My GE EV-100 / EVT-15 controller does something similar using the battery contactor and the motor contactor: Before closing the battery contactor it will check pre-charge and battery voltage, then it will close the battery contactor and check the motor output, which is attached to a pair of identical high value resistors, one to battery + and one to battery - so that the open motor output should be at 50% battery voltage unless either the IGBT is leaking to - battery or the flyback diode is leaking to + battery. If the motor output is not too much from a mid voltage, then the motor contactor will close and the controller can drive the vehicle. During operation it will also monitor for overcurrent and limit the current, but if the IGBT shows de-saturation then it assumes a short circuit is happening and it opens the contactors. Note that this has prevented several run-away cases or blowing stuff up when one component failed.
Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info http://www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV Sent: Monday, February 01, 2016 12:41 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Juicebox contactor problem Cor van de Water via EV wrote: > I am sure that this test is done in software just to verify that > everything works, just like there is a special relay that will > *create* a GFCI event just to test the detection of GFCI before > relying on it. Most standards actually do not specify what happens in > transition (such as power up) I agree. It is common practice for a product to test its own safety circuits automatically, one way or another. The standards were written to allow and even encourage this. Relay contacts can stick closed. If you want to be sure a relay opens, then monitor its contacts and operate it. I recall one product where it was vital that its AC output could be turned off in an emergency. So we had *two* relays, with their contacts in series (one switching one hot lead, the other switching the other). The safety test circuit closed and opened one relay while measuring its output to be sure it worked. Then it repeated this test with the other relay. Only if both passed did it turn on BOTH relays to power the load. -- Knowledge is better than belief. Belief is when someone else does your thinking. -- anonymous -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ 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 Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
