Heavy Duty Relay for Air Compressor

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Old 02-29-16, 08:58 AM
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Heavy Duty Relay for Air Compressor

I have an old Allegro motorhome with an aftermarket air suspension installed in the rear (Jet Ride - no longer in production). When I first got the rig, the air compressor was shot. I installed a compressor from airbagit.com and upgraded the wiring with 4-gauge wire and a circuit breaker. I installed a 30-amp relay that activates the pump when the pressure drops below 100 PSI. I'm on my 3rd relay and it has failed in the same manner as the other 2: if the pump runs for a while it seems as if the contacts will stick closed and it won't shut the pump off! I assume the relay is getting too hot. I have to watch the pressure gauge and manually kill the power via the circuit breaker. Once it cools it's okay again. I got distracted the other day and pressure went up to 250 PSI. I need to fix this somehow.

I'm assuming the cheap auto-parts store relays are to blame. Can anyone recommend a heavy duty relay or other setup?
 
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Old 02-29-16, 09:29 AM
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Here are several that will work.

Solenoids

On/Off Single Contactors 12 Volt Coils

(I have no connection with Cloud Electric other than as a satisfied customer.)
 
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Old 02-29-16, 10:55 AM
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It's not the fault of the relay you are using. You're using intermittent duty starting relays. You need to use continuous type relays.

Furd left you a link above. I was involved in automotive electronics for years and I've always used Cole Hersee relays and contactors.

Solenoids & Relays | Steel & Phenolic Body Solenoids | Cole Hersee
Amazon/Cole-Hersee-24059-BP-Insulated-Continuous/dp/B0064MX7US
 
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Old 02-29-16, 01:52 PM
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Thanks both for the replies. I'll definitely be swapping my relay out for one of those solenoids.
 
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Old 05-18-16, 06:57 AM
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I finally got around to installing one of the suggested continuous relays over the weekend. FINALLY the system works correct. No more panicked shutting off of circuit breaker or yanking the relay when the pressure gets dangerously high. The old, intermittent duty relay would oscillate as the set pressure was reached causing the pump to start and stop rapidly. Then the pump would run every second or so until the breaker tripped. This new relay turns on and off with a solid click and stays off until it's needed again. Much better!
 
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Old 05-18-16, 07:47 AM
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I'm glad we could help you and thank you for letting us know the outcome.
 
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