I am facing a very strange (interference) case that has kept me busy for three days trying all I can think of with no use,
My problem in short:
I have two circuits as shown (1/2), when I operate circuit 2 with a switch coming out of the PSU to activate the 3 relays, they work fine and my circuit is OK and I get my LED lights on. HOWEVER, circuit 1 which is about 50-100cm away is affected (!). Two monitors connected to two of the PCs in circuit 1 "wobble" when the relays of circuit 2 are powered! Further more, I have some USB devices connected to each PC thru powered hubs and only the USBs connected to PC2 disconnect and connect upon powering the relays of circuit 2! To add to the mystery (I think it is), If I disconnect the 220V side on the relays and just power the relays, the monitors do not wobble but the USBs still get disconnected and connected. Last but not least, the monitors wobble when I power the relays but the USBs connect/disconnect when I turn off relays!
I cannot find any logical explanation to this!
I tried to distance the R1-R3 relays to as far as 150cm from the other circuit! I tried to wrap the 3 relays with foil paper to prevent or reduce the magnetic field (if any), BUT no use!
If I operate one relay at a time, the monitors wobble much less and the USBs do not disconnect. Two or three relays then I get larger wobble on the monitors and USBs connecting/disconnecting.
Anyone has an idea what could be the case?
I will try to supply the two circuits with a different phase each (I have 3-phase power).
I would really appreciate your help.