DC motor Operation – Q&A

[Sub MandrelParticipant @submandrel]

How about one of these:

(Actually I think it's the AC sychronioser control of a power station).

Neil

[Harold Hall 1Participant @haroldhall1]

If you have access Andrew to early copies of MEW you may find my series on electric motors AC and DC help. The series started in issue 15 with issue 16 devoted to DC motors and issue 18 to speed control of dc motors.

If you do read issue 15 then I made a major error reagarding star and delta contections, I typed in star when it should have benn delta, or the other way round. I still get nightmares about it.

Sorry but the theory is now well and trully lost in the mist of time so cannot easily come up with any answers.

Harold

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

In college and early days in industry there was still a lot of old mechanical and electrical equipment around and often still in use .

Most of it was relatively safe but there were plenty of death traps as well – newcomers might like to read about that mine power house on earlier thread .

Sadly within ten years almost everything old had disappeared either altogether complete with factory buildings or had been replaced by rather dull square boxes .

Other things than series wound motors can run away under no load – gas and hydraulic turbines are well known examples .

Anyone that likes pondering electrical matters might like to explain how a self excited shunt wound DC generator ever gets started .

MikeW

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by MICHAEL WILLIAMS on 14/09/2013 13:29:22:

Anyone that likes pondering electrical matters might like to explain how a self excited shunt wound DC generator ever gets started .

Residual magnetism in the core?

Russell.

[Anonymous]

I'd expect it to give itself a stern talking to, get off its backside and start at the beginning; which is precisely what I'm going to do, back in the workshop.

Andrew

[jason udallParticipant @jasonudall57142]

Neil…Hawkwind..
.looks morw like Kraftwerk

[MuzzerParticipant @muzzer]

Presumaby a self excited shunt wound DC generator is what we would have called a "dynamo" in old automotive parlance. In which case, yes, it was down to remanance. Some vehicles had positive earth systems didn't they, in which case you had to magnetise the machine in reverse if you wanted to change the system or dynamo to the other polarity.

Muzzer

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