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Fun with industrial VFDs

4311 Views 2 Replies 2 Participants Last post by  PStechPaul
A long time ago I bought an IDM "PowrMaster" VFD, 480V at 9 amps, which never quite worked, and now I am stripping it for parts and maybe repurposed for a DIY inverter:

It appears to be 3.7 kW (5 HP) and with all the panels and parts (not all shown) it probably weighed at least 40 pounds. The IGBT module is a Toshiba 6D130A-120 1200V 30A with an extra free-wheeling diode, and there was also a QM30E3Y-2H 1000V 30A Darlington module that may have been used as a precharge controller. There are two 1000 uF 400V capacitors and some ceramic resistor modules used as bleeders and gate drive resistors. The bottom is a huge flat heat sink:

Meanwhile, I had a newer Toshiba H3 7.5 HP 460V VFD that was supposedly working, but I never tested it except to see that the LCD display came on:

This should be the manual for it, but I'm having problems downloading it now:

And it's available here:

I was able to go through some of the various (highly complex) programming steps and everything seemed to work as it was supposed to, except, when I try to "RUN", I don't get any voltage out of the drive. I am putting about 500 VAC into L1 and L3, and the DC bus reads about 460 VDC, but there appears to be no AC output at all. There are no errors showing on the display, and I didn't see any sign of damage or loose connections and such in the drive when I disassembled it further.

I was really hoping this drive would work, and I am still wondering if there may be something I have overlooked in the setup or the way I have it hooked up that keeps it from doing anything. It appears to be serviceable, and it would probably be not terribly hard to get to the IGBTs to test them. I paid well under $100 for this drive so I can't complain, and I hope I can fix it so that I can use it as-is, rather than gutting it and rolling my own. I'd still like to do that, but with the old IDM. It's amazing that this 7.5 HP drive is only about 25 pounds.
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Don't know exactly where you are at, but well pump repair places know these units here.

Pictures of the whole deal including motor would have helped.

Most of the stuff I have seen needs a safety switch close before moving pot wiper. The manual alludes to that in the wiring section.
I finally figured it out and am now spinning a motor. Here is the video:


I was surprised how hot the motor got, running with no load, but it may have been because of the low speed not spinning its fan well enough, and also possibly from the V/F algorithm, which was set for some "boost" at low speeds. ;)
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