Re: surging, motor

["David Roden" <roden ald net>]

Date sent:              Sat, 02 Jan 1999 22:27:21 -0600
From:                   Christopher Meier <Christopher Meier cwix com>
Subject:                surging, motor
To:                     elec-trak cosmos5 phy tufts edu

> Occasionally,
> when starting from a dead stop, the motor fails to go, even
> though all contactors clack and power is given to the motor.
> I reach down and turn the motor pulley just a bit by hand,
> and then it works fine.  I expect that I need to check the
> motor for servicing, but if I delay for a bit, am I likely to
> toast the motor?  

Your starting torque should be much higher than that, even with friction 
in the motor (which could be high brush pressure but I'm afraid is more 
likely to be rough bearings).

That's a wound field motor, not PM, right?  I think in the late model 
range the E-16 had a wound field.  If so, check the field connections and 
make sure the field weakening relay isn't stuck.  If it doesn't get full 
field voltage when starting, that would cause low starting torque.

Whether it's harmful to keep going like this depends on how much you use 
it, I guess.  Motors are pretty expensive; I wouldn't take the chance.

I speak from general EV experience, not much specific ET experience 
(since I've had one only a few months), so someone with more specific 
experience may be able to help more.  Good luck.

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