Drewcifer wrote > I thank you for the link am I have read it twice and as a non scientist I > don't understand how it applies to the below information suggesting that > pmdc motors should not be run in parallel. I apologize for my ignorance. > ...
I really don't know how else to explain this without repeating what I, Lee Hart or Bill Dube have already wrote. Put as simply and succinctly as possible, PMDC motors have a fixed and fairly "stiff" relationship between voltage and RPM, and because no two motors are exactly alike, no two motors will have exactly the same Volts/RPM ratio (usually referred to as "Kv"). Thus, unless both motors are allowed to spin at different RPMs, the motor that spins faster at a given voltage will hog all the current, with some of that current coming from the external supply, and some coming from the other motor (acting as a generator). This is pretty much bad news no matter how you slice it, hence, the advice to not drive two or more PMDC motors from one controller. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Series-and-parallel-switching-tp4661043p4661183.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
