DC Motor Mystery

LOL, I *wish*. No, did 'fast and blacks' out of New London. Had orders to one of the 'B girls' out of Pearl, but that got cancelled at the last minute.

Also did duty on sub-rescue ship (DC propulsion drive and Ship's Service, not to mention some *wicked* towing gear for a particular 'research vessel' [bet you can figure that one]).

daestrom

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daestrom
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Actually a set up similar to what you mention is (or was) not uncommon. The resistor acted as a shunt to decrease the current in the series winding and essentially weaken the series field. This allowed some control of the level of compounding (slope of the speed torque curve). Losses with this resistor in service would be less than with the series winding only. Full series compounding would only occur with the resistor open circuited and the series winding would be a normal series winding.

Use of a higher resistance auxiliary winding with any shunt resistor would be, I should think, counterproductive. However, people have tried many combinations and then went on to design(?) wiring for VW vans.

Reply to
Don Kelly

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Makes me suddenly wonder if this is the type of resistor the OP was talking about. If they 'removed' it, then would have stronger series field, and with differential compound, have trouble with starting. Come to think of it, I'm not positive now that the OP mentioned whether the resistor was strictly in series and the removed the resistor and connected the two leads together to complete the circuit, or if they just 'removed' it letting the series winding carry full armature current.

LOL. Yeah, various folks came up with *all* sorts of things in the age before power-electronics. I still snicker a little and just smile when a younger guy asks me why an amplidyne has so many brushes ;-)

daestrom

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daestrom

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