Compressor start protection?

Hi, I have a condenser unit from a split system AC I am using to cool water. I bought a temperature controller kit, and it worked, but I accidentally plugged it back in before the compressor had time to stabilize. Compressor didn't start, drew huge amounts of current, and sure enough, the triac exploded.

I am now trying to modify the circuit to use a relay instead, however, I'd like to ask, does anyone know how to make a little circuit that will prevent the compressor from starting up within say, 5 minutes of it shutting down? I know most window AC's have this feature, and I know you can buy modules to do it (They are expensive though).

My guess is they use some sort of capacitor to run a timer while the AC has no power, but the capacitor would have to be huge to keep relay contacts open for 5 or so minutes.

Cheers,
Dan

I had to replace a start capacitor on my outside unit, been about ten years now ($12.50, apposed to $75 to have someone come and look at it...). Fortunately, I noticed that the can was swollen, and that was the only problem. Never found out what caused the failure, always blamed the neighbor kids. The capacitor wasn't very large in value (around 10 uF, at 370 VAC), but was under the impression that the purpose was to give a little current boost at start up, so it doesn't stress the control circuits. I've had very few problems with my AC.

Instead of putting the timer on the compressor side, why not on the control side? Couldn't you just wait 5 minutes, before it sends the start signal?

HarveyH42 said:

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Instead of putting the timer on the compressor side, why not on the control side? Couldn't you just wait 5 minutes, before it sends the start signal?

Click to expand...

I agree...... Not sure what the required time would be but 5 minutes sounds safe.

It doesn't have a control side, I only have the condensor unit

I decided to do this with a microcontroller, and using a nice big 250VAC 30A relay.

Cheers,
Dan