I am working on a project that uses a Ulka water pump rated at about 0.5A. I will ultimately want to control the pump using an Arduino, however before I attempt that to start with I am just using a push button switch wired up as the schematic diagram shows:
From what I have read here, an inductive load (which I believe the Ulka pump to be) requires a random switching Solid State Relay (SSR).
So first I tried a random switching SSR rated for 5A, which didn't work, but I could hear the pump humming all the time.
Just in case, I then tried using a zero-crossing SSR rated for 10A to switch the active (hot) wire, which worked, except the pump hummed when not in use. This made me think maybe I need to switch both active (hot) and neutral wires, but I thought that since its a single phase switching just the active (hot) would be sufficient.
Should I be switching both wires?
I also tried using an electromechanical relay rated for 15A, I heard the relay switch, but the pump did not turn on.
Could I potentially use a zero-crossong triac driver to accomplish this?
Best Answer
I finally found the cause.
The hum was coming from the 3 way valve, which is also activated when the brew switch is flipped. When I activated the hot wire of the pump and the hot wire of the 3 way valve using a relay, the pump worked as it should.