# NetGain Motors upped their voltage to 192VDC?



## AmpEater (Mar 10, 2008)

COS said:


> I didn't want to hijack the other thread below but there was mention that they increased their rated voltage to 192VDC.
> 
> http://www.diyelectriccar.com/forums/showthread.php/ideal-motor-zilla-31655p2.html
> 
> ...


Electrocraft is the only controller available besides the Zilla HV that does over 156V I am aware of, making it the only actually available.


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## rillip3 (Jun 19, 2009)

My understanding is that Netgain has not actually upped the actual voltage recommendation, but has acknowledged that there's still a little room at the top for more, as long as the amperage isn't too high.. I don't think you'll find any official updates with higher specs anytime soon, and nobody I know of has the ~$2000 to blow to test and see how long it can handle the higher voltage.


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## AmpEater (Mar 10, 2008)

rillip3 said:


> My understanding is that Netgain has not actually upped the actual voltage recommendation, but has acknowledged that there's still a little room at the top for more, as long as the amperage isn't too high.. I don't think you'll find any official updates with higher specs anytime soon, and nobody I know of has the ~$2000 to blow to test and see how long it can handle the higher voltage.


Just need to find 20 people to whom that info is worth $100 each.....or 200 who value it at $10 (probably much closer to how much I'd pay for that tidbit)......but to someone who is risking $2000 pushing the limits $100 would be a steal to know where they are.


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## Qer (May 7, 2008)

While I don't have any reason to doubt NetGains claim that their motors can handle 192 Volt I, however, doubt that the motor will survive high voltages AND high current at the same time, especially if it's for any longer periods of time. Here's some stills from a video I got today from the latest set of test runs:

First flash. This is about a second after the motor has accelerated up to speed (which means the motor runs at approximately 100 Volt and 1000 Ampere), 7 seconds into the video (the recording started about the same time as the motor got power).










Second flash about a second later. So far the flashes are rather far apart and probably no problem. As you can see the motor is pitch dark inside except for the flash, that will soon change...










Third flash at 12.5 seconds into the video, still no problem.










At 13 seconds the flashes are starting to last longer. Not good.










15.5 seconds (9.5 seconds from when the motor reached the desired current and voltage) and now the light show is more or less permanently on.










Almost 17 seconds, the flashes are getting bad.










17 seconds...










Almost 18 seconds. The light show is quite spectacular and a bit unnerving...










20.5 seconds (about 14 seconds at 1000 Amps). All brushes seem to be on fire, this is when Tesseract decided it was time to cut the power!










So even if it's quite impressive that the WarP's can handle 192 Volt, I doubt that they can handle it if you really start to torment them. After a run like this we have to run the motor for a while on a more sane current (200-300 Amps) to recondition the brushes again. If you keep pushing the motor you will most likely get a flash over and then the motor is toast. With higher voltage it's more likely to happen faster, so it's probably a VERY bad idea to really be going for those 192 Volts unless you're prepared to pay for it when things start to break.

Oh, and I want to point out that I don't think NetGain are doing bad motors! I bet that an ADC or Kostov would also create lots of sparks if they were treated like this. It's a limitation in the construction, the brushes etc aren't rated for this amount of power so they heat up faster than the air flow can cool them down which will, ultimately, destroy them and turn the motor commutator into a plasma ball.

Wanna see the whole video? It's here:


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## COS (Dec 23, 2008)

Nice vid bro!!

I will probably stay at the 165VDC range. My planned conv is more a commuter pickup but want the ability to hit the freeway for a few miles. 

Was that a Warp 9 or 11?

Just a note, isn't it always highly recomended to not ever ever ever run the Warp motors without a load?

Edit:
I highly doubt I will ever go beyond 400Amps anyway.
________
Vapormatic vaporizer


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## Qer (May 7, 2008)

COS said:


> Nice vid bro!!


Thank Tesseract, he's the guy that risked his behind. 



COS said:


> Was that a Warp 9 or 11?


WarP 9", but I don't think it matters much since 1000 Amps is serious abuse no matter motor. Kostov rates their 11" to 260 Ampere continuously (ok, one hour, but that's rather continuously for an EV). I doubt a Kostov 11" would fare much better at 4 times over current and if you start to reach top voltage at the same time the risk for flash over increases tremendously.


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## AmpEater (Mar 10, 2008)

Qer said:


> While I don't have any reason to doubt NetGains claim that their motors can handle 192 Volt I, however, doubt that the motor will survive high voltages AND high current at the same time, especially if it's for any longer periods of time. Here's some stills from a video I got today from the latest set of test runs:


What is providing the load for that test?

And I have an issue with the whole concept, I don't believe its ever really possible to draw 192v AND 1000A with a 192v/1000a controller. Where the current is very high (launch) the controller will undoubtedly be limiting the PWM cycle to limit the current, so the effective voltage will be low even with the pedal floored. Once you get up to speed (lets say you're on the highway with the pedal 2/3 depressed) the motor is "seeing" 120 volts or so and you floor it again, you only have another 60 volts (less with sag) to demand more current, which is not nearly enough to produce a 1000A draw. 

Back EMF prevents high voltage and high current from occuring simultaneously. 

You can even feel this driving, I certainly could in my EV, the faster the motor is spinning the less acceleration (amps) you get.

Just a techical point, a test bench says more than a theoretical understanding of what should be happening.


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## Tesseract (Sep 27, 2008)

AmpEater said:


> What is providing the load for that test?


A hydraulic-pump based engine dyno rated at 250hp. The test bench battery pack is 16 105Ah Deka AGM batteries. The duty cycle during these 1000A test runs has consistently ranged between 60 and 70% and the pack voltage sags to around 155-165V depending on the SOC. I am pulling a solid 600-700A from the battery pack, in other words, and the motor is seeing approximately 100V at 1000A (100kW). I can dial the load down on the motor so that the duty cycle goes to 100% but I suspect motor amperage will have to stay below 600A to prevent its destruction. 




AmpEater said:


> And I have an issue with the whole concept, I don't believe its ever really possible to draw 192v AND 1000A with a 192v/1000a controller.


a. You have an issue with the testing method, huh? Fine - post a bond to me in the amount of $1800 - the cost of the motor - and I will increase the size of the battery pack until there is a full 192V across the motor at 1000A. If the motor is destroyed I'll keep the $1800 and you can keep the video of the event. Sound fair?

b. NetGain raised the voltage limit on the motor to 192V, but did not provide a corresponding amp limit at that voltage - at least George didn't to me the last time I talked to him. I can let the motor run faster, while runing a much higher pack voltage, but at a greatly reduced load (maybe 500A through the motor) and maybe it will survive. The point is that it's the total amount of _power_ going into the motor that will destroy it, not just the voltage or just the amperage (within reasonable limits, of course).

Just in case it isn't clear, we are in business to develop a controller on par or exceeding the Zilla Z1KHV in every aspect, not testing NetGain's motors for them - that is only incidental to testing the controller itself.


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## AmpEater (Mar 10, 2008)

Tesseract said:


> A hydraulic-pump based engine dyno rated at 150hp. The test bench battery pack is 16 105Ah Deka AGM batteries. The duty cycle during these 1000A test runs has consistently ranged between 60 and 70% and the pack voltage sags to around 155-165V depending on the SOC. I am pulling a solid 600-700A from the battery pack, in other words, and the motor is seeing approximately 100V at 1000A (100kW). I can dial the load down on the motor so that the duty cycle goes to 100% but I suspect motor amperage will have to stay below 600A to prevent its destruction.
> 
> 
> 
> ...


No no, my issue is that my theoretical understanding of a series motors tells me max amps can only happen at lower voltage, as voltage increases your ability to pull lots of amps goes down.

But it looks like the motor resistance is just so low that 1000A is still achievable even with 100v of back EMF? Surprising

Anyways, very cool info. Like I said, I care alot more about the real thing on a real bench versus a conceptual model of a motor. 

And I thought we were talking about a 192v / 1000a controller, if you can increase the voltage until the motor is seeing a true 192v then the controller voltage would have to be much higher to account for sag. What upper limit are you designing for? If you have 300v to work with nothing I said applies to that situation


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## Qer (May 7, 2008)

AmpEater said:


> But it looks like the motor resistance is just so low that 1000A is still achievable even with 100v of back EMF? Surprising


Not really if you think about it. This kind of motors have an efficiency of close to 90% peak which means that the pure resistance (which translates to losses) has to be pretty low. We push roughly 100 kW through the motor, with a little less than 90% efficiency a little more than 10 kW turns to heat. That means a resistance of 0.1-0.2 Ohm which is pretty darn close to a short circuit even at 1000 Amps. It sure won't stop the motor from burning up if you give it the chance!



AmpEater said:


> And I thought we were talking about a 192v / 1000a controller, if you can increase the voltage until the motor is seeing a true 192v then the controller voltage would have to be much higher to account for sag.


Right now the pack used is a 192 Volt nominal lead-acid that, at 600-700 Amps battery current, drops down to 150 Volt. That means that even with this pack the motor could get a bit more than 100 Volt, 1000 Ampere (we've seen peak 110-120 kW somewhere), but not much more. With a Lithium pack with enough Ah the sag would be less and the motor would have an even harder life, even though it wouldn't get the full 192 Volt. But let's say it gets 150 Volt, that means 150 kW over the motor that sparks quite bad already at 100 kW.



AmpEater said:


> What upper limit are you designing for?


More. 

We need more batteries to verify it before we promise anything though...


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## Tesseract (Sep 27, 2008)

COS said:


> ...Was that a Warp 9 or 11?


WarP 9 - the amps vs. time ratings are the same for all of the WarP motors according to NetGain:

~225A for 1 hour
~450A for 5 minutes
~1000A for 20 seconds
~2000A for 10 seconds

This is strictly a winding/brush temperature related rating, though - nothing is said about the volts that can be tolerated by each motor at each amperage level (and I suspect those voltage tolerances _are_ different for each motor).




COS said:


> Just a note, isn't it always highly recomended to not ever ever ever run the Warp motors without a load?


Yep, but this motor _was_ heavily loaded... overloaded, actually, as it was delivering approximately 118hp net into the dyno.




COS said:


> Edit:
> I highly doubt I will ever go beyond 400Amps anyway.


I don't, especially in a pickup truck or other vehicle weighing over 3000# post-conversion an/or if you live in a place with hills that are steeper than "gently rolling". An _honest_ 600A will probably give you near-stock acceleration performance in such a vehicle (by "honest" I mean you need to have the 600A available for more than a couple of seconds...)


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## Bowser330 (Jun 15, 2008)

AmpEater said:


> What is providing the load for that test?
> 
> And I have an issue with the whole concept, I don't believe its ever really possible to draw 192v AND 1000A with a 192v/1000a controller. Where the current is very high (launch) the controller will undoubtedly be limiting the PWM cycle to limit the current, so the effective voltage will be low even with the pedal floored. Once you get up to speed (lets say you're on the highway with the pedal 2/3 depressed) the motor is "seeing" 120 volts or so and you floor it again, you only have another 60 volts (less with sag) to demand more current, which is not nearly enough to produce a 1000A draw.
> 
> ...


Well thats why you change gears right? To something more aggressive...to bring the motor speed low enough to be able to extract 1000A...I think its been mentioned that 1000A was drawn at 3000rpm with the evnetics prototype...

So if the warp-9 makes 200ftlbs at 1000A, Then Hp @ 3000rpm = 114 ...(HP = (Rpm x TQ)/5252)


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## Tesseract (Sep 27, 2008)

Sorry, Bowser330, but the last 1000A run was at 2000rpm, not 3000rpm. Input power to the motor was 105.4kW and net output power registered by the dyno was 88kW (118hp), which includes both dyno and motor losses.

This implies that the developed motor torque was somewhere between 309 and 370 ft-lbs at 1000A (with the latter being true if the motor and dyno were 100% efficient, which we know isn't the case).


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> Sorry, Bowser330, but the last 1000A run was at 2000rpm, not 3000rpm. Input power to the motor was 105.4kW and net output power registered by the dyno was 88kW (118hp), which includes both dyno and motor losses.
> 
> This implies that the developed motor torque was somewhere between 309 and 370 ft-lbs at 1000A (with the latter being true if the motor and dyno were 100% efficient, which we know isn't the case).


Ok, so 2000rpm, How many rpm will it increase at 300V?


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> Ok, so 2000rpm, How many rpm will it increase at 300V?


Theoretically? Assuming the motor can withstand this (and I seriously doubt it could)? Is that 300V across the motor (which it most certainly can not withstand except maybe briefly at 100A or less, I'd guess)?

Well, this is easy enough to figure out, regardless:

300V x 1000A = 300kW = 400hp

400hp x 0.85 = ~340hp net at dyno

(340hp x 5252) / 310 ft-lbs = *5760 rpm*

The maximum I expect we can achieve right now (at 100% duty cycle and with an estimated sagging of the pack down to 140V) would be:

140kW / 0.75 * 0.85 = ~160hp

(160hp x 5252) / 310 ft-lbs = 2710 rpm

[note: 0.85 is the motor efficiency multiplier]


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> Theoretically? Assuming the motor can withstand this (and I seriously doubt it could)? Is that 300V across the motor (which it most certainly can not withstand except maybe briefly at 100A or less, I'd guess)?
> 
> Well, this is easy enough to figure out, regardless:
> 
> ...


I understand the warp-9 would not be able to handle it, seeing as even netgain only recently upped the max voltage to 192V (which does fit perfectly with your 200V controller)..

I guess i incorrectly asked the question because I was asking while trying to compare an interpoled-kostov-11inch motor...and how it would react at 300V. My mistake for attempting to cross contaminate the motor and performance at x-rpm discussion...

So with Lithiums sagging less, say a 190V pack sagged to 170V (10%) 
170V/.75 *.85 = 193HP

(193hp x 5252) / 310 ft-lbs = 3270rpm

Is it accurate to say that with a Warp-9 + 200V eVnetics +lithiums, you could have about 200HP and 300TQ available from 0rpm to 3270 (motor) rpm?


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