[JulsJunior]

Hello All,

I was wondering if someone could give me some pointers on my ADC 9". I'm using it in a garden tractor for pulling. I am not pushing a ton of amperage yet (550 mid track about 650 peak right at spin out), but on my first several passes it seemed to be arcing, possibly excessively.

Here is the video of me pulling it, If you look around my left foot, you can see some intermittent arcing as I go down the track (more towards the end):

http://www.youtube.com/watch?v=GFexW6m4vtE

I pulled the brushes and 6 of the 8 seem okay. However, I'm not exactly sure what I'm looking at. I am no expert with these motors. I could tell you anything you want about an ICE motor tho... Pictures are attached. The two questionable brushes are held next to each other. The pic with the single brush looks like the other 5 (6 good?? brushes total).

Also attached is some pics of the brush rigging, and the commutator. I measured my timing and came up with an estimate of 10.15 deg. advanced. (the two sharpie marks are the two centerlines). Looking at the comm (not touching it!) it appears to be just fine.

This motor has about 400 miles on it when I had it in my Ranger (144v) Running a Curtis 1231C 500amp controller.

I think my problem lies with the brushes. In order to make weight for the next event I will only be running a 120v pack instead of 144v. I think this would help eliminate/lessen arcing as well. However, I still think it should have been fine with the 144v and advanced 10 deg. Let me know what I should do with the brush situation. I have until the 2nd week in Feb. to get everything back together.

Thanks in advance!
JulsJunior

 

[DIYguy]

Hopefully MAjor will chime in. . . however, 10 degrees seems about right for a 144 volt application. Do you know your RPM upper limit and are you hitting it? Also, make sure the brushes are truly advanced... I mean in relation to rotation. The advance needs to be opposite to the direction of rotation....
As for the brushes...maybe running the motor with no load on a 12 volt battery for 24 - 48 hours will help to wear them in some more and develop a good film....

 

[JulsJunior]

DIYguy,
It was probably around 2500-2700RPM at peak. Depends on the run/loading.

The brushes are advanced the correct way as well.

I thought about running it for a day or two on a 12v batt to help get everything back to where it should be. I don't know if that will wear the brush down far enough to get a full contact patch again. Is there anything I can run with it to speed up the wearing in? Will that effect the oxide (film) layer that is on the comm? I just don't know what a truly 'bad' brush looks like, nor how quickly it will wear back into shape with the 12v method. I am lacking experience with electric motors in general. I've read just about all I could on these forums, but knowledge without experience can only get you so far.

I want to get this resolved because I want to push more amperage into the motor (800-900), but I want to make sure it is ready to take that burst of electrons for 12-15 seconds. I'm gona have to get my KW's back in amperage since I'm loosing 24 volts... but I also don't want a 150lb piece of junk at the end of the track...

 

[DIYguy]

DIYguy,
It was probably around 2500-2700RPM at peak. Depends on the run/loading.

The brushes are advanced the correct way as well.

I thought about running it for a day or two on a 12v batt to help get everything back to where it should be. I don't know if that will wear the brush down far enough to get a full contact patch again. Is there anything I can run with it to speed up the wearing in? Will that effect the oxide (film) layer that is on the comm? I just don't know what a truly 'bad' brush looks like, nor how quickly it will wear back into shape with the 12v method. I am lacking experience with electric motors in general. I've read just about all I could on these forums, but knowledge without experience can only get you so far.

I want to get this resolved because I want to push more amperage into the motor (800-900), but I want to make sure it is ready to take that burst of electrons for 12-15 seconds. I'm gona have to get my KW's back in amperage since I'm loosing 24 volts... but I also don't want a 150lb piece of junk at the end of the track...

Major is the best guy to answer this... however... Running it on 12 volts (don't go higher!!) for a day or two will help with the film. It likely won't get through the pitting completely. This is often caused from higher voltage and arcing I think. That said.... under 3000 rpm should not be a problem I don't think. Perhaps you could look into new brushes, there are different compounds some of which may be better for your application.

The motor should also take 800 to 900 amps for this length of time. It is a good idea to use compressed air and blow out brush area after such an event and also to run at 12 volts for a while to re-establish com film. Do you have forced air cooling via an external fan? This would help to clear dust but also to cool down motor if multiple runs are required. I've pushed 1000 amps through my GE for short bursts like this. What kind of controller do you have? and what kind of batteries?

 

[DIYguy]

There is a fellow on here named Jimdear2. He is a tractor puller guy. You need to hook up with him. He has a current thread (and others) on his big 13" motor/puller.

 

[JulsJunior]

Major is the best guy to answer this...

Yea I might send him a pm to glance at this thread. He seems very very knowledgeable.

Do you have forced air cooling via an external fan?

Because of size/weight I was trying to avoid it. I am going to blow all the dust out after every run. I did not do that in the video, which may be the cause of the arcing more than any other factor.

What kind of controller do you have?

WarpDrive 160v/1200amp. I went crazy with the controller because I didn't want to end up with something too small and go and have to buy again. I have the limits set lower right now.

what kind of batteries?

Optima Red Tops 910CA. In the video I had 12 but in order to make weight I'm down to 10

I would like to try and make the same KW number as I did at 144v. (~68.2kw) I think I can do it. Just as long as the motor doesn't mind. I might come up a little short but just so I'm close, I think I will remain competitive. Atleast until I can sell this battery pack and get some Braille AGM's and sell my motor and buy a NetGain Warp9. Should get 160v nominal pack (and make weight!) that I can pull 1000 amps out of. That will get me somewhere in a hurry. Unfortunately I didn't find the Braille's until a month after I bought the Optima's... DANG!

I have been in contact with Jim already. He has been helpful. However, I think Major is the person I need help from atm.

Thanks for the pointers DIYguy!

 

[DIYguy]

Blowing out the dust won't prevent arcing... but it will help to prevent zorching (plasma event) which is the next step. Carbon traces and dust contribute to this.

HAve you considered the Hawker batteries perhaps?

 

[Jimdear2]

JulsJunior,

I had some thoughts, some things to check (I really needd to do these myself during the after paint reassemble). Remember it just like a pro ICE assembly.
Every thing is clean, matched, balanced and triple inspected.

1.) Put a dial guage on that comm and make sure it is true.
2.) Get a spring scale, check the tension of all of the brush springs, make sure there isn't a weak one.
3.) Put all of the brushes into their holders and make sure none of them are sticky. Use the spring scale and make sure the same force is needed to pull them out of theie respective holders.
4.) Clean out the whole area. If needed polish the sides of the brushes with crocus cloth. No abrasives please.
5.) Watch that brush lead routing. No twists or strain.
6.) Is the angle of the brush holders perpendicular to the com on all pairs

I can't tell in the pictures, is that edge chipped and broken or burned)

Major is still your best bet, he may be out of town, he is involved with a couple of competition venues. He usually jumps right in.

Consider force feeding filtered air to boost the internal fan cfm.

A wild thought came to mind a while back, One I just can't follow up on. Oxygen is part of the cause of arcs forming. I suggested flooding the area with a noble gas as a form of expansion cooling and arc suppression. It wasn't laughed out of the forum.

If all else fails find out if there is anyone building race motors (expensive and problematical, who do you trust.)

Jim Husted of high electric was a main man but I haven't heard about /from him in a while.

See the picture below, Hang this sucker on your tractor and go chase mini rods

 

[JulsJunior]

HAve you considered the Hawker batteries perhaps?

I looked at them some. They seem more industrial than high performance.

I can't tell in the pictures, is that edge chipped and broken or burned

Yes two of the brushes (the ones held next to each other) Have chipped/broken/burned edge. I am going to inspect that brush holder tomorrow, and make sure it is holding them square to the comm. The other 6 SEEM fine. But I am not 100% sure what is good and what is bad. Could just those two brushes in bad shape cause all the arcing we see in the video? If so, that would be ideal, and answer a lot questions.

As far as movement and everything goes. The brushes fit fine and move freely, I had no problem removing them. The springs all FELT the same, but short of getting a spring scale on them I can't say for sure.

Consider force feeding filtered air to boost the internal fan cfm.

I would rather not add another component to the tractor if I don't absolutely have to. Plus I would need a larger 12v source battery to run my electronics + a fan. And add a filter on top of that with a little duct work. Another switch and more wiring. All that is more weight, 5lbs is alot right now...

I suggested flooding the area with a noble gas as a form of expansion cooling and arc suppression.

Sounds like it would work, but again its more components/complexity and weight.

I don't see why it can't take 144v and 800-900amps. All I really need to do right now is get this arcing under control and I think I will be just fine.

Maybe I have too much timing for the RPM/voltage I am running? Generally for EV uses, the motor's RPM is almost always climbing. Is it possible that if the RPM is falling with full power applied, the field in the motor does some weird stuff and that is causing the excessive arcing? The arcing seems to be worse towards the end, which is when its getting harder to pull and thus loosing RPM... I really have no idea what I'm talking about but it sounds good to me lol

 

[DIYguy]

Some good ideas there fro Jim. When looking at gases, I'd only look at two of the noble gases. Argon and mayyyyybe Helium. The others are either too expensive or dangerous. I think being "noble" isn't the most important point, but as Jim mentions, the displacement of oxygen will help to keep the arcing more local. The cheapest and most readily available is likely Argon. (welding supply store)
I don't know of anyone trying this..but why not....?

I've heard of ICE guys blowing off CO2 extinguishers to cool down intake air or intercoolers.... lol

I actually sprayed my entire inner brush holder gear and surrounding area with insulating varnish. It has an insulating value of 2100 volts per mil. I didn't get the best review when I brought this up a year and half ago or whatever it was.... but I later found out that some of the racing guys have done it/do it. The one argument was about shedding heat... or the possible thermal insulating effect. I think it's too thin to matter. I used Crown 6084 Rated Class F and flexible.

You need to focus on the brush arcing though... and if you don't find any issues with springs you may just want to look at different brushes. 3000 rpm and 144 volts with 10 degrees advance should not result in much arcing. I went 13 degrees on my GE, but that was for 192 volts. (limited to 160)

 

[JulsJunior]

Do you know of any sources that have different compound brushes for the ADC 9"?

I've heard of putting heavier springs in (twice the stock strength) to control the brush better. It increases wear but I could really care less (just as long as the dust is kept down by a better/harder? compound brush).

If I had to bump it a couple more degrees timing to solve the issue I wouldn't mind terribly. Give up torque<Zorch. Of course now I'm going down to 120v so I might not need to change anything and the arcing will lessen to acceptable levels.

 

[Jimdear2]

Yes two of the brushes (the ones held next to each other) Have chipped/broken <snip>/Maybe I have too much timing for the RPM/voltage I am running? Generally for EV uses, the motor's RPM is almost always climbing. Is it possible that if the RPM is falling with full power applied, the field in the motor does some weird stuff and that is causing the excessive arcing? The arcing seems to be worse towards the end, which is when its getting harder to pull and thus loosing RPM... I really have no idea what I'm talking about but it sounds good to me lol

One thing we have all missed here. Call the manufacturer, find out what the engineers recommend, maybe just a different brush material, maybe heavier spring . . .

Could be a simple answer

Another question, how did your motor end up already advanced. Did you order it that way? I'm very inexperianced here but I thought motors were wound to a voltage/current/rpm specification and brushes were neutrally timed so rotation could be reversed and advancing was a field expediant.

Jim

 

[DIYguy]

I talked to two places when I was looking to replace mine. Jim Husted, and these guys http://www.manvillemotor.com/

I ended up getting OEM spec'd brushes locally.

 

[DIYguy]

By the way... congrats on that tractor! That's some awesome pulling for your first time out! (or anytime) I'm no pro like Jim, but I actually know what is going on there. I was part of a pulling team many years ago with a Chevy big block in a 6000 lb econo class. We had a lot of fun then too! (but I always like the little ones...electric is the way to go!)

 

[JulsJunior]

Another question, how did your motor end up already advanced. Did you order it that way? I'm very inexperianced here but I thought motors were wound to a voltage/current/rpm specification and brushes were neutrally timed so rotation could be reversed and advancing was a field expediant

I honestly don't know, when I converted my ranger in '08 I ordered the motor from evparts.com and it arrived like that. Which was good, because at the time I had no idea about brush timing or none of that stuff. So happenstance worked in my favor. Unless it is technically neutral timed now... But I think the 400 miles @144v in the Ranger would have done some hefty damage to the motor if that were truly the case.

congrats on that tractor! That's some awesome pulling for your first time out!

Thanks! I was actually thinking I was going to be over-geared based on the torque sheet I had and the calculations I did, turns out I was undergeared! So that is a big relief (I couldn't gear down any farther without redesigning half the tractor...). Guess I underestimated the torque these things make.

electric is the way to go!

Once you get hooked, its hard to not mess with anything you can put batteries and a motor on!

 

[Jimdear2]

By the way... congrats on that tractor! That's some awesome pulling for your first time out! (or anytime) I'm no pro like Jim, but I actually know what is going on there. I was part of a pulling team many years ago with a Chevy big block in a 6000 lb econo class. We had a lot of fun then too! (but I always like the little ones...electric is the way to go!)

DIYguy,

Thanks for the PRO comment, but JulsJunior is the PRO here, He's just starting a new direction and getting his feet firmly planted. I think he actually makes money at this, at some level.

Me, I'm just an enthusiastic amature having fun and spending money.

Jim

 

[DIYguy]

I believe the ADC motors come advanced already. You can do a quick visual by eying up the center of the brushes with the pole shoe mount screws on the frame. If they are dead in line... it's neutrally timed. It should be 10 degrees shifted against (opposite) the direction of motor rotation.

Did you say you had a tach? Have you verified it?

 

[JulsJunior]

You can do a quick visual by eying up the center of the brushes with the pole shoe mount screws on the frame.

Yea, in the pics of my first post it is, if you look at the end bell I have two sharpie marks showing the two centerlines.

Did you say you had a tach? Have you verified it?

Nope, I don't have time to look at that going down the track

 

[DIYguy]

Nope, I don't have time to look at that going down the track

Ya, I hear ya...but you may be turning a lot higher RPM than you think. (Maybe this is part of your gearing dilemma...?) Do you have a tacho-generator and if not how do you control RPM?

Perhaps a large dial somewhere in your sight-line would be helpful? Something you don't have to actually "look" at...but can still see.

 

[JulsJunior]

you may be turning a lot higher RPM than you think.

I'm pretty confident of what I'm running. Attached is a spreadsheet with all of my possible gearing ratios I can do (hopefully you can open it). Just play with the RPM value and look at the MPH in column 'F' (That was my 'High Gear' in the video's, 'Low Gear' would have been Column C). If you watch my second run, You can see that the tires are hooked in very well. I would give it 3-4mph of slip/squat. Giving it any realistic amount of slip (and squat), you are still looking at an RPM value of right around 3000 RPM +- a few hundred RPM. I wouldn't think 3300 would (worst case realistic scenario) not be that high for this motor. Now if it were near 4000 I could believe we might see some arcing.

My tentative re-gearing ratios will be Column F, H, J, L (16,18,20,22 Top Shaft Tooth Count) This will def. drop my RPM (along with the loss of 24v...) But this should allow me to throw some amperage at the motor. And hopefully go faster. Not sure what RPM range I am looking at to get 800 amps into the motor with 120v source (minus voltage sag...) Again, I just don't have enough experience with this motor to even get a ball park. I know 20% loss of Voltage=20% loss of RPM. Which would make even more sense to gear up (to try and maintain my previous MPH). I just need to make it up with amperage.

I could share a spreadsheet of the logged Data from my runs (I didn't record the third run, I was too giddy and just wanted to pull ) If you think that would shed some light on the situation I can upload those when I get home from the shop.