Relays?

[mtnman210]

So I've looked a a bunch of different diagrams from different sites and cant' figure out which is the correct way to wire a rely. This is the curretn configuration I'm running right now on all my fans,lights,etc.. I found it on here.

For example I'll use my radiator fan. just for information I'm not running a temperature switch I have control of of the fan off a switch on the dash.

I'm using Hella's 30amp relays to windstar fans.

85: to ground block
86 through 30amp fuse into switch that has constant 12volt
87: to + side battery post
30: to fan motor

Now I have no idea if this is how it should be but the fans work and don't blow fuses. I'm just curious since I've seen suggestions on wiring relays many different ways.

 

[Russell]

85 and 86 power the coil in the relay, which draws just miliamps. You shouldn't need more than a 3amp fuse for the coil circuit.

30 is typically the post that is hooked up to your battery through a circuit breaker, fuse, or fusible link (depending on what you are powering through the relay).

For something like lights that does not have an initial spike in current, fuses work great. However, a device like an electric fan can draw a massive amount of current when it first starts up, and will often blow a fast burn fuse like an ATO, miniATO or maxi fuse. In that case, you want to use a fusible link that will take a few moments of high current before it burns. If you have something like a power window motor or electric trailer brakes that can easily overload the circuit on a regular basis (stalled out power window motor due to hitting stops, blockage on the track etc) it is handy to have a circuit breaker which will automatically reset itself after it cools down, and continue to cycle on and off until the overload condition no longer exists.

87 is the normally open post, meaning that when the relay's coil is not energized, 30 is NOT connected to 87, and IS connected when the coil is energized.

87a is the normally closed post, meaning that when the relay's coil is not energized, 30 IS connected to post 87a, and is NOT connected when the coil is energized.

 

[oakknight]

I got my crayons out .. I know its crude , but this is what i think it should look like .

 

[BILTIT]

www.bcae1.com

Scroll down on the right hand side to #36 Relays.

 

[mtnman210]

ok so I have them ass backwards. I wonder why they are working them

so my new setup is:

85: to ground
86: to a switch that is getting constant 12volts and is fused
87: to + side terminal on fan motor
30: through 15amp fuse to + battery post

Does this look right to everybody now?

 

[BILTIT]

Looks good, 85 and 86 can have polarity either way, its just a big wire.

 

[Russell]

Looks good! It would have worked the way you had as all the relay does is open or close contacts internally. The relay does not really care which way current flows. Now everything is fused properly though, that was worth fixing