I made a remote (GSM) controlled module for a 3 phase pump close to my friends house. The pump should run at night, and walking the 1km to the switch while they are sleeping is the problem.
The manual switch, switches 3 phases which is put through a 4 wire cable (no ground) to the pump 50 meters away and 20 meters down from the manual switch. At the pump there is a fusebox and a small box which switches off the pump in case there is no water output detected (the water pressure box). The pump pulls a max of 16Amp, the actual amount I don't know (the fuse is 16amp)
My module switches the 3 phase power using a solid state relay ( Eurotherm RS3DA 30A ). I see that the GSM part works and switches the Solid State Relay on, but the pump does not start.
I am not sure what this causes, I had no way to measure the output, just having a voltage screwdriver to test there is voltage on the output of the relay. At some point the pump after some resetting of the water pressure box) did work but it would never by just powering the whole thing via the relay. Pulling out the 3phase connectors out of my module and connecting them directly will start the pump without a problem.
(there is some waiting involved after running the pump, you cannot just switch it on and off).
At home I could not realy test the relay except for the GSM module (based on Arduino)
I am not sure why this does not work. Could the solid state relay change the 3 phase in such a way that this happens because of power loss (less Voltage?) Next time I am there (it is a 12 hr drive) I can bring my voltage meter, but it does only do one phase. Any other things I should buy and take along to test en compare the module in the real world? Would it help to put the relay after the fusebox? Should I look for a mechanical relay for switching the 3 phases? Will that solve my problems, or is it just neater (there is a fuse at the switch uphill as well).
If necessary I could hook into the water pressure module but that costs something in the order of 800 USD (my module was about 120 all in) so if I break that I might loose a friend (and my right to visit their remote place).