Heisler motors

[badlydrawnroy]

I'm in the process of converting my Heisler to radio control using a Crest receiver/controller/sound unit.  When I run for more than a few seconds it registers an overload- something that has never happened on my other locos (including a 3 truck Shay which, with 3 motors, should draw more current)
I dismounted both trucks and tested the resistance of the drive circuits including motors: They register 7 and 8.5 ohms respectively (which at a typical running voltage of 10v would draw 1.1 and 1.7 amps respectively). I presume that they should both be he same, but 2.8 amps seems a high current drain and explains the overload.  Does anybody know what the resistance/current drain should be, and what I can do to get it down to an acceptable level?  My first thought is problems in the motors, but replacements are not available on the parts list on Bachmann's site.  I'm based in the UK but Bachmann Europe have no stock either.  All suggestions welcome!

[Loco Bill Canelos]

HI Roy,

Strange situation.  It would be highly unusual if both motors were bad. My Heisler drew just over a half Amp while running light, and slightly higher when starting.  Are you running on battery power??  I was wondering if your Heisler ran OK while on track power?  Also wondering if you broke it in before the conversion?? and if the current draw was the same under track power??

You could try re-lubing the trucks and running them on straight track power to check if the current draw before the conversion was the same.  Also be sure to check if there is any binding in the mechanism.  If you are not on battery power try some conductive lube on all the electrical contact points.   If on track power recheck the track to see if there are any bad joints or other issues that might contribute to the problem.  I can't think of anything else right now.

I know this is not much help, but it can be hard to diagnose from afar.

Loco Bill

[Greg Elmassian]

You really cannot use the static resistance of a motor to determine it's running current. A motor is a complex situation of inductance and resistance and load.

Test the current draw when running light (on rollers) and actually moving itself, and then with a load.

Greg

[Tony Walsham]

As happened around the time the Heisler was made Bachmann, were using an early method of motor "noise" suppression with 47 mfd electrolytic caps.  Occasionally they were incorrectly applied to the pcb.  The loco would run correctly in one direction but not in the other direction.
It would be beneficial to remove the pcb's from each truck.  Not an easy task, but does solve the problems.
Other locos affected that I know of include:
The Spectrum 4-4-0, 2-6-0 and Connie.
Later locos had a different, very successful method of suppression using RF chokes and 3 x .1 mfd non polarised monolith caps.