--- On Fri, 12 Jun 98 08:37:00 EST Richard Cass <[email protected]> wrote: > We want to do ongoing testing of an ITE product (here in the US) on 220 > VAC > 50Hz power to simulate the European environment to make sure our power > supply vendor is doing his job. In this esteemed group's experience, > what > is best (i.e easiest, cheapest, most reliable) way to set this up. I > have > an electrician describing scenarios of a 60Hz electric motor > mechanically > driving a 50Hz generator. In this age of high power solid state > electronics, I gotta believe there's a better way. Please keep answers > simple as I am only a lowly mechanical engineer (analogies to water > running > through pipes always is always big help to me). At 120VAC our products > pull 6 amps peak at start up and only 3 amps running. I would never > test > more than 4 products at a time. > > Thanks in advance for the usually invaluable help that I get from this > group. > > Richard Cass > Iris Graphics, Inc.
Richard: Have walked a kilometer in your shoes for both 50 Hz and 400 Hz. There's good reasons for both a MG and an electronic converter solution. I was often able to buy a MG surplus, especially for 400 Hz. A good MG set will last forever, sitting forgotten in some back room. Just push the remote ON/OFF in you lab, and its ready to go. The MG is very forgiving of accidental overloads, and the rotating mass carries you through short overloads very well. The isolation is excellent; you don't have to worry about garbage on the utility lines and YOU define the grounding. Harmonic and spurious content is very good, and RF emissions are zero (except for some units which have sliprings for a DC exciter winding). The MG drawbacks are mechanical noise and vibration. Also, the MG is very inflexible. If you ever need to do voltage/frequency sag/surge or cycle dropout, then the MG is the wrong choice. OTOH, maybe the economics are changing. Our plant cut over to an electronic 60 Hz to 400 Hz converter last year, after many years of running a BIG MG set. I don't know what size this unit is, but it must be in the 50 KVA region (I have a 208V 20A 3 phase feed just for my lab). Of course, this is just utility power; there's no capability here to do any voltage or frequency programming. In the last 9 months, the electronic system has given us no problems. Ed -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 06/12/98 Time: 09:24:49 --------------------------
