Inverters and washing machine motors

[laurence6202]

I would like to know whether I can run a 1/[FONT=Helvetica, Arial,
sans-serif]2[/FONT]hp (~380W) washing machine motor on a [FONT=Helvetica, Arial, sans-serif]600W (1200W peak power) pure sine wave inverter.

[FONT=Helvetica, Arial, sans-serif]I had [/FONT][/FONT][SIZE=+1][FONT=Helvetica, Arial, sans-serif][FONT=Helvetica, Arial, sans-serif][FONT=Helvetica,
Arial, sans-serif][SIZE=+1][FONT=Helvetica,
Arial, sans-serif][FONT=Helvetica, Arial,
sans-serif][FONT=Helvetica, Arial, sans-serif][FONT=Helvetica, Arial, sans-serif](famous last words) [/FONT][/FONT][/FONT][/FONT][/SIZE]a [FONT=Helvetica, Arial, sans-serif]600W modified sine wave inverter which worked well off a car battery feeding into a UPS to run my computer during power outages. In a moment of misguided brilliance I thought I could use the inverter to power a Bosch 800W drill[FONT=Helvetica,
Arial, sans-serif], but a sign of smoke and a whiff of a burnt smell convinced me that the idea did not work. Now I would have thought there would be fuses to prevent such a calamity. Anyway,I opened the inverter, found the two power transistors that popped and replaced them (there was enough left so I could identify the[FONT=Helvetica, Arial, sans-serif]m)[/FONT], but without success so [FONT=Helvetica, Arial,
sans-serif]I[/FONT] gave up and bought another inverter - this time a pure sine wave inverter (at double the cost) as an upgrade to make up for my folly.

[FONT=Helvetica, Arial, sans-serif]Now I have another project in which I want to run a 1/[FONT=Helvetica, Arial, sans-serif]2[/FONT] hp washing machine motor to operate a home made winch to get muck out of a deep trench. My winch involves a [FONT=Helvetica, Arial, sans-serif][FONT=Helvetica, Arial, sans-serif]primitive[/FONT] clutch (slacking the fan belt) so the motor does not have to start on full powe[FONT=Helvetica,
Arial, sans-serif]r.[/FONT][/FONT]

[FONT=Helvetica, Arial, sans-serif]Question: Should I risk testing the inverter or should I play safe and hire/borrow/steal a generator instead[FONT=Helvetica, Arial, sans-serif]? I do have a clamp meter to check currents, but that does not help if I fry the inverter on start-up.[/FONT][/FONT]
[/FONT][/FONT][/FONT][/FONT][/FONT][/FONT][/SIZE] --
Regards Laurence
Cell 0827663807
www.gromitconsulting.co.za

 

[Marvo]

I guess the question is will the 1200 watts available peak power be sufficient to accommodate the start current of a 750 watt motor. My suspicion is it's going to either trip or be damaged unless it's a high end inverter like a Victron. For single phase motors we would usually work on around 5 x the run current being required for starting.

**edit**

Welcome to the forum by the way .

 

[Charlie_]

Do you have the washing machine that the motor came out of?
If so I suggest removing the wiring harness for the motor along with the speed control module.

 

[Lucien Nunes]

In theory a sine-wave output inverter should be able to power any kind of load without damaging it. This is not true of 'modified sine' which is not a sine wave at all (It's a 3-level waveform that just has the same ratio of peak to average voltage as a sine, so that both rectified loads like the computer PSU and resistive loads like lamps will operate normally). This waveform will not work correctly with phase-angle controlled loads such as variable speed drills, and that might be what killed the inverter as the drill would not have been using 800W off-load. As you saw, power semiconductors in inverters are under great stress and fail regularly, often at the slightest provocation.

Whether your new inverter will run your motor depends mainly on the type of motor. If it is a universal (brush) type with a phase angle controller, then provided the waveform is good it may be OK, also if it is electronically commutated (e.g. the modern direct drive type). A traditional induction motor might be more of a challenge as the starting torque / power factor / starting current are relatively poor.

Ensure you take suitable precautions (which I am not about to describe) to make the winch safe to operate, with regard to emergency stop / overrun brake / etc etc.