hippy wrote: ↑
Sat Aug 31, 2019 7:06 pm
How exactly is this 120V contractor coil running from 240V mains ?
Here's the diagram from my machine.
You get 240v from the difference between the 2x 120v coming in. I'll put my multi meter on it and confirm. In the diagram, a single wire is coming from #5 and feeds both switches and it then goes to both contactors which turn on both the high and low on the motor. You have to hold the button until #8 lights up.
I think I've read somewhere that it's Felder's way of running a 3 phase motor with single phase, using only 2 windings. The specs says 3kW motor which is about 4HP and it's pretty uncommon. Felder is from Austria and that was probably their clever way of adapting their machine for NA markets.
From my limited knowledge, North America motors have a centrifugal switch that does that for you.
#4 is the ON switch, #3 is the off switch. The diagram and what I see inside the machine doesn't show any breakers so I have to assume 20A on every wire.
I don't understand how the entire circuit works, just that if I put 3 relays instead of the 2 switches, the machine will start and stop. I think I might have answered my own question.
Felder has a remote starter for this machine but it's over $200 and I thought I could probably do the same with a spare Pi or arduino, $20 worth of Chinese boards from Aliexpress, curiosity and a willingness to learn.