On Fri, Nov 7, 2008 at 10:57 AM, Tom wrote: > The common problem I see with a current sensing load it the initial turn on > transient. Since the power supply output is zero the MOSFETS are driven into > saturation. Depending on the response of the load and the protection in the > supply this can create some interesting problems. Crowbar protection on a 4 > kW supply or a 20 kW inverter for example. The better loads allow for slew > rate control and constant resistance modes that help some. Interesting. Last time I was in a power electronics lab and the electronic load we have are only for lower power. So when we needed to test bigger converter or inverter module (up to 5KW), then we had to use a big bank of resistor with fans for cooling. I also saw people using a bank of lamps as load. Very good heater in Winter time. But in summer time, oops. I am thinking motors can be useful for higher power load as well. Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist