution? Throughout the history of the forum many generations of equipment and different designs have been tried, failed, modified, and then used successfully. How have forklift motors suddenly gone from "experimental" to "old-reliable"?

The man said he didn't want one. Why can't you accept that?


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## DavidDymaxion (Dec 1, 2008)

Uh, Ruckus, you'll have to take my Kostov failure off the "just driving" list and add it to the "abuse" and "racing" list! Note my avatar pic below! Here it is right in the text for ease of viewing! 









I built my car with the intent to run it on the Salt Flats, autocross it, run on the big track, and maybe even throw in a drag race for fun. I have done and do all these things with my gasser, and have done the Salt Flats with the electric.

Though I was advised to run my Kostov at less than 800 Amps by a NEDRA racer, I chose to run it at around 5x spec at 1000 Amps. My homemade controller had a subtle fault that overcurrented a comm bar so it lifted (it's a sepex motor, so that is much easier to do than in a series motor). The next time I raced it (on the Salt Flats) that comm bar flew out, taking out the brushes along the way. At least I coasted through the lights at 59 mph on just 96V







Before the fault, I had done many ~1000 Amp bursts, and ~500 Amp regen bursts (including towing it behind a truck for "tow regen", a far faster way to recharged than any wall plug! BTW I was warned this was hard on the motor, too, but it lapped it up.).

I don't have an EV company, and I don't have any financial interest in any EV company. I really do wish an AC propulsion setup, or something similar would give me 150+ kW for $5k -- but it's more like $20k to $30k. So I have ordered a new Kostov (~$2.5k) and will use my Kelly controller (~$2.5k) for for a total of $5k for 144 kW nominal. The new Kostov has a much larger commutator, better comm bar retention, and better cooling. For $2.5k I can afford to completely ruin 8 to 12 of these motors and still be cheaper than an AC solution. I don't expect it to be that bad, but I will lean hard on the motor, too.

So don't get me wrong, I hope a cost effective BLDC or AC solution comes out. I appreciate folks like yourself that will put their money where their mouth is, take a risk on a lesser known foreign product, test it and report about it. I was nervous about getting a Kelly, but so far it has worked for me.


ruckus said:


> ...
> DavidDymaxion "blew" the brushes in his Kostov.
> ...





ruckus said:


> Didn't I just provide you with multiple examples? Does your google button not work? None of the examples were "racing". They were driving. ...
> ...





ruckus from another thread said:


> ...
> Why are you pretending this is some type of rare event caused by abuse? ...


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## ruckus (Apr 15, 2009)

DavidDymaxion said:


> Uh, Ruckus, you'll have to take my Kostov failure off the "just driving" list and add it to the "abuse" and "racing" list!
> I really do wish an AC propulsion setup, or something similar would give me 150+ kW for $5k -- but it's more like $20k to $30k. I hope a cost effective BLDC or AC solution comes out. I appreciate folks like yourself that will put their money where their mouth is, take a risk on a lesser known foreign product, test it and report about it. I was nervous about getting a Kelly, but so far it has worked for me.


Wow, the magic of a positive post. Glad the Kelly is working out. Sounds like it is able to put out the juice without issues. What is your cooling setup?

Even if you chalk your Kostov failure up to "racing", Somanywelps and the other drones simply refuse to acknowledge the failures that are happening from regular users (if there is such a thing).

I can't get you 150kw for 5k, but maybe for 6 or 7. Let me know. If you want used parts we might be able to do 250kw for 5k.


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## Tesseract (Sep 27, 2008)

ruckus said:


> So when you cast doubt on competing tech with zero data to back that up, people take your word for it. Further, when you represent continuous output as peak output to make the competing product look weak, it seems as if that is not by accident.


I confess I only gave the datasheet for the "Scott Drive 100" a cursory glance, but I have many years of experience dealing with datasheet exaggerations and this one was no exception.

The first issue is the disagreement between the "rated" voltage of 320V, the maximum speed of 4000 RPM and the BEMF coefficient of 0.64V/radian/second. Converting 4000 RPM into rad/s gives 419 rad/s the result, and multiplying that by 0.64V/rad/s gives 268V. Thus maximum RPM is reached with just 268V, yet "rated" voltage is 320V; a voltage that would spin the motor up to 4776 RPM. Generally speaking, you don't want to overspeed a BLDC motor any more than you do a series DC motor, and for much the same reason: stuff gets flung off the rotor (magnets in the case of the BLDC; comm bars in the case of the series DC).

Then there is the "phase current average" rating of 171A vs. the "rated" current of 121A. Which one is it? Above a certain current - especially if the motor is stalled - the rotor magnets will be damaged through demagnetization. Partial demagnetization results in a loss of torque; catastrophic demagnetization results in a 100% loss of torque. 

Moving right along, the overload torque rating is 275Nm and the "rated" torque spec is 104Nm, and since torque is proportional to current in a BLDC motor, that implies that the phase current required to reach overload torque is 320A. This is a trapezoidal type BLDC where only 2 of 3 phases are energized at any given time so the power calculation is straightforward: RMS phase current * RMS phase voltage = Power. If you multiply 320A by 320V you get 104kW, which is pretty close to the claimed 10 second rating. But that requires violating the speed limitation of 4000 RPM. If you instead multiply 320A by 268V, you then get 86kW. So I was off by a little bit when I said 80Kw peak, but pretty close for an off-the-cuff estimate.

Note that 121A * 268V = 32kW, which is pretty close to the 35kW continuous rating. 




ruckus said:


> If you are to say that BLDC have lousy low-end torque and unpredictable high-speed surges, then you need to grapple with the reality of the Powertec motors which show this to be absolutely and completely false.


I said that *trapezoidal* BLDC motors have relatively poor low RPM torque and suffer from lots of torque ripple *compared to sinusoidal BLDC*. That's just a fact of engineering, and no different than saying that shunt DC motors have terrible starting torque but excellent speed regulation with load changes, or that series DC motors will fling themselves to pieces if run at high voltage with no load. 

On paper the Scott Drive 100 system seems poorly suited to traction applications. If the motor were a sinusoidal BLDC type and the inverter used FOC then it would be fantastic, but neither seems apply here.


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## subcooledheatpump (Mar 5, 2012)

It's those disadvantages that turn people off to AC, and specifically BLDC. A BLDC motor could be totally destroyed by demagnetization, you could never fix it yourself, and you'd spend alot for it in the first place. The low end torque is poor and there is always a field excited so you can't effectively turn it "off" unless you have a contactor to disconnect it from the inverter. If the phases ever shorted, that always excited field would get you into serious trouble if the wheels were turning, regardless of inverter protection. 

Brushed DC motors can atleast be repaired at less than a "fortune" (whatever your definition of a fortune is, but a BLDC will cost you that) The brushes can be fixed and their fields can be shut off (not permanent magnet) 

If you're going AC then why not induction? Might not be as efficient, but to me, makes more sense. People always say "forget industrial" but honestly, it makes more sense than a Chinese noname BLDC setup.(has it even been tested?) Just my thoughts. 

Has the OP got his answer yet or is this a giant AC DC war?


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## ruckus (Apr 15, 2009)

I guess there's "on paper" and then there's the real world. Here is a BLDC bus.



















Are you SURE it's gonna have poor starting torque? That just doesn't jive with bus physics (aka real heavy).


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## subcooledheatpump (Mar 5, 2012)

Physics says (and the real world says too) Induction motors have better starting torque. 
Here is a freight Train (bigger, and heavier.) (by the way, before they used induction, they used brushed DC)









This is the motor, no magnets


















This is the induction motor from a tesla roadster. If I'm not mistaken, it is the highest performing production electric vehicle.









This is the buckeye bullet, If I'm not mistaken, this is the fastest electric car in the world. 

Also, if i'm not mistaken, it uses a custom made 400 HP induction motor (made by a company that makes induction motors for mining carts)

And just for fun, and for refrence 









This is my van. Almost 8000 LBS. it uses an induction motor

Also, I've seen those silly Powertec BLDC motors. They are too big and too heavy and offer too little output for their size and weight


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## DavidDymaxion (Dec 1, 2008)

Not sure if you meant motor or controller cooling, so I'll hit both. My Kelly is a sepex. I was warned Kellys run hot, but I can't feel any warming whatsover on mine. Maybe the sepex leads an easier life as it in theory doesn't need to do current multiplication and in theory does less high current switching. Mine sits on a huge 11x17 inch heatsink with a 12 inch car radiator fan -- it runs so cool I don't run the fan anymore.

The old Kostov had the internal fan and a bilge blower blowing from the side through a brush hole. I believe that blowing through the end bell, like the new Kostovs do, will be better.

I have already purchased my replacement Kostov, but would consider a comparably priced AC or BLDC of similar or higher power for a future motor need. I also like some success stories for things I buy -- the fact that Wayland was able to so thoroughly stress test his Kostov gave me confidence to buy one.

FWIW, I've never heard of a DC motor failure for my local EV club (around 15 EVs), besides my own. They are the 144V 500A crowd. One of them also has a Kostov, there's one Warp, an etek, and I think all the rest are Advanced DC. On the flip side a local university has struggled to keep their AC vehicle running reliably.

The url in your sig www.northvalleyev.com shows what appears to be a series DC car, have you done a BLDC car yet?


ruckus said:


> Wow, the magic of a positive post. Glad the Kelly is working out. Sounds like it is able to put out the juice without issues. What is your cooling setup?
> 
> Even if you chalk your Kostov failure up to "racing", ... the other ... simply refuse to acknowledge the failures that are happening from regular users (if there is such a thing).
> 
> I can't get you 150kw for 5k, but maybe for 6 or 7. Let me know. If you want used parts we might be able to do 250kw for 5k.


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## ruckus (Apr 15, 2009)

subcooledheatpump said:


> I've seen those silly Powertec BLDC motors. They are too big and too heavy and offer too little output for their size and weight


Are you nuts? Did you bother to read the specs? One more time:
Powertec E215e2
211 lbs WITH BLOWER
86 hp @ 3600 rpm CONTINUOUS
95 hp @ 5000 rpm CONTINUOUS
500 ft lbs Torque 0-2000 rpm. Yes, full torque down low. 
640vdc

Where is the "silly" part? Please tell me cause I can't see it.

Powertec has different magnet types, voltages, and enclosures. Since they are used in mines some must be totally enclosed with ZERO ventilation and thus have lower rated hp for their size. You have to actually read the specs on the blower ventilated motors with the high-speed winding connections.


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## ruckus (Apr 15, 2009)

DavidDymaxion said:


> The url in your sig www.northvalleyev.com shows what appears to be a series DC car...


Yes, that is how I know they have brush issues.  I determined that BLDC was the next technology I wanted to use. I searched to find the motor with the best specs. It was out of China in 3 frame sizes (the larger is used in buses). Then, lo and behold, I see this same motor (or at least a de-tuned version of the mid-sized one) coupled with a fancy New Zealand made controller called the Scott Drive. I called them up and requested the "Full Monty". It looks promising that I can get a "hot rod" version of the goodies for testing by this summer. Here are the totally unconfirmed preliminary "maybe" stats which are subject to change and might just be numbers on paper:

187 lbs
540vdc
500NM torque (369 ft lbs)
60kw (80 hp) continuous
120kw (160 hp) pulse

If I can get it up to 640+vdc  the stats should be even better, but we'll see. Now, about those batteries...

Cheers


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## drgrieve (Apr 14, 2011)

With the Jack Rickard and Tim motor failures what was that to do with brushes? IIRC their balancing putty fell off.

So I'd agree there is possible an issue with this part of Netgains design - but I'm sure they are all over it.

Perhaps a better way to approach this topic would be to approach it positively. For example a topic based on -> How to improve the design of brushed DC series motors.

I would be interested in reading peoples thoughts on that topic. I would be interested in hearing on how to get brake support for example - though I guess that would be off topic as that could be considered a controller thing - lol!


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## subcooledheatpump (Mar 5, 2012)

I'm interested in that Powertec motor you mention, if it really has those performance specifications. I looked up the number, couldn't find anything. 


All I can find are Powertec motors that are about 40 HP and weight 400 LBS. 

Not that those numbers aren't impressive (if they are for real) but there are induction motors that are still lighter for the same power. (half the torque but twice the power)


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## somanywelps (Jan 25, 2012)

ruckus said:


> Are you nuts? Did you bother to read the specs? One more time:
> Powertec E215e2
> 211 lbs WITH BLOWER
> 86 hp @ 3600 rpm CONTINUOUS
> ...


What controller?


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## ruckus (Apr 15, 2009)

somanywelps said:


> What controller?


First you claim there are no brushed motor failures unless overloaded, then you deny the ones put in front of you.

Then you claim BLDC have low torque. I show they don't.

You say I'm off topic but then switch to asking about controllers in a thread on motors in the motor section of the forum? 

Sorry, off topic.

If you want to learn about controllers post a question in the controller section.


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## ruckus (Apr 15, 2009)

subcooledheatpump said:


> I'm interested in that Powertec motor you mention, if it really has those performance specifications.


Ok, go here:
http://www.powertecmotors.com/pactorq.html
Scroll down, down , down. DON"T LOOK AT THE CHARTS ON THAT PAGE since they are the 1750rpm ratings. Keep going down down down -and at the bottom click on the 210.pdf link..
Some of the other sections (tech and Intro) have interesting info as well.

Make sure to look at the high-rpm connection (E2). Other connections are low rpm and thus have low hp numbers.

edit- forgot to mention that the DPBV (drip-proof blower ventilated) figures are what you want, not the TENV (totally-enclosed non-ventilated).
2nd edit - please don't think I am endorsing the Powertec products. I'm not. I do not think air cooling is the way to go. (noisy and innefficient) Air is about 30 times less efficient than liquid cooling. Also, if you call them and request a price sheet they probably will just hang up the phone and figure you are crazy and never send it. Bummer. Also, they are only affordable on Ebay or surplus.
Cheers.


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## ruckus (Apr 15, 2009)

drgrieve said:


> With the Jack Rickard and Tim motor failures what was that to do with brushes?


1 failure was putty. 1 failure was unknown. 1 failure was BRUSH dust causing full motor short. What about the brush "burnout" in the recent thread in this forum I linked? (9") Those are just the tip of the iceberg and well documented. 

They were all brushed DC motors. That is the relevance.

I believe many failures that are blamed on overheating are actually caused by the brushes CAUSING that high heat. (See the last 2 EVTV if you want documentation) I have seen (forklift quality) brushes causing high amounts of heat while performing well under the rated hp load. That is why I personally am pursuing 2 avenues.
1) Upgrage ALL brushes in brushed motors to Helwig split Red top. and
2) Testing other drive system options.

I am certainly not saying they are junk and not bashing them. I am merely bringing their well-documented problems "out of the closet" when folks continue to recommend them to the original poster even after he said he wasn't interested.

Not interested means not interested. The BDC fanclub is starting to use mob tactics, group-trashing anyone who dares even mention another drive system.

This is sad. It is a repeat of the Lead-acid lovers who spewed much hate at those who dared to mention those newfangled "untested" "Chinese Junk" batteries. (LiFePo4)


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## subcooledheatpump (Mar 5, 2012)

I have to admit, those are some pretty impressive figures. 

But, right in the datasheet it warns about the demagnetization limit and says the "user should apply appropriate saftey margins".... I don't know, a motor that could be demagnetized isn't for me, especially one of that size/cost. The kicker is too, it would be demagnetized right when it counts, during peak torque. (on a hill maybe?)

Consider this, a Siemens induction motor "Aluminum series 1LE1001 with increased output"

Product ID:1LE1001-1DA6.-.... 

This motor weights a little less (200), and could possibly output the same continuous power(100 kW) provided with an external blower, like the powertec has, and it more than likely will cost less, and will never be demagnetized. Torque won't be the same(200 FTLBS) and peak power won't be the same(150 kW), but still. To me a motor I can't accidentally break is worth it


Sorry OP for my part in wrecking your thread


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## ruckus (Apr 15, 2009)

subcooledheatpump said:


> I have to admit, those are some pretty impressive figures. but.... I don't know, a motor that could be demagnetized isn't for me, especially one of that size/cost.


Reports of demagnetization are greatly exaggerated. Any motor type can be damaged from excessive heat and current. Those are both easy to limit and monitor. (much like a series DC is EXTREMELY vulnerable to overspeeding and thus need rpm limiting)

Controllers easily damage themselves with heat. That is why the new round of controllers (and some of the older ones) monitor their heat and cut back the output accordingly. No big deal.

Motors are no different. Limit the current (but not the voltage  ), Limit the output (if necessary), under high heat conditions. This is already done for you by the controller.

No Problem.

If BLDC were sketchy and prone to failure (as the BDC mob would have you believe), they would not be chosen by industries where performance and reliability are critical to human lives.

The mob knows that just a bit of a doubt is enough to control most folks.. Aren't you worried about comm damage from brush arcing?
Doubt can be manufactured.


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## subcooledheatpump (Mar 5, 2012)

Well I'm not saying Brushed DC is better, I know it's not actually better, it's just cheaper and eaiser. 

Which may possibly make it better for the DIY crowd, especially when you couple that with the available controllers. 

There is no question about it, a brushless DC motor doesn't have brushes to go bad and won't suffer the overspeed problems. Everything has its own advantages and disadvantages though. 

The high cost of a BLDC, plus the controller, plus the fact that it can technically be damaged, just like a brushed motor could be, leads most people to say yes, it technically is better but is it practically better?

Thats really what the people here are trying to say, a regular Brushed DC motor from a practical point of view, for DIY converters is probably better. 

Personally though, I would never put a brushed motor in a vehicle. I always have (and probably always will) use(d) induction. ( I had to basically make the controller though, another turn off for anything AC/Brushless, availability of EV voltage friendly controllers)
Maybe BLDC in the future, since the powertec looks pretty good.


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## DavidDymaxion (Dec 1, 2008)

I would like to hear how your motor failed.

Please report how your BLDC system works, I'll be reading with interest.

Do be careful with Voltages that high.

You could run with a single string of Headways to test -- not great range but much cheaper than 100 Ahr cells!


ruckus said:


> Yes, that is how I know they have brush issues.  I determined that BLDC was the next technology I wanted to use. I searched to find the motor with the best specs. It was out of China in 3 frame sizes (the larger is used in buses). Then, lo and behold, I see this same motor (or at least a de-tuned version of the mid-sized one) coupled with a fancy New Zealand made controller called the Scott Drive. I called them up and requested the "Full Monty". It looks promising that I can get a "hot rod" version of the goodies for testing by this summer. Here are the totally unconfirmed preliminary "maybe" stats which are subject to change and might just be numbers on paper:
> 
> 187 lbs
> 540vdc
> ...


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## somanywelps (Jan 25, 2012)

ruckus said:


> First you claim there are no brushed motor failures unless overloaded, then you deny the ones put in front of you.
> 
> Then you claim BLDC have low torque. I show they don't.
> 
> ...


Nice try at evading the question, I asked this 3 times earlier, 4 with that comment, 5 with this one.

*What controller?*


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## ruckus (Apr 15, 2009)

So you have dropped the false arguments against BLDC and admit there are troublesome rates of BDC failures occurring which the EV community should work together to solve? 

Seems like that is the case. 

Now you command me to design a system for you since your Google button remains broken? Yes sir.

There are many controllers which could be used. What are your desires?
Power?
Small form factor?
Reliability?
extra functions?
low cost?
CAN bus interface?
punch-card interface?

You could be enterprising like Heatpump and build your own. But that would require fixing your google button and using it. Not to mention a little math and some chutzpah. If you want to go the Ebay/salvage route there are plenty of powertec and other industrial controllers out there. If you want a new out-of-the-box EV-ready solution, why not use the Scott?

Again, if you want to learn about controllers, post a question in the controller section. You seem to be implying there aren't controller options for BLDC available which just shows everybody you haven't bothered to research the topic. If you can fix your google button, "BLDC controller" returns 762,000 hits. Might be a good place to start.


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## somanywelps (Jan 25, 2012)

ruckus said:


> So you have dropped the false arguments against BLDC and admit there are troublesome rates of BDC failures occurring which the EV community should work together to solve?
> 
> Seems like that is the case.
> 
> ...


Your $10,000 motor is half the problem. There are tens of thousands of BLDC controllers, I want *you* to select a controller that would match your motor. The problem is there isn't an affordable *EV* controller that matches it. 

Again, *WHAT CONTROLLER*?


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## ruckus (Apr 15, 2009)

somanywelps said:


> Your $10,000 motor is half the problem.


Of what, world hunger? Do you realize how you sound? 

Again, it's not "my" motor. I wouldn't use any air-cooled motor unless I got it real cheap on Ebay or something. I have repeatedly told you I only posted the stats because it shows that your argument of low torque is at worse a lie and at best uninformed drivel.

Go back and read my post. I already told you the answer to your question. What is the point of giving you information if you won't even bother to read it?

Jabbing at the reply button is not a great way to learn stuff. 

Most people here are happy to share, but not when you act like a mindless bully.

Cheers


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## Elegancec (May 23, 2012)

Hello Ruckus and somanywelps.
Can you please go ahaed with your discussion with private message.
Thank you for your comments.

Thanks a lot!


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## somanywelps (Jan 25, 2012)

Elegancec said:


> Hello Ruckus and somanywelps.
> Can you please go ahaed with your discussion with private message.
> Thank you for your comments.
> 
> Thanks a lot!


I was trying to figure out if he had a valid option for you. As it turns out, he doesn't. The cheapest controllers are currently $6000-7000 and I'm not sure they can hit the required voltage.

So BLDC/AC is off the table for anything above 50kw. (There are issues with the scott drive, not to mention it's untested).

You have the brushed DC recommendations.


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## Elegancec (May 23, 2012)

http://www.moveandmeet.de/uploads/pics/move-meet-4883.jpg

Hi this is a picture from the latest fair on which I have been with my Z3, equipped with Warp 9 engine in North of Germany.

http://www.moveandmeet.de/uploads/pics/move-meet-4878.jpg


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