Bad PN motor?

[HACHI-RYOKU]

I ordered a PN Racing SO2 motor. It came in last night and I pulled it apart to put the armature in a PN BB case. The neo mags inside were corroded and falling apart. Took me a little while to clean up the armature. Anyhoo, I put it in the PN BB case with carbon brushes and a set of new neo mags. I was breaking the motor in and I noticed it getting very hot. I looked through the little peep hole and noticed alot of sparks across the comm (more than usual for the breaking in process) and the motor would go fast then slow then fast again, etc… I threw some comm drops in and it helped a little, but not much. This thing was getting too hot to hold so I unplugged it and waited for it to cool. Plugged it back in with a fresh set of batts and it did it again.

I break my motors in with either 2 AA NIMH or 2 AAA NIMH. Both in this motor’s case. Started with the AA’s and switched to AAA’s. I was also breaking in a Speedy05 w/BB’s and a beat up Anima MM with new brushes at the same time. The Anima wasn’t even getting as hot.

What gives? Shouldn’t this motor be running much cooler? It also seems to lag. Never owned an SO2 before, but it doesn’t seem like it’s running as fast as it should.

[ph2t]

I’ve had this before with some handwounds mate. What I think is happening is that one of the three commutator lugs (where the armature wire wraps around) isn’t conducting to the wire.

Use a multimeter to check that you have a connection. You can do this by checking for a short between each commutator segment. There should always be a short between each adjacent segment…

Also, remove the neo magnets and brushes and see if the comm spins freely in the bb can. MAybe it’s binding somewhere? Posssbly from not being true or pressure on the comm from being too long for the can? Possible but not probable…..

cheers,

ph2t.

[HACHI-RYOKU]

That sounds like solid advice. I’ll definately have to give this a go.

Incidently, I tried something different and it seemed to help some. I shot the motor full of this really good oil that I picked up in Japan. Couldn’t tell you what’s in it as my Kana (writen Japanese) has gone to crap. I remember that it had silicon and a few other synthetic things in it. Real qulaity stuff. Anyways, after the comm drops, I gave this oil a try. I had nothing to loose and it worked great on the stuck door lock down stairs. Well, I sprayed it on the comm first and the motor picked up. I sprayed some more and accidently oversprayed some further into the motor and it picked up some more. So, I got to thinking and I sprayed tons of oil all through the motor while it was moving. It seemed to make it run loads smoother and it stopped getting hot. Now I had a dripping mess of a motor in my hand, so I hung it over the side of the table while it was finishing breaking in and let it drip into a plate on the floor. Kept running real smooth but after 4 or more hours of this the heat started comming back and it started stuttering again. Not as bad as before though.

In retrospec, this seems like a good way to break in any motor and the oil seemed to give the motor more pep than comm drops. Maybe there are better alternatives to the comm drops. Anybody else ever try alternatives to comm drops?

[ken_wyleung]

Some of the PM handwound 35t are OEM by M’z handwound, they are very good. Other PM motor are not very good. If you are looking for a very good motor for your FET car, M’z motor is very good. If you looking for fine motor, Atomic also is a good idea.

[HACHI-RYOKU]

I finally got around to checking this motor with a meter. The com was okay, but the enamelled wire wasn’t. They never took the enamel off one of the positions. It wasn’t passing any juice on one wrap!. So I wipped out the solder and not only soldered all the terminals but also made sure to get the enamel melted at that spot. Runs much better now. I just need to see how it performs in the car.

I also picked up a machine wound 35T epoxy balanced armature from PN Racing and threw it in an Atomic can with neos and CB’s. It’s doing the same thing. I guess I’ll work on that one tonight. I’m starting to loose faith in PN motors. I like there chassis parts but I’ve been having too many problems with their motors.

At least I’m learning about motors though.

[HACHI-RYOKU]

I finally got around to checking this motor with a meter. The com was okay, but the enameled wire wasn’t. They never took the enamel off one of the positions. It wasn’t passing any juice on one wrap! So I wipped out the solder and not only soldered all the terminals but also made sure to get the enamel melted at that spot. Runs much better now. I just need to see how it performs in the car.

I also picked up a machine wound 38T epoxy balanced armature from PN Racing and threw it in an Atomic can with neos and CB’s. It’s doing the same thing. I guess I’ll work on that one tonight. I’m starting to loose faith in PN motors. I like there chassis parts but I’ve been having too many problems with their motors. Something’s telling me epoxy balancing is also not the way to go. The 38T has four gobs of epoxy on it. That’s gotta be slowing the motor down.

At least I’m learning about motors though.

[Dangerous Dave]

“gobs of epoxy” shouldn’t slow the motor down unless rubbing on stationary parts. might very slightly affect the spin up time, but prob not noticeable. The other option to epoxy balancing is by machining the stacks, which can affect the uniformity of the magnetic fields.. but either way a balanced arm is better than an unbalanced one.
The enamel is prob better sanded off at the contact points, to give a a cleaner solder joint.

[HACHI-RYOKU]

Oh, I agree with you. A balanced arm is better than an unbalance arm, but when you’re using 4 gobs of epoxy to ballance an arm with only three rotors then I raise an eye brow. How unbalanced was the arm to begin with? That epoxy has weight. Not much, but it’s enough to rebalance the arm so I’d have to say it’s enough. I don’t think the arm would spin noticeably slower, but I do think it would pull more amps, especially on acceleration, which in turn lowers efficiency. Lower the efficiency of a motor and more of the wattage goes to heat. It’s not really anything to be concerned with unless you’re talking lipos and fets/turbos.

I also agree with the sanding method vs. the melting method but the armature coil terminals on the motors in question are the more fragile type. I’ve broken one before unclamping it from the wire. I’d rather not muck around with them if I can help it.

All in all, PN motors aren’t bad for what you’re paying, but I’ve been having problem after problem with a few of their other motors too. I may stop buying them all together. I still have a hand full that I haven’t fully tested so my opinion might change.

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