# dc motor maintenance



## crashedup (Oct 28, 2008)

hello I was wondering what kind of maintenance is involved in dc motors and under normal driving conditions in 4 season weather, after how many km should this be done? 
Also to do any type of maintenance do you have to completly remove the motor to service it?


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## major (Apr 4, 2008)

crashedup said:


> hello I was wondering what kind of maintenance is involved in dc motors and under normal driving conditions in 4 season weather, after how many km should this be done?
> Also to do any type of maintenance do you have to completly remove the motor to service it?


Hi crash,

The typical DC traction motor which has been properly designed and manufactured and properly applied to the application and used as intended should last 10,000 to 20,000 hours without service. Say you average 30 mph; that would be 300,000 to 600,000 miles. However, on road EVs are not the intended application for these motor designs. Service voltage and RPM are generally higher; however the motors are not subject to plug reversals and run continually for 8 hour shifts twice per day. So my guess is you could expect 100,000 miles between service intervals, if the motor is in a quality installation.

These are DIY; so no guarantees. An improperly applied or improperly installed or improperly used motor could fail within hours or weeks or months. 

The typical DC motor used in these conversions will have sealed bearings lubricated for life (20,000 hours). However if those bearings are overheated, or misaligned, or improperly preloaded or side loaded, all bets are off. You'd have to remove the motor to replace a bearing.

Motor insulation has a half life of 20,000 hours if operated at rated temperature or below. Poor ventilation can cause overheat. Other factors can cause insulation failure (vibration, mechanical damage, etc.). Insulation repair requires motor removal.

Brushes are really a black art, but if they are right, they should go 10,000 hours before replacement. This requires the proper grade, properly sized for the load profile, proper commutator surface finish and runout, proper timing, contamination free operation, proper temperature and very importantly, proper break-in. Brush replacement might be done without motor removal, but in most cases, commutator should be serviced at that time and would need removal of the motor.

So who's to say if all these things are *proper* for the DIY EVcar converter? Chances are most will not get it all right. So, do the best you can. Get some experienced help if possible. Break in the motor. Check it out thoroughly before driving. Check it out after the first 10 miles. then 100 miles. Then 1000 miles. If you're good at that point and brushes are wearing normally, good comm film, no vibration, no strange noise, no strange smell, no evidence of overheating, check it again after 10,000 miles from then on.

Regards,

major


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## crashedup (Oct 28, 2008)

thanks for all that info! 
But my question is for all those diy'ers out there with netgains or kostov's , in real worl situations what has been youre experiances? how far apart have youre maintenance jobs on youre motors been, and what did it include?


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## dtbaker (Jan 5, 2008)

crashedup said:


> thanks for all that info!
> But my question is for all those diy'ers out there with netgains or kostov's , in real worl situations what has been youre experiances? how far apart have youre maintenance jobs on youre motors been, and what did it include?



few have been running long enough to require maintenance under 'normal' use. normal being not too far over voltage and not too over-amped for too long too often  

I do know that the guys at netgain are preparing a document to cover the most common topics on checking and replacing brushes...... but thats about it.

I'd suggest belly-pan to keep debris out, and wiring up the overheat sensor wires if your motor has them (probably). Probably good policy is to check brushes, battery balance at end of charge, and terminal torque every 6 mos... spring and fall inspection while changing tires.


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## dladd (Jun 1, 2011)

well... my motor had somewhere north of 10k miles on it when I bought the car. I've put another 10k on it in the last year. It's still going fine, other than the fact that I have a decent voltage leak to ground going through the motor (from brush dust I'm told).


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## crashedup (Oct 28, 2008)

Ok! thats the kind of stuff im interested in knowing, ive heard you have to clean the commutator once a year, and to do so i suppose you have to remove the motor?


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## dtbaker (Jan 5, 2008)

dladd said:


> well... my motor had somewhere north of 10k miles on it when I bought the car. I've put another 10k on it in the last year. It's still going fine, other than the fact that I have a decent voltage leak to ground going through the motor (from brush dust I'm told).



and what pray tell, were the symptoms of a voltage leak to ground? and the fix?


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## dladd (Jun 1, 2011)

dtbaker said:


> and what pray tell, were the symptoms of a voltage leak to ground? and the fix?


The symptom was I got shocked when I shouldn't have! I was leaning into the engine compartment with one hand on the old radiator support (vehicle ground) and I touched a pack voltage connection with the other hand. There was a small unmistakable tingle and I thought what the fuck was that!?! 

A little asking around and some probing with a multimeter lead me to realize there is a very small connection to vehicle ground through the armature of the Warp9 motor. I measured a current of 0.2mA from pack (+) to vehicle ground. I also discovered this is very common. And as of now, I have not yet done anything about it. 

I believe the fix is cleaning the carbon dust out of the motor, I plan to do that the next time I have the motor out of the car.


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## crashedup (Oct 28, 2008)

Couldnt you just blast away the dust with compressed air?


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## Roy Von Rogers (Mar 21, 2009)

dladd said:


> The symptom was I got shocked when I shouldn't have! I was leaning into the engine compartment with one hand on the old radiator support (vehicle ground) and I touched a pack voltage connection with the other hand. There was a small unmistakable tingle and I thought what the fuck was that!?!
> 
> A little asking around and some probing with a multimeter lead me to realize there is a very small connection to vehicle ground through the armature of the Warp9 motor. I measured a current of 0.2mA from pack (+) to vehicle ground. I also discovered this is very common. And as of now, I have not yet done anything about it.
> 
> I believe the fix is cleaning the carbon dust out of the motor, I plan to do that the next time I have the motor out of the car.


I'm lost here, how can you get voltage from motor to ground if it isnt running (not energized)??

The most common problems come from non isolated instrumentation or dc to dc converters.

Roy



Roy


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## JRP3 (Mar 7, 2008)

crashedup said:


> Ok! thats the kind of stuff im interested in knowing, ive heard you have to clean the commutator once a year, and to do so i suppose you have to remove the motor?


I don't think you want to clean the commutator unless you have uneven wear or gouging. The patina on the comm is part of the proper brush/comm interface and you don't want to remove it.


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## kennybobby (Aug 10, 2012)

Is your battery pack negative terminal grounded to the vehicle?


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## Yabert (Feb 7, 2010)

10000 miles done with my DC motor (Impulse 9). That include 6 month of running in dirty condition (winter, snow, slush, gravel road, dirty road, etc.) and despite than the outside of the motor is really dirty and seem really old (rusty), the inside is clean. Clean the air you put inside the motor and all will be fine.

I had a problem of brush dust and fast wear with the first grade brush (H49 (bad brush for daily use)) I used for the first few month, but there don't have now any sign of wear with the new brush (H60) and the brush dust seem low. 
I cleaned the motor between change of brush.


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## nat_ster (Oct 19, 2012)

So can you simply blast the carbon dust out with compressed air like previously asked?

Even if you only get 90% of the dust out this should help.

Or is the carbon dust magnetic and sticks to everything inside the motor?

Thx Nat


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## major (Apr 4, 2008)

nat_ster said:


> So can you simply blast the carbon dust out with compressed air like previously asked?
> 
> Even if you only get 90% of the dust out this should help.
> 
> Or is the carbon dust magnetic and sticks to everything inside the motor?


Sure, but use oil free compressed air. And brush dust is composed mostly of graphite. Carbon and graphite are not magnetic but will stick to everything.

Excessive brush dust is not the normal condition. If it is causing a problem in 10 or 20,000 miles, you have something else wrong, like Yabert with the incorrect grade. It is a good idea to clear the motor with clean, dry, oil-free compressed air when you do your 10,000 mile inspections.

With regards to the motor brush dust causing a ground fault: The DC motor controller is a non-isolated device. So even though it is off, a path can exist from the battery to the motor. This can be true even if a contactor is open depending on the particular circuitry. The best way to determine if this is the source is to disconnect the motor and retest.

Most ground faults I find with EVs can be attributed to the battery pack itself.

Back to the OP question of *DC Motor Maintenance*: There is none required for the first couple hundred thousand miles.........when the build has been done right.


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## crashedup (Oct 28, 2008)

ok well if this is true, why all the fuss about ac drives! why dont we just all stick to dc.
Besides the 5-8% (and im shure im being generous here) of regen braking what other advantages does it have to outweigh the rather large differance in price and power output? Are they that much more efficient? 
What am i missing here?


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## Ziggythewiz (May 16, 2010)

Regen is a big selling point ('cause people fail at math), supposedly AC lacks the full on failure mode experienced by antiquated DC controllers, and it's easier to take a manufacturer/dealer's cut on a pricey AC system vs a cheaper DC drive.


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## JRP3 (Mar 7, 2008)

Plus enough people have had problems with brushes and balancing with brand new brushed motors. Yes they can be very durable, but they can also have excessive problems if everything isn't just right, mechanical commutation introduces extra failure points.


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## crashedup (Oct 28, 2008)

Know body else wants to add anything to this?


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## major (Apr 4, 2008)

crashedup said:


> Know body else wants to add anything to this?


A recent post by dragonsgate showed his 9 inch motor brush at 45,000 miles compared to a new one.









This appears to support about 100,000 miles between service for brush replacement. Here is the source for the photo. http://www.diyelectriccar.com/forums/showpost.php?p=342160&postcount=3


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## Electric Forklift Guy (Dec 13, 2012)

In the material handling world ( forklifts and such )

the stuff we check MONTHLY on DC electric motor


1. Carbon dust building up in the motor , it should be blown out with an air gun about once a month

( wear a mask unless you want your lungs to look like a coal miners circa 1890 )

2. Brushes STICKING in the brush holders or springs getting weak from corrosion/overheat , you should lift the brushes off the commutator to make sure they snap back down on their own. 

3. Debris getting inside the motor , you don't know how many times a customer calls because he "smoked" a motor and it just turns out to be dried out leaves or paper slowly getting cooked inside the motor.

4. Terminal studs on the motor , the insulators can dry out or melt , check the connections and the insulators once a month.

5. Check the bearings for unusual noise.


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## Mr_tim (Dec 13, 2010)

My truck was originally converted in 1997. I don't think it was driven that much between 1997 and 2004 when I bought it. It's been my daily driver ever since and I've put ~80,000 miles on it. I must admit to doing zero motor maintenance in all this time. I now have to pay the price apparently. Earlier this week on the way home the truck started surging a bit. I pulled over and noticed a burning electronics smell. I opened the motor compartments to discover flames poking through the brush screen. I didn't think there was anything flammable in there. I grabbed the extinguisher and doused the flames. I am now shopping for a new motor. I've attached pictures. I don't know if blowing the dust out would have helped or not.

TiM


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## dtbaker (Jan 5, 2008)

looks to me like you wore the brushes down to nothing, one or more dropped out and you started arcing directly to the brush holders.....

good data that is around the 80,000 mile mark. 

I am thinking that annual/10k miles inspection and battery balancing is probably advisable.


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## electro wrks (Mar 5, 2012)

It's impressive that you have 80,000 miles on your daily driver EV. But, in all that time, where you have probably have gone through one or two sets of tires, many wiper blades, other routine maintenance items, and multiple battery sets you didn't think to check or ask about checking the motor brushes? Geeez! For want of ~$100 set of brushes a $1000 or more motor may have been ruined.

May have because despite the negligence, the motor may yet be saveable. Pull it out and take it to a motor shop to get it checked out. While you there, ask them about how the brushes work; and how and when to inspect them.


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## gunnarhs (Apr 24, 2012)

crashedup said:


> Know body else wants to add anything to this?


For Warp-Netgain Series Motor see here http://www.scribd.com/doc/112976633/NetGain-Motors-Service-Manual

Here are also shown brush wear indicators which help determining the status.

As stated brushes should last for at least 2000 hours if temperature does not exceed 100 degree Celsius and holding 2000 RPM. When assuming average speed of 70 km/h (50 miles/h) this would be 140.000 km (100.000 miles).

But assuming driving over continuous power for short time, often RPM over 3000, changing weather condition e.t.c. we have decided to change brushes ("the coals") every 50.000 km (30.000 km if car was stop for longer time as in one case). This has been done both for Series and SepEx -Motors with brushes...
Replacing the brushes should always possible without removing the motor but when changing something more the motor has to been removed and disassembled and cleaned.
So better to change brushes more often, this should avoid more trouble.
We have not driven much further than 50.000 per car so I can not add more info...


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## dtbaker (Jan 5, 2008)

I have not had to replace brushes yet..... 

that document from netgain is a little overwhelming, but very informative. The key info is regarding the wear indicator, and temp snap switch. The wear indicator I am contemplating adding an 'idiot light' on the dash, but it might be too high a voltage for the average LED since it says it is the armature voltage? any comments on that?

my only other comment is that if you drive on dirt roads much, brush wear MIGHT be considerably faster than expected unless you filter the input...


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## zapyourrideguy (Oct 25, 2012)

AC over DC
interesting thread on DC motors and their maintenance. I have 25k miles on my car - civic with 8" ADC motor Zilla controller. lithium pack 144v 180 ah. 
This is the second time that I have scorched a motor. the first time maybe 20k miles ago with a 1231 curtis controller. i chalked it up to the car having been abused by the previous owner (someone had taken the car for a joy ride and flattened the batteries and I presumed didn't t do the motor any good either)
I drive rather gently but my comms looked a little scorched so I cleaned them up with a stone as I have done in the past.
Did that cause my current melted brushes? These motors are supposed to take a lot of amps for short bursts and that is all that I have done and rarely past 500 battery amps, I have no motor amps gauge. Is that my problem? i am an extremely careful person, I am very into this EV thing and yet I still have to replace or repair a 2nd motor.

I am agonizing over my motor replacement - impulse 9 bolts right in or go AC-50 or 51 with the 1239 curtis controller.
If you are not watching all the details, isn't AC a bit better in protecting itself from damage as the controller will go into cutback if it is over stressed? My zilla goes into cutback but the motor is the weak link. I also had an overtemp light on my dash that never lit. The DC proponents say if you do everything right your motor will last 100,000 miles, I guess my problem is doing everything right. 1 more motor and I could have gone AC.
Thanks for any comments or opinions that will help me make the decision.


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## JRP3 (Mar 7, 2008)

I prefer less hassle and would go with an AC system, but since you already have the Zilla maybe you just need a larger motor like a 9.


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## Tesseract (Sep 27, 2008)

zapyourrideguy said:


> ...civic with 8" ADC motor Zilla controller. lithium pack 144v 180 ah.


Motor is too small relative to car weight and battery pack capacity (ie - range) and controller power. You would have much better luck with a WarP-9, but even then I would strongly recommended forced-air cooling of the motor because of the high Ah rating of the battery pack.



zapyourrideguy said:


> I am agonizing over my motor replacement - impulse 9 bolts right in or go AC-50 or 51 with the 1239 curtis controller.
> If you are not watching all the details, isn't AC a bit better in protecting itself from damage as the controller will go into cutback if it is over stressed?


The Impulse 9" would be a better fit, yes. Not quite as strong as the WarP-9, but a drop-in replacement. Don't forget to get the timing changed for the reverse rotation of the Hondas (and, uh, you did do that for the ADC 8" motors, right? Retarded timing is a great way to kill a motor...)

That said, the reason you don't see reports of AC motors blowing up is because the inverters aren't nearly as powerful relative to the motors like in the DC world. Your ADC 8" motor has a 1 hour power rating of 24hp at 120V (implying a current rating of 150A) but you are driving it with a 1000A controller that is rated to deliver at least 300A continuous, or twice the 1 hour rating of the ADC 8" motor. 

In contrast, the HPEVS AC-50 is nominally rated at 71hp peak while the Curtis 1238 has a two minute power rating of 68hp. Needless to say, the 1238 inverter won't be stressing the AC-50 motor like the Zilla will be doing to your ADC 8"...

EDIT: note that I can't seem to find reliable and consistent ratings for the HPEVS motors or Curtis controllers. YMMV, etc.


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## dtbaker (Jan 5, 2008)

Tesseract said:


> Don't forget to get the timing changed for the reverse rotation of the Hondas (and, uh, you did do that for the ADC 8" motors, right? Retarded timing is a great way to kill a motor...)



one other really fast way to kill a DC motor is 'hill holding' at a stop.... you really, really, really do NOT want to use the motor to hold you on an incline at a stop as it will heat the comm unevenly, possible scorch the comm bar that happens to be in contact w the brush.


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## zapyourrideguy (Oct 25, 2012)

Thanks for the comments.
Yes I ordered the motor for clock-wise Honda rotation and then checked it again and checked again when it toasted. It was correct 
and I have a squirrel cage fan that EV source supplied straight over the comms.
I should have had my motor amps limited by the Zilla and obviously a motor ammeter. I have a link 10, a display for my Orion BMS and the analog ammeter for pack voltage that only goes to 400 amps so when i drive if I ever peg the analog meter I let off the throttle.
But if my wife or daughter ever drives the car........

I guess the AC-51 choice seems closer to an OEM solution, more idiot proof.
Unless of course I botch the install. I am really good at following directions, I don't think I could of gotten this far without that trait.


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## honn1002 (Nov 26, 2008)

major said:


> A recent post by dragonsgate showed his 9 inch motor brush at 45,000 miles compared to a new one.
> 
> 
> 
> ...



This brush from my ADC 8 motor at 44K miles compared to a new red top split brush that I'm going to replace with. The motor brush timing is advanced at 6.25 degrees. I could've put another 30K miles on it.


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## honn1002 (Nov 26, 2008)

Mr_tim said:


> My truck was originally converted in 1997. I don't think it was driven that much between 1997 and 2004 when I bought it. It's been my daily driver ever since and I've put ~80,000 miles on it. I must admit to doing zero motor maintenance in all this time. I now have to pay the price apparently. Earlier this week on the way home the truck started surging a bit. I pulled over and noticed a burning electronics smell. I opened the motor compartments to discover flames poking through the brush screen. I didn't think there was anything flammable in there. I grabbed the extinguisher and doused the flames. I am now shopping for a new motor. I've attached pictures. I don't know if blowing the dust out would have helped or not.
> 
> TiM


 Mr_Tim, you've put ~80K miles on that motor that's pretty good. Unfortunately the motor was damaged beyond repair. 

I had the same brush wear failure like that with my first ADC 8 motor. It had only 46K miles on it. The motor brush timing was not advanced. I overheated it 3 times. Every time I accelerated hard I could hear very loud arcing sound from the motor with 750A controller. 

My second motor is advanced at 6.25 degrees. When I accelerate hard, I can barely hear arcing from the motor with the same motor current. The picture below is how the brushes look like seating on the armature commutator at 44K miles. I could put a lot more miles on them, but I had to replace with the new high performance red top split brushes.


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## dtbaker (Jan 5, 2008)

honn1002 said:


> I had the same brush wear failure like that with my first ADC 8 motor. It had only 46K miles on it. The motor brush timing was not advanced. I overheated it 3 times. Every time I accelerated hard I could hear very loud arcing sound from the motor with 750A controller.



hhhhmmmm, no advance, at what nominal voltage? certainly helps explain as ANY arcing will damage the motor rapidly.

as I mentioned earlier, zero mph 'hill holding' will also fry a motor rapidly.


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## honn1002 (Nov 26, 2008)

dtbaker said:


> hhhhmmmm, no advance, at what nominal voltage? certainly helps explain as ANY arcing will damage the motor rapidly.
> 
> as I mentioned earlier, zero mph 'hill holding' will also fry a motor rapidly.



The nominal voltage is 141V. Zero mph hill holding will also overheat the controller.


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## Mr_tim (Dec 13, 2010)

Just a follow up. I may have worn my brushes down to nothing and fried my motor, or it may have been vandalism. On the day my motor caught fire my battery box cover had been removed and not put back on properly. I noticed it and looked around but didn't think much of it. After the fire, I went to security, they pulled the files from the parking lot cameras. Sure enough, somebody went around my truck, opened the battery box and spent a couple minutes under the truck at the motor end. It could be coincidence, and my brushes were old, but...
A few comments on the Warp 9 bolt in replacement... The warp is a little bit longer than the ADC, about .3". The 3"boss on the drive end is tapered on the ADC and square cut on the Warp. My motor adapter (EV America I think) was cut to match the taper and had to be opened up a bit. The non drive end bolt pattern is completely different. 4 5/16th bolts on a 90 degree pattern verses 2 3/8th bolts on a 90 degree pattern that's rotated 10 degrees off normal.
The new motor is in nd the brushes are being worn in as I type... What's the recommended wear in time to properly seat the brushes? I've got it spinning at ~2k at 12V right now. Any thoughts as to how long I should keep it spinning? I'm off to go get the forced air cooling in place. At 12V it's running at about 38C with just the internal fan right now.

TiM


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## major (Apr 4, 2008)

Mr_tim said:


> The new motor is in nd the brushes are being worn in as I type... What's the recommended wear in time to properly seat the brushes? I've got it spinning at ~2k at 12V right now. Any thoughts as to how long I should keep it spinning?


As long as you can. 100 hours is a good target. It helps if you shape the brushes first with a dressing stone or abrasive paper wrapped around the comm. Having higher current while seating helps so spinning the wheels in the air in high gear loads a few more Amps. I use a large battery charger across a 12V battery and see like 60 to 80A. You may need a fan blowing across the motor after a few hours of running. She'll heat up. 

Take it easy driving for the first few 100 miles and check the brushes. Check again at 1000 miles and then maybe once a year or so.

You're looking for a smooth shiny surface on the contact face of the brush and a nice golden gray patina on the comm film.


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## Mr_tim (Dec 13, 2010)

Okay, I'm totally confused right now. I programed the Zilla to 13V and 100 Amps at the motor and ran it for three days. Only 75 hours and not 100, but I'm supposed to be making a presentation at a middle school tomorrow on the electric truck... So, I reprogrammed the Zilla for normal operation, hop in and try to go, keeping everything easy for the first few 100 miles or so. It won't go. The most I'm pulling from the battery pack is 6 amps??? It rolls forward a bit and stalls... Any ideas what might be the problem? The motor is timed for CW and I wired it for CW, it ran for three days CW. I hit the pedal with it in gear and it tries to go forward, so it's trying to turn CW, but it's not pulling any current. Attached is a pretty poor , but legible screen shot of my Zilla Settings. My pack is @75% charge and sitting @159V. I have no clue as what may be wrong. Any help will be greatly appreciated. I'm hoping for something obvious that I'm just not seeing.

Thanks,

TiM


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## dtbaker (Jan 5, 2008)

double check your battery low-voltage limits, you need to set them down low enough so you don't hit them with normal sag under normal loads.

setting the low warning indicator LBVI to something like 2.5vpc x #cells just gives you a warning light if you have it wired up, the setting for low voltage LBV as low as 2.0 vpc x #cells is still fine as it will catch you in time when you are starting to really sag under load, and it flips you into 'limp' mode which is barely enough to get off the road!

also, your motor voltage needs to be set ABOVE your traction pack max to get full power....


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## Mr_tim (Dec 13, 2010)

I've got the LBV set to 130 and my pack is at 160. I left the motor voltage at 150 to take it easy on the new brushes. I'm not trying to get full power, just any power at this point would be good. :-(


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## major (Apr 4, 2008)

Try turning motor Amps up to at least 500.


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## dtbaker (Jan 5, 2008)

Mr_tim said:


> I've got the LBV set to 130 and my pack is at 160. I left the motor voltage at 150 to take it easy on the new brushes. I'm not trying to get full power, just any power at this point would be good. :-(



and, try setting LBVI=120, LBV= 90v


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## Mr_tim (Dec 13, 2010)

Setting the motor amps to 500 did the trick. I guess I don't understand why 150 motor amps isn't enough to get the truck moving... at 150 volts that's 22,500 watts isn't it? It's driving OK now, don't know how the acceleration is as I'm still babying it and will be for a couple of weeks. The kids won't be disappointed at school tomorrow. And I'll be able to park the gasoline powered truck and start driving this one again... it'll be three weeks tomorrow that the fire started.

TiM


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## major (Apr 4, 2008)

Mr_tim said:


> Setting the motor amps to 500 did the trick. I guess I don't understand why 150 motor amps isn't enough to get the truck moving... at 150 volts that's 22,500 watts isn't it?


At launch the motor voltage is quite low. The 150V setting is the maximum motor voltage. At the actual moment of launch, RPM is still zero, so mechanical power out of the motor is zero. It is all about torque. And motor torque comes from current. Just enough voltage is required to overcome the circuit and motor resistance. Once the launch occurs, the motor is rotating and generating a back emf and then is producing output power and requiring increasing voltage as it speeds up.


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## jhay (May 26, 2013)

If comm work has been done on the motor and you want to run it in again to create the patina, can you use your normal high voltage pack and just set the idle feature of the controller or does it have to be a continuous low voltage source like a 12V battery?

John


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## major (Apr 4, 2008)

jhay said:


> If comm work has been done on the motor and you want to run it in again to create the patina, can you use your normal high voltage pack and just set the idle feature of the controller or does it have to be a continuous low voltage source like a 12V battery?
> 
> John


That is apparently what Mr. tim did by setting his controller to 13V maximum on the motor. If, IF, you know what you're doing, yes, you can limit the motor voltage and use the motor controller with the high voltage pack. But, BUT, be careful. Should you mess up and apply high voltage to the series motor, it will overspeed in a heartbeat and burst. So, I advise to use a 12 Volt source. The typical series motor will not overspeed with 12V.

We saw one member, Yabert I think, destroy his custom series motor while tuning his controller due to a simple error sending it to 10,000+RPM with the wheels jacked up.


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## Mr_tim (Dec 13, 2010)

In addition to limiting the motor voltage to 13V, I had my RPM monitor connected and set to 3000 RPM during the brush wear in just in case something else went wrong. The motor spun up to about 2000RPM at 13V. I'm driving the truck very gently for the next couple of weeks to make sure I get the brushes worn in before I turn things back up to were they were...

TiM


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## jhay (May 26, 2013)

Hi Major,

So do I need to set the max motor voltage to a low value or is it good enough to just set the idle rpm? I have tested that on the soliton jr. that I have. I set the idle speed to 1500 rpm and left the max motor voltage at 120V and the controller would happily keep the revs at 1500 rpm. So I guess the question is, would the lower max motor voltage do something better for the process of forming the patina?

Thanks

John


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## major (Apr 4, 2008)

Hi John,

Yabert's mistake was with a Soliton. I take no responsibility for what happens. But I suspect at 1500 RPM, whatever the motor voltage is, DC or PWM, it would do well to seat brushes and film the comm. In fact, 2000 or 2500 RPM may be better  Just avoid 15000 

major


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## jhay (May 26, 2013)

Hi Major,

I'll try it at the higher rpm. I actually started at 500 rpm just to build confidence that the rpm idle function does work.  I used the idle function so that I can put a scope on to get a feel for the electrical noise that the DC-DC converter will see.

I note that you do not take any responsibility. 

John


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## mk4gti (May 6, 2011)

Anyone know the minimum brush length on a Netgain impulse 9 ? Could not find it in the manual


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## dtbaker (Jan 5, 2008)

mk4gti said:


> Anyone know the minimum brush length on a Netgain impulse 9 ? Could not find it in the manual



exactly the kind of specific info we need.... I'm planning to inspect soon, but have no real criteria as to when I *should* replace!


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## Yabert (Feb 7, 2010)

mk4gti said:


> Anyone know the minimum brush length on a Netgain impulse 9 ?


The minimum brush length isn't really the main point.
In fact the brush should be long enough to be sure than the spring apply the force on the brush. If the brush is too small, the spring will enter in contact with the brush holder and will no longer apply pressure on the brush.

I've inspect the brushes in my Impulse 9 few months ago and I've notify two things.
1-All brushes aren't at the same length (despite they was when the motor was new).
2-The life of the brushes of my motor are probably reaching around 70% (only 30% before the end) after only ∼40K km. I guess is caused by the temperature variation from -30°C in winter to probably 100°C or more during summer.


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## piotrsko (Dec 9, 2007)

DONT forget road dust is abrasive as all heck


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## Yabert (Feb 7, 2010)

piotrsko said:


> DONT forget road dust


I used a coverbands on my motor with an air filter, so I hope dust isn't a problem.


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## galderdi (Nov 17, 2015)

I just removed one of my brushes. They are not worn enought to contemplate replacement. But I was surprised that it took a fair amount of force to remove it. I would have expected them to move freely in their channel? 

There is a little oxidisation on the walls of the channel but not excessive. 

Any thoughts or suggestions? My motor is an ADC 9inch.


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## Ziggythewiz (May 16, 2010)

After sitting around for a while mine were all corroded in place. I pulled them all out (unfortunately chipped a few in the process) and cleaned them and the holders as best I could. 

Some still don't move freely though they seem to work decent enough but I bought another set of brushes in case they give me any issue.


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## major (Apr 4, 2008)

galderdi said:


> I just removed one of my brushes. They are not worn enought to contemplate replacement. But I was surprised that it took a fair amount of force to remove it. I would have expected them to move freely in their channel?
> 
> There is a little oxidisation on the walls of the channel but not excessive.
> 
> Any thoughts or suggestions? My motor is an ADC 9inch.


The brushes must be able to slide radially to contact the comm with full spring force without hindrance. Clear the passage in the holder and smooth the sides of the brushes so there is a close fit but no binding or sticking. Stuck brushes will wear to essentially zero contact to the comm and then arc and damage the comm.


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## galderdi (Nov 17, 2015)

Thankyou both for the information. What is the best method for cleaning the channel? Just a dry rag? Or a dry toothbrush? I assume using any cleaning product in there would be a bad idea?


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## major (Apr 4, 2008)

galderdi said:


> Thankyou both for the information. What is the best method for cleaning the channel? Just a dry rag? Or a dry toothbrush? I assume using any cleaning product in there would be a bad idea?


Mild detergent and warm water is ok, rinse and dry. Avoid chemicals and oils. Protect comm surface. Remove end bell, brushes and springs. Toothbrush, brass wire brush, crocus cloth or even small file if needed. Lightly smooth sides of brushes with new abrasive cloth (fine grit) on flat surface. Thoroughly blow with clean compressed air. Do not bother brush face where it touches comm.


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## dtbaker (Jan 5, 2008)

major said:


> Mild detergent and warm water is ok, rinse and dry. Avoid chemicals and oils. Protect comm surface. Remove end bell, brushes and springs. Toothbrush, brass wire brush, crocus cloth or even small file if needed. Lightly smooth sides of brushes with new abrasive cloth (fine grit) on flat surface. Thoroughly blow with clean compressed air. Do not bother brush face where it touches comm.


I get my car back from the transmission shop this week.... they couldn't find anything wrong, so I'm thinking it MUST be the brushes causing the awful bucking and 'clunk' perhaps was the motor mount when motor was bucking.

What are a couple good sources for brushes for a Warp9 ?


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## major (Apr 4, 2008)

dtbaker said:


> I get my car back from the transmission shop this week.... they couldn't find anything wrong, so I'm thinking it MUST be the brushes causing the awful bucking and 'clunk' perhaps was the motor mount when motor was bucking.
> 
> What are a couple good sources for brushes for a Warp9 ?


Check with dealer from whom you bought the motor, or the motor manufacturer, or Helwig Carbon. Post up photos first.


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## Roy Von Rogers (Mar 21, 2009)

http://www.gulfelectroquip.com/technical.php?technicalname=commutator

Roy


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## galderdi (Nov 17, 2015)

major said:


> Mild detergent and warm water is ok, rinse and dry. Avoid chemicals and oils. Protect comm surface. Remove end bell, brushes and springs. Toothbrush, brass wire brush, crocus cloth or even small file if needed. Lightly smooth sides of brushes with new abrasive cloth (fine grit) on flat surface. Thoroughly blow with clean compressed air. Do not bother brush face where it touches comm.


Perfect. Thankyou


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## galderdi (Nov 17, 2015)

I am doing regular maintenance as described in the previous post. But I am still getting stuck brushes due to oxidisation in the brush carrier. Last Saturday I found 6 of the 8 brushes were seized in place. Its not the end of the world as I can pull it apart and clean them every few months. It doesn't do enough milage between servicing to ever start arcing. But it would be nice if the servicing weren't necessary so frequently.

I wonder if this is a symptom of my usage pattern? The motor generally only spins for 2 days each month. Maybe I should be spinning it more regularly just to avoid the oxidisation?

Or maybe it is due to humidity getting into the motor. I wonder if I can wrap the motor in some sort of humidity absorbing product when the motor is not in use?

I also wonder if I can coat the inside surface of the brush carrier with graphite from an old brush? Would this slow the oxidisation?


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## JRP3 (Mar 7, 2008)

I have motors which go unused for much longer periods without any issues.


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## galderdi (Nov 17, 2015)

Ok thanks. So that seems to rule out usage patterns as the cause.
I live in Brisbane which is classified as sub tropical (quite humid). Is it generally less humid there?


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## JRP3 (Mar 7, 2008)

Generally yes.


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## galderdi (Nov 17, 2015)

Ok thanks. Looks like I will need to think of ways to reduce humidity. 
Maybe if I encourage everyone to adopt fosil fuel vehicles that will increase global warming to the point where it cooks off the atmosphere leading to less humidity. Now off to shave my head, buy some gold jewellery and stroke my white persian cat.


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## dtbaker (Jan 5, 2008)

galderdi said:


> I am doing regular maintenance as described in the previous post. But I am still getting stuck brushes due to oxidisation in the brush carrier. Last Saturday I found 6 of the 8 brushes were seized in place. Its not the end of the world as I can pull it apart and clean them every few months. It doesn't do enough milage between servicing to ever start arcing. But it would be nice if the servicing weren't necessary so frequently.


maybe its just too clean. 

seems like a little graphite dust between the brush and carrier would prevent sticking?! maybe a little fine grit sandpaper rub, and leave the dust on when you slip them back in?


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