Inverter compressor tester

[RBM]

Just wondering if any body has tried to use a variable speed drive (VSD) to run aircon inverter compressor? Have seen a few 240 volt single phase to three phase ones but voltage may be to high.
Interested to know if its been done as it would be good to be able to test these compressors

[nike123]

That depend on compressor motor type. If it is DC inverter, then it can be run only with dedicated electronic circuit. If it is AC inverter than it is ordinary 3 phase compressor and with right VFD (variable frequency drive) can be used for testing purpose.

[Tayters]

I bought a small inverter for the same reason a few years back. Only tried it a few times on small splits. Each time I got the compressor to run but it didn't half shake about. Always put it down to the fact the inverter was too small for the compressor but actually might have been for reasons as Mr Nike suggests.

Cheers,
Andy.

[RBM]

Thanks for replys, my understanding is inverters turn single phase AC to DC then create an AC three phase at about 200 volts - just thought it would be good to be able to test for seized compressor etc, any ideas as to how else this could be done? (without risking a new inverter board)

[nike123]

Motor can be checked with Megaohmmeter (Megger) for insulation faliure (only to housing) and with Milohmmeter (Wheatstone bridge) for major windings shorting (comparing resistance) . Other than that, without applying power, nothing can be tested more.

AC inverter board can be checked by connecting 3 indentical and strong enough light bulbs in delta configuration and than measuring voltages and amperages wich Inverter board is producing. Also, there are inverter checkers, but they are good only for checking output for all 6 power transistors (you can do that with universal meter also). They dont tell you anything about load conditions work of board.

DC inverter- dedicated power supply
AC inverter - VFD of sufficent power and voltage

Genarl practice is changing inverter board and compressor in pair, or outdoor unit complete.
Manufacturers goal is not to repair but to sell more.That is "only way" these days. Look whoo is most valuable company in the world. Apple, and they realy, realy, realy.... dont wont that you repair anything.

[RBM]

Thanks for your replys Nike,