Need some more info on this, 3-phase or single?
Voltage and system (wye vs delta) would be more of an issue than freq'. Most motors will survive a differance in Hz with no problems. Many are dual rated. The refridgerant also does not know the differance, plumbing wise, it will act the same.... If using 3 phase motors they could be re-connected to compensate for voltage, etc. Some motors will fail to start, or have reduced power with the wrong source. (wye vs delta)
If you dont mind... when you say "split type air conditioners", do you mean seperate compressor and evaporator? If so, more often than not it is a leak in the coolant system. Do the units have refridgerant indicators? (Little glass bubble with a green - full - dot, or yellow - empty - dot in the middle) Reffer compressor motors also burn up when they are empty. The refridgerant acts as a lubricant and without it, it over-works the motor.
