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I made a circuit using relays to control when to start some motors. Since there were four motors that should be connected, I made four identical circuits.

Testing each individually, they worked. But when you call everyone together, there is a big problem. One of the relays continuously switches the contacts very fast, without me giving any commands. It starts, vibrates for 4s, stops, waits 15 seconds and does it again.

I'm feeding them all with a source made by me that puts out 5v and 12v. I know that it feeds correctly because it is feeding other circuits besides these. Does anyone know what the problem might be?

Circuit below:

Circuit

The power supply im using is shown below:

Power supply

I'm using a 30V 5A transformer.

All circuits together:

Circuits

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$ – Dave Tweed Jun 22 '18 at 15:49
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If I understood your question correctly, you mean that when apply a 5 VDC to the coils of the relay it switches too many time for 4 secs and turn back off. I have encountered the same problem with an over voltage protection circuit, when voltage measured reaches the shutdown predetermined value it oscillates a lot of times for a period of time. I overcome this problem by connecting the input pin of the relay with a capacitor to the ground. it helped by charging the coil with a sufficient voltage for operation. make sure that you choose a capacitor value in the range of 100uF. try this out and tell us how it works.

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$ – Dave Tweed Jun 22 '18 at 15:50

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