I would like to control the motor of my washing machine using an Arduino. It's an old washing machine with a mechanical controller and an AC motor connected to a 12.5 uF run/start capacitor. According to the motor specs, it operates at 230V and draws 3A (probably not the peak value, but during operation).

My thoughts:

I would like to control it using a relay with the lowest budget possible. Since it's a large inductive load I want to avoid mechanical relays, especially the cheap ones available on Aliexpress due to arcing when the connection breaks. I'm afraid such a relay would quickly start malfunctioning.

I could use something like a contactor but they are not cheap.

The SSR-40D relays look good and can also be conveniently connected directly to an arduino GPIO, but they are zero-cross relays which are not suitable for controlling large inductive loads due to large current surges. Random triggered or peak-triggered SSR relays are pretty rare and expensive, so I'd like to avoid them. My thought was to use the zero-cross SSR, with the highest available current rating, like the SSD-100D (100 A) to control the motor.

I would just like to make sure I don't burn our house down with my DIY shenanigans. Namely, what is the peak current flowing through the high voltage side of the relay I should expect from switching on the aforementioned motor at the zero-crossing point for the given specs?

  • \$\begingroup\$ I'm thinking this might be an X-Y problem, what are you really trying to do? \$\endgroup\$ – Tyler Apr 13 at 14:19
  • \$\begingroup\$ Thanks, I was not aware of this concept. Learned something new. I edited the question. \$\endgroup\$ – Dave Apr 14 at 3:58
  • \$\begingroup\$ How about turning the mechanical input into digital input? \$\endgroup\$ – Unknown123 Apr 14 at 11:07

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