On 1 Jan 2018 at 10:03, evdragracer--- via EV wrote: > An HTML attachment was scrubbed...
The scribbed attachment (html) is below. To prevent this in the future, please send only plain ASCII text. ===== I have 2 sepex vehicles. A circuit diagram might be clearer, but hopefully words work OK: On my tractor: Keyswitch turns on field relay field relay hooks up field to a 12V battery The field lead is wrapped around a proximity reed switch (used in alarm systems to see if a door or window is closed, the switch changes state when a magnet gets close enough to it). The wraps of wire provide the "magnet" to close the reed switch. Current in the field closes the proximity reed switch The proximity reed switch turns on a contactor relay that feeds the armature through a big, high power current limiting resistor The proximity reed switch also feeds a delay relay After about 1 second the delay relay feeds a contactor that shorts the current limiting resistor Don't forget to put a big diode on the field, otherwise you'll get a big arc when you shut off. It is amazingly smooth, I can start in gear and the tractor takes off very smoothly. Idle RPM is about 3600 rpm. I get regen down hills. The tractor has a variable speed transmission so I don't need to change motor speed. If I did, I would put in a welder rheostat in series with the field. I also have a car with a sepex. It has a Kelly 144V sepex controller. The controller needs to have been ordered with the appropriate current range for your field. My first motor had low field resistance, the Kelly worked well for that. For my new higher resistance field motor, I can't get the Kelly field current to go low enough, so I have to run in "Voltage Mode" for the field, which means no field weakening. It still works pretty well, but that cuts off my higher RPM. If I could get to the field current sense resistor I could fool it to work at lower field current (it's potted, I'm reluctant to remove the potting compound). 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)
