Re: Turn ON delay relay

Vollrath, Don <dvollrath@...>

Dale, If you are contemplating switching 18Vac to a booster it doesn't need to meet all the UL/NEC agency requirements so you should be able to d-i-y. Find a suitable 10-20amp rated relay with a 12Vdc coil. (think automotive) Add a 1A, 100-200V bridge rectifier to the incoming 18Vac to power the coil. Determine relay coil resistance ohms. Calculate a series resistor value that will end up with ~12Vdc across the relay coil when starting from ~15Vdc. Then add a big value 25V rated electrolytic cap directly across the relay coil as a simple RC time delay to pick up the relay. Use the relay contacts to route delayed power to your time delayed apparatus. There are many more sophisticated ways to do it, but all require more design value considerations and parts. Purchasing anything UL rated for 115Vac operation means mucho $$.

-----Original Message-----
From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of dale_gloer
Sent: Thursday, January 26, 2012 9:29 AM
To: WiringForDCC@...
Subject: [WiringForDCC] Turn ON delay relay

I need a device that can delay the Turn On of a power supply for a second or so after power is applied to other related and connected components.

I have searched for a relay that would accomplish this but have not found anything suitable, either not the correct function or the cost is prohibitive.

Ideally the input to the device would be about 18 volts AC but other common voltages, like 12vdc or 120 vac, would be acceptable.

Does anyone have a recommendation?

Dale Gloer


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