I have a ssr relay to control ac230v. From esp32 it is 0 v when off.
Ssr is only controlling 1 of the 230v ac cables, 1 fase.
It is brumming like 50 hz.
Any idea how to solve?
Any idea? Not without the documentation on the SSR and the AC current it is controlling.
Shure, ill update post in a few sec.
Defective or counterfeit SSR.
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I remember reading a post a long time ago that 3volt (ESP pin) was not enough to drive those (mostly counterfeit) SSR.
Power the SSR input from the 5volt/V-in/USB pin of the ESP, and use a small NPN transistor with 1k base resistor to drive it.
Leo..
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The relay is humming? Or the motor?
As an experiment, just connect the relay input to 5V and ground and see if it turns-on.
And if you're not sure about the wiring, temporarily replace the relay with an SPST switch. (A regular light switch will work if you have one.) Or, you can simply bypass the high-voltage side of the relay and connect the two wires directly together.
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Only motor, did disconnect to test.
For info, system is grounded
Thanks for advice, Ill try, but motor is humming when 3.3 is physical disconnected.
It can be, but I have used many of same relays, they seems to work pretty good.
Motor, relay is silent to my ears
This I have not tried, but it turns on with 3.3v, so I expect it to turn on with 5v
Then the motor starts and sound is higher than the mumming when turned off.
The SSR, when it's off, still has a snubber network connected.
10n + 47ohm when you look at the youtube teardown videos of this SSR.
That could be the source of your noise.
Leo..
Hi,
Your motor;
Looks like a 2 phase motor, it produces the second phase with that brown capacitor, it phase shifts the current.
SO the total current through the SSR NEVER gets to zero, so the SSR triac will not turn OFF.
Hence the brumming.
Can you post a diagram of the connections on that motor terminal strip, include the wire colours.
Thanks.. Tom.. 
Thanks
This is probably the solution.
I messured 0.6 mA 230V, enogh to make 50hz buzz
A 2 phase motor working on a single phase with a capacitor to produce the out of phase current.
In the upper diagram,
W1 is fed directly with mains current.
W2 is fed current 90deg out of phase to W1 because of the capacitor.
This makes the field in the motor rotate in one direction.
In the lower diagram,
W2 is fed directly with mains current.
W1 is fed current 90deg out of phase to W2 because of the capacitor.
This makes the field in the motor rotate in the other direction.
Hope that explains it.
Tom..
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@TomGeorge
Perfect explanation, I though the cap was for noise
Learned something today!
Perfectly explained.
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Or a 1 phase motor with a few windings as 'second' phase to make it turn the same direction every time you start it. For a full second phase the capacitor would probably have been larger...
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