I remember measuring about 350 V from somewhere to somewhere - but I don't remember where. The motor in question was intended primarily for window shades (which could be huge).

I used relays in my designs. Because switching is infrequent, a suitably rated relay will last for decades. The four-shade board used those vaguely cubic relays that are well under a dollar each. The two-shade (with common control) board, of which there are thousands in existence, used smaller 2-pole relays (pole per motor, these motors must not be connected directly in parallel).

This looks informative:
http://www.vishay.com/doc?84780

 

Which picture? currently I am not concerned about the leakage current, but about the high voltage (400V) coming back to the SSR from the motor.
Is there a way to protect the SSR from that voltage? the activation time of the motor in a specific direction is up to 45 seconds, which means the protection would need to be active in this time region.

Should it not be that when you turn off the motor, the energy stored in the coil gets returned to the relay, because there is nothing to discharge it to the source?

 

Can you please give the specs of the motor or a datasheet?

 

Can you please give the specs of the motor or a datasheet?

We went through that earlier, it is just a guess right now, mine was a AC PSC type.
Max.

 

Should it not be that when you turn off the motor, the energy stored in the coil gets returned to the relay, because there is nothing to discharge it to the source?

This is possible but probably depends on which type the motor is, and I cant know that. This is a small problem

Personally I would have used a higher current than 2a for a motor application, there is a OPTO22 version with practically the same foot print, that is rated for 4A at 380vac working voltage. MP380D4.

My $.02: I'd have used an SPDT relay for direction, the SSR for power, with a delay btw relay and SSR.
The relay isn't switching power and provides winding isolation (which sure looks necessary).
The delay could be a dual comparator: one side has an RC and a volt divider reference for time,
It's output feeds the other comparator with another volt divider, all fed from the move switch (through one of a pair of diodes).

Thanks for these suggestions! From these responses I understand I should redesign my board with new Relays/SSR's.
Just to be sure, there aren't any simple ways to protect the SSR's from the 400V coming back to them?

 

Is this a one-off? Or are you installing systems?
I would use the OPTO22 I mentioned and it should be OK IMO.
Max.

 

This is a one-off.
found this with 70% (!) off:
https://www.amazon.com/Opto-22-MP380D4-Control-Isolation/dp/B0058UYJBS
Do you find it reliable to buy this from amazon?

 

I have found Amazon to be very reliable as to suppliers and quality.
Max.