With these controllers, it is essential that the field be reversed and that the armature be connected directly to the controller’s B+ and A2 terminals, because the plug diode inside is connected to these terminals. Some vehicles, especially those previously using older, resistor-type controllers, may reverse the motor armature rather than the field winding.
Sent from my iPhone > On Dec 17, 2017, at 1:36 AM, Cor van de Water via EV <email@example.com> > wrote: > > The battery is not the only thing that supplies current to the motor. > The switching of the controller connects the motor to the battery for a > period of time, > followed by a period where the "freewheel" (diode or transistor) inside > the controller > carries all the current, also during the time that the motor is > connected to the battery, > it is not just the battery but also the capacitors in the controller > that provide the current. > Wiring the motor to the contactor instead of to the controller itself, > creates a large loop > and increases the inductance which can affect the operation of the > controller, besides creating > a lot of noise from the high frequent switching and the large "antenna" > loop created by the > wiring conncted to different points. > Some people even twist the motor leads together to minimize the > effective area inside the > loop created by the two motor leads, to further reduce the noise > radiated from the > output of the controller. > especially nearby sensing wires such as throttle control or sensor > inputs can be affected > by hundreds of volts fast-switching nearby and generating large amounts > of noise due to > improper wiring. > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of EVDL > Administrator via EV > Sent: Saturday, December 16, 2017 10:32 PM > To: firstname.lastname@example.org > Cc: EVDL Administrator > Subject: [EVDL] DC controller common terminal > > This question refers to a non-road EV, but I think it's applicable to > road EVs too. > > I recently bought an Alltrax controller for my Elec-trac tractor. Like > most > (all?) DC controllers, it has 3 high power terminals. In this case > they're B-, M-, and B+M+ (actually marked just B+ but described as the > B+M+ terminal). > > The printed manual with it contains the following intriguing warning. > It's printed in boldface type and underlined text (in parentheses, > quotated, capital letters ... no, wait, that's something else). > > "Connect the motor leads as shown, making sure that you connect the B+ > power lead from the contactor and the A1 motor lead AT the B+ terminal > of the controller. This is important for proper controller operation." > > I read this as meaning that I should NOT, say, run a single cable from > the contactor "downstream" side to the controller B+M+ terminal, and > then connect the motor A1 lead to the contactor at that "downstream" > terminal. > > Instead, the motor A1 lead should be extended to the controller B+M+ > terminal, so that there are 2 lugs on that controller terminal. > > View following with a monospaced font such as Courier: > > RIGHT: > |--------------------- > | | > | Motor > B- |M- B+M+ | > |---------() -() ()-------------- > - | > --- | > - | > --- | > |___________________| > > Battery Controller Motor > > > WRONG: > > |--------------------- > | | > | Motor > B- |M- B+M+ | > |---------() -() () | > - | | > --- | | > - | | > --- | | > |___________________|______________| > > Battery Controller Motor > > I've previously connected DC controllers the "wrong" way -- that is, > connecting the motor lead to the contactor when it made for a shorter > motor lead. It seemed to work fine. > > I guess my ignorance is showing here. Can someone explain why > connecting the motor directly to the common controller terminal, not > some other terminal feeding it, would be "important for proper > controller operation"? > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL > Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = > = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not reach me. > To send a private message, please obtain my email address from the > webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)