10 replies to this topic

[timtulip]

Hi folks,

within a week, 2 of our cars with FF 18000rpm motors died. One was a new Renault F1. The other was a 2 month old, barely used MK1 Escort.

Both motors seized.

Any known faults? Is this a common problem?

[munter]

I have never heard of a faulty ff motor except.....the one I munted while fitting a pinion.

However with a million made some must be due to fail.
Are you sure you haven't shorted something out in the system?

regards

[timtulip]

How did you stuff one up fitting a pinion??

One of the motors blew on the home track, the other out on a routed track. The cars looked fine on inspection. Nothing wrong with them i don't think. Both motors did the same thing, seized up. Strange.

But as you said, some must be duds after so many made.

[munter]

Quote

How did you stuff one up fitting a pinion??

I was pushing a slotit pinion on using a benchvice.
The necessary shaft sleeve pushed the motor bearing back into the motor !!!

I have done this successfully a few times now ....
...... it gave me a reason to open the motor up and have a look though.

Check the drive end bearing is still in place on your motor.
Once these motors are stuffed, that's it, get a replacement

regards
munter

[kalbfellp]

Quote

seized up

Have they seized up OR thrown some windings inside the motor? What sort of voltage were they running on? How many magnets OR how much weight in the car?

[SLOTJOCKEY]

kalbfellp, on Aug 10 2010, 09:33 AM, said:

Quote

seized up

Have they seized up OR thrown some windings inside the motor? What sort of voltage were they running on? How many magnets OR how much weight in the car?

How do you open one of these up. I thought they were a sealed unit. I had one die on me when we were racing magnet sleds. Damn it was quick just before it expired.

[timtulip]

There were 2 standard Scaley bar magnets in the Escort. There was only 1 standard scaley bar magnet in the F1.

I haven't inspected the motors since they died, so i wouldn't know if its the bearings.

If magnets were the issue, how do people run a few magnets for open class cars without cooking the motors?
Eventually i'd like to have a car in open class, but i don't want to cook motors!

[chenglaw]

I had something similar happen to me with my Scaley Ferrari F1 a few years back. Complained bitterly about it in one of the forums. Adrian Norman emailed me and asked me to send the motor to him to have a look. I did that and it didn't take him long to write back to tell me what had gone wrong. All Scaley motors are fitted with a capacitor (that little brown round blob with 2 wire legs soldered to the motor's brush ends). Usually, after the capacitor is soldered to the motor, it is bent over the top of the motor casing and a piece of masking tape is stuck to the top of the casing to prevent the bare wire legs of the capacitor from touching the casing and shorting out the works. In my case, the masking tape had shifted and the wire legs got in contact with the casing - result: a short circuit and motor stopped working. Adrian just simply moved the masking tape back to its original position which removed the short circuit situation and everything was back to normal. Man, did I feel like a right twit for not having spotted something as basic as that! The only consolation I had was when the motor was returned to me, Adrian also sent a couple of spare ones which he had pulled out from some MotoGP bikes, bless him.

[timtulip]

timtulip, on Aug 11 2010, 04:19 PM, said:

If magnets were the issue, how do people run a few magnets for open class cars without cooking the motors?
Eventually i'd like to have a car in open class, but i don't want to cook motors!

anyone??

[chenglaw]

timtulip, on Aug 19 2010, 11:54 AM, said:

timtulip, on Aug 11 2010, 04:19 PM, said:

If magnets were the issue, how do people run a few magnets for open class cars without cooking the motors?
Eventually i'd like to have a car in open class, but i don't want to cook motors!

anyone??

I don't think there is any magic formula for that. Running a car with heavy magnet traction will cook any motor eventually. The aim is to find a compromise to give the amount of traction you need for about as long as the race will last. If you are thinking of running a heavily magnetised car all day long - forget it, that's in the valley of dreams! Unless you change motors after every race or two.

[munter]

From memory my magnet maximum was a ninco mosler with seven magnets strategically loaded with 750 grams(approx) downforce showing on a magnet marshall.That last figure is from memory.The car had an NC6 and prorace hubs and gears with lots of chassis bracing.It was a solid performer on Ninco track.

There was a turning point for me when a fellow club member showed up and pulled the trigger to the max as his mosler rocketed around the track.
The controller was on max,the car didn't come out and he wasn't even watching but talking with some others.......magnets? who needs them?
I went back to wood after that. I repeat...back to wood!

The motor(NC6) is now powering a scratchbuild 1/24 BRM (thats the 60's GP BRM) The motor got warm but never hot as it was always running in its upper rev range and didnt seem to be loading up ....the finger was hard down.....again from memory a 15 OHM Parma turbo controller worked well or was it a 4 OHM???

regards

ps on the same track I saw a few cars run like the wind for a while and then become slow as the motor heated up and had trouble with the magnet load.