Is this explaination of field shunting correct?

in article GMJMb.1766$ snipped-for-privacy@nwrddc02.gnilink.net, Nukie Poo @verizon.net>

at vze32jp7 I read the following quote on a electric railroad web site. Is the

It makes perfect sens, but it certainly could benefit from a decent technical editor.

Bill

"Nukie Poo @verizon.net>" I read the following quote on a electric railroad web site. Is the

I was going to post some things about 'shunt' wound DC motors, but now that I re-read this and consider that it's a traction motor, it probably is a series-wound motor. So the armature and field winding are in series, not parallel across the line. In this setup a *large* wattage resistor across just the field winding would work (not across the field and armature in series though). The armature current would be 'split' and some flow through the resistor (I said it had to be large ;-) and the remainder through the field winding.

Motors are often built such that a reduction in field flux will speed them up. The flux going down would normally reduce the available torque, but it also reduces the induced emf in the armature. The result is armature current rises *more* than the flux drops, so the overall torque is higher and the motor speeds up.

Yeah, it's right. But could use a little clearing up.

daestrom

Squared vs double, as I recall. Anyway, re my and DK's thread - tell me about it (clearing up, I mean) :)

Bill W.

Thanks guys