Hi Rick, Sure you could run a higher voltage battery and set a lower output voltage using an AC controller. It is done all the time when motor speed is less than base. You could set the controller to a maximum motor phase voltage lower than the normal .707 Vb. Or accomplish the same thing by setting a maximum frequency. I am not sure why you would want to. AC motors do not have the voltage limitation seen with the DC commutator.
The 3 phase bridge inverter used as the AC controller can be thought of as 6 Buck converters. Or like a DC controller for each 1/2 phase. So the AC controller has as much control over motor voltage as a DC motor controller. I guess I don't follow your logic with regards to max power, C rating and all that. How would setting an artificially low voltage at the controller output help get more power out of the controller? I wouldn't say that AC lacks flexibility but rather DC is less complex there easier for people to apply to different situations. AC drives require tuning to the specific motor which is often best done by the pros at the place putting the system together. Once that is done the AC drive package is very flexible w/r/t applications and features. Regards, Jeff M ----- Original Message ----- From: "[email protected]" <[email protected]> To: [email protected] Cc: Sent: Thursday, December 27, 2012 2:33 PM Subject: Re: [EVDL] 9" motor Mishap Can AC controllers function as voltage transformers in order to allow the use of a higher voltage battery pack in order to compensate for battery sag that might keep you from achieving max power and holding that power to max set RPM in your controller output. For example a modern 300V input DC controller can easily be set to an output voltage to match a lower motor voltage requirements. 250V in 170V out for a 9". The advantage here would be to reduce battery currents and keep them within their proper C ratings. This way you get every Kw of controller you paid for right up to your set RPM. Does this make any sense or have I missed something? Is there a lack of flexibility with AC or do I just have to plan better? Rick Miller -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20121227/d91a37cb/attachment.htm> _______________________________________________ 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)
