Re: (ET) Elec-trak snow thrower performance

[Christopher Zach <czach computer org>]

Rob Brockway wrote:
> Yep.  I think Bill told me there were three motors.  Early one was a 
> series with speed limiting winding.  Without the speed limit, the motor 
> would try to go 9000 rpms, very unsafe.  The series winding gave it 
> great starting torque.  The motor with special windings behaved like an 
> IC motor.  Later models were shunt wound with a spring on the 
> tensioner?  One thought is that it provided some motor rotation at start 
> up, so the shunt wound could work with its reduced starting torque.  I 
> tested the motor with and without the speed limit winding.  The shunt 
> winding alone consumed significant amps (6.5 amps ?).
> Rob

Hm. I would be interested in finding out which motor I have. They could 
not have used a pure series motor on either the tiller or the blower as 
they would ramp up to infinite speed if you ever broke the chain or the 
tiller belt. Given that I have broken a tiller belt once (well, it 
slipped) I can say that's not the issue.

They must have a small shunt field on the inside to keep speed down just 
as the Elec-trak drive motors have a little series field to get things 
going.

I must have a series as the torque is incredible, and it pulls all the 
power when starting up. In fact if the lead batteries were low it would 
pull the voltage so low the contactor would drop right out.

Chris