On 13 Feb 2015 at 12:20, Lee Hart via EV wrote: > A further complication is that the Curtis pots are weird. Instead of a > resistance track that covers the full 300 degrees of rotation, they had > it printed on only about 90 degrees, with solid metal for the remaining > 210 degrees.
The old PMC potbox I had did NOT do this. It had a conventional potentiometer inside, and a tricky mechanical linkage with two pulleys, a spring, and a steel cable. It was rather like the dial cord on an old table radio. The linkage converted the actuator arm's 90 degree movement into the control's 270 degree movement. I still have a copy of the manual for that old DCC96 controller, including a full schematic. It does indeed show the potbox connected with 3 wires, including both ends and the wiper. Regrettably I do NOT recall the model number on the potbox I had. I've run another another style of Curtis potbox, which has a microswitch externally mounted. The switch was used for controller disable at zero pedal, IIRC. Maybe some PB models had that mounted internally and connected to a third wire. To identify such a setup, you'd use the ohmmeter again, looking for a pair of wires that switched from zero resistance to infinite resistance (or vice versa) almost straightaway when the acuator lever is moved off the zero stop. Or you could take it apart. ;-) 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 For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
