On 1/26/2015 10:27 AM, Konstanty, Walter (GE Energy Management) wrote:
Guys,
While you are correct that series motors will overspeed if unloaded,
that is assuming there is amperage available but these smaller motors have
enough armature reaction and losses that it's hard for them to do so.....
with that said, don't try it at home... you can damage the motor brushes
or commutator and make it useless.
Running a series motor at higher voltage also increases the speed
proportionately. Fortunately, the lift motor is a simple motor and the increase in
loading will hopefully not exceed the thermal rating of the motor. Smelling
"odors" is probably varnish and not real good on the motor so don't push
them.
I will say it does make the blower go up at a more reasonable clip. And that the smell was probably oil since when I took the motor down I made sure to grease the end bearings while I cleaned up the replaced the brushes (and I smelled it the first time I powered it up, no load).
Heat is an issue, but which is better: 36 volts for 5 seconds to lift or 18 volts for 15 seconds to do the same lift? Likewise the failure mode for lift motors in my life seemed to be shorted armature windings which cause the "chug chug" failure. Not a problem since I went to higher voltages.
I'll take apart the Bill motor and post some pics somewhere on it. If there is one thing I got good at in the past it was fixing lift motors (you can buy the wrong side on Ebay and swap armatures with no problem, converting the right side motors to Elec-trak motors is a bit of a pain but not that difficult).
Chris