Jimmy P
Jun 1st, 01, 6:28 AM
I installed the big fan and am using a thermo-stat control and a 45 amp relay to power up the fan. I found an interesting side benefit of the 6,000 cfm fan. It makes the A/C work great!!!! I want the fan to come on with the A/C compressor. I assume I need another relay. How do I wire the second relay in?
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Triple Black 69 SS 396
http://albums.photopoint.com/j/ViewPhoto?u=1233564&a=9105086&p=37274567&f=0
garyB
Jun 1st, 01, 9:23 AM
Try this:
http://users.erols.com/brenegar/fan_wiring.jpg
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1967 Malibu
1967 Impala SS396 Conv.
"Excuse - no matter how valid - never alters or changes performance" - N Eldon Tanner
Jimmy P
Jun 1st, 01, 12:22 PM
I've done something similar to your drawing (thanks btw) and the temp switch b ack feeds the A/C compressor and turns it on when the temp goes high enough to turn on the fan. I don't like that. That means my compressor is on when I don't want it on. That's why I'm wondering if I need a relay between the compressor and the first relay.
Joel Koontz
Jun 1st, 01, 8:03 PM
A diode should be all you need to keep the current from back feeding.
Jimmy P
Jun 4th, 01, 12:09 PM
What does a diode do? Is it like a one-way check valve for current?
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Triple Black 69 SS 396
http://albums.photopoint.com/j/ViewPhoto?u=1233564&a=9105086&p=37274567&f=0
cjlandry
Jun 4th, 01, 12:25 PM
Yes, a diode is the electrical equivalent of a "check valve".
As an alternative, have your secondary relay's coil energized by the A/C compressor and switch the ground side of the fan with both relays. You won't "back-feed" through the ground side.
In other words, the power is connected directly to the fan's + terminal through a fuse at all times, but the ground is switched through the relays. The thermostatic switch controls one relay and the A/C compressor controls the other.
If you have any further questions about wiring it this way, shoot me an e-mail. I'll be able to get to it sometime on Wednesday.
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