I have recently dismantled my old washing machine to reuse some parts to make a tumbler. Being able to reuse the motor (230V AC) would be useful. I have an Invertek Optidrive E2 VFD that I use to drive a 3-phase motor on my lathe. Does anyone know if it would be possible to use it to control the speed on the washing machine motor or is the PWM option better?
If the latter, I'm guessing trying to reuse any of the circuit boards from the washing machine is likely to be difficult as they'd be integrated with all the other functions one wouldn't want or is there likely to be a separate motor controller board I could hack?
I don't think so. It's from a UK model Hoover domestic machine and doesn't have any label on it. The wires go to a speed controller (or something on the end of the shaft), two brushes and two coils.
Further research shows that I can scavenge a triac from the washing machine circuit board (which I have located). I'll also need a diac which I can't see on there but they're not terribly expensive to buy so shouldn't be too much of a problem to make a simple circuit. Arduino not required, it seems!
Its a universal motor if it has brushes. It will have at least a couple of field coils for crude speed
control.
Washing machines can have universal, 3-phase induction or brushless direct-drive motors, and
possibly some other sorts too.
For a universal motor you can in theory use a DC drive, but the motor will have been designed
so that the inductance of the field coil helps to limit the current, so its not straight forward to
figure out the best way to drive it on DC - you'd have to measure the AC currents in normal
use, measure the winding resistance and figure out a DC voltage that's suitable. The armature
will need mains-level of voltage to spin at max speed.
Well, despite your good advice above, I thought I'd go a different way!
I connected one brush and one coil together and put the other coil and brush to a 12V car battery. Motor spins up well. By connecting the other brush to the coil I can make it spin the other way around. Doesn't go too quickly and the project doesn't require a great amount of torque (and it will be driving the original reduction pulley anyway) so happy days!
I suppose I could tap into the two wires that go to the end cap to see if they're giving out some sort of pulse which I could read out on a display but I don't really need to know the speed that accurately.
You understand the risks of running an unloaded series-wound motor do you? Rotor explosion is
worst case (probably only see a winding escape/siezing, but still its a life-threatening scenario).
I've seen them running like that on YouTube but using mains. I'm using 12V and unloaded it spins up and runs at a decent speed but nowhere near enough to cause damage. Now it's loaded it's turning much more slowly and the tumbler barrel is doing about 45rpm. Might connect it to a 19V laptop supply later but no chance of it spinning out of control now - it struggles to turn the drum as it is
Here's the "finished" product - needs a bit of refining but as proof of concept I'm quite happy
