SOunds like the sensor lost its hysteresis (shutting off at one pressure and resuming at a lower level but instead, senses constantly, so as soon as the pump quits it restarts the pump. That, or the pump lost seal, so the pressure drops as soon as the pump stops and the sensor responds by restarting it. If there is no way to open it (and get it back together) then running constantly sounds like next best thing. Some pumps are run at lower voltage to reduce stress, but I think that mainly is done for power steering pumps. Maybe use an external sensor on the vacuum storage, which will control the pump that is set to run continuous?
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.com Skype: cor_van_de_water XoIP: +31877841130 Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 -----Original Message----- From: [email protected] on behalf of Adrian DeLeon Sent: Fri 9/27/2013 1:36 PM To: [email protected] Subject: [EVDL] Vacuum pump question/issue I've got a 7 year old MES-DEA vacuum pump that no longer shuts completely off. After pumping down, the pump begins to quit, but then starts/stops rapidly, sounding like the lope of an idling (very quiet) race car engine. I checked for vacuum leaks, disconnected and plugged various hose ends, and finally plugged the end of the pump with my finger. In all cases, the pump would stutter after reaching its preset vacuum level. Now for the big question: Do I leave it the way it is? Or do I put the pump into its "continuous run" mode? My thought is that running constantly would be better than the constant start/stop, which is probably stressful to the motor and its drive electronics. This particular model has a built-in pressure sensor that gets bypassed if the polarity of the pump connections are reversed. Ideas? Adrian _______________________________________________ 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) _______________________________________________ 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)
