[GreenKeys] 400 Hz MITE Power Supply

[William Wuttke]

I just got my 400 Hz MITE power supply kludged together for testing. It
works well! It uses a EGS002 SPWM Sinusoid Inverter Driver Board (slightly
modified) driving a MOSFET H-Bridge driving an old UPS transformer -
powered by a 12VDC 30 amp switching supply. It draws about 2 amps (DC) at
idle and about 8 amps when the MITE is powered on. Looks like the MITE
draws about 6 amps (x 12 Volts) or about 70 watts which is what the spec
says it should draw from the AC supply. The heat sinks stay cool. Now I
have to get rid of the RFI it generates - probably going to line the Apache
box with copper tape. Apparently, the distortion you see on the sine wave
is due to the voltage regulation of the EGS002 which varies the PWM pulse
width to regulate the voltage. The meter is reading the output voltage
feedback, which is compared against a 3 volt reference for regulation. Now
I don't have to swap out my one 60 Hz motor between printers for
troubleshooting. (The spare (400 Hz) printer needs some work, but will
print out the QBF message.)
73
Bill

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