I am not an electritian...can someone tell me how to wire my fan using this relay and a toggle switch? Thanks to all who take the time to help! P.S. reading left to right the numbers are 30,86,85,87,87a I think I wire it as follows but please correct me cuz I'm prolly wrong as usual....30,to battery,85 to ground,86 to one side of switch,87 to other side of switch,87a to fan. Is this correct,don't be bashful...
30 to (+) bat, 85 to ground, 86 to switched (+) (other side of switch goes to (+) source under dash) , 87 or 87a to (+) fan (looks like it can be used to power 2 accesories) of course other wire on fan to ground
I do not understand...I get the power in (30) ground(85) one side of switch to (86) wire to fan (87) where do I hook the other terminal coming from the toggle?Also,mine has another terminal on relay(87a) sorry for the dumb questions I am an Ironworker not a sparky....
Make sure you have a big enough relay for the fan. Some of the bigger fans need large relays. My cooling components recommend 75 amp.
I got this fan out of the junkyard and have no idea what it is out of. The reason I am installing relay (50 amp I think) is because I had it wired to a 50 amp Toggle with no relay and the switch started smoking...Now what?
Thanks for posting redlineracer - I am watching this with interest too as I am about to install a CCI fan controller and my electrical knowledge is a big el zippo....
Another illustration I "borrowed" from somewhere. On a 5 terminal relay with a 87A terminal the 87A is connected to terminal 30 when the relay is not energized (off) so it is not used in your situation.
That is exactly what a relay is intended to do...........allow the operation of a high draw accessory without having to run that load directly through the switch. By using a relay all the heavy work is done by it and the switch only has to supply a small amount of current to trigger the relay. Think of a relay as a heavy duty switch that instead of being flipped manually by your fingers is actually turned on and off by the current that flows via the secondary switch or power supply. Don
You should run the wire from the battery to the fan via the shortest practical path with the relay in line. Since it has a high amp draw make sure your main power wire and earth return are rated higher than what the draw is and a fuse on the power wire close to the battery that is higher than the fans load but less than the wires amp rating. Happy motoring. JW
I believe if you are over loading a switch rated for fifty amps, then you will overload a relay of fifty amps as well. I think you need a higher relay if this is the case.
I read all the electrical posts on the HAMB, and know less or get more confused with every read. Were do the numbers on the above mentioned relay come from, the 30/85/86/87......and sometimes 87a? Do they actually mean something? Bob
They mean something to Robert Bosch. The rest of us just follow the diagram. That same relay numbering has been used by Bosch for 40+ years...
Fortunately for myself, I've been around relays and relay logic for my entire career. They can be intimidating to understand at first. Below is a link to one of the best lessons I've ever seen posted as to understanding what relays are, and how they do what they do...GOOD read! DD http://www.bcae1.com/relays.htm
D D COOPMAN, that is a wonderful link with nice clear photos. Would I ever really need one of these somewere on a non electric fan car?
The 87 and 87a are like on a micro switch where you have normally open and normally closed switching . 87 is nomally open and 87a is normally closed when no signal is sent to 86. This gives two types of switching options, 30 is the max power in ie; 30 amps,86 is switching signal and 85 is ground for the relays coil to work. JW
37Kid...I'm not so sure about the turn signal set-ups, but certainly should be used for fans, fuel pumps, and I like them for headlight applications, so that the headlight SWITCH is not carrying the full current to operate the headlights. Protects the switch, and keeps lights bright...virtually no voltage DROP to bulbs through a weak switch. DD
So that would cut down the chance of a headlight switch/dashboard fire? If so I better read that link after all. Bob
I had a pair of switches that worked through a bank of 4 relays to operate turn signals/brake lights. I changed that to a specialty toggle switch when I re-wired, but it actually worked fine and with both switches on,you had 4 way flashers
Excellent thread and ***istance with this topic. Thanks to all who have participated. All the best, Dale Cleveland OH
upspirate...I apologize for sounding like I was "poo-pooing" your idea of using relays for turn signals. T-signals certainly CAN be made to work using relays, as you're aware. Just don't see it very often at all, and it takes dedicated, knowledgeable circuit design to implement. DD
The best way to stop electrical fires is to use wire that is rated higher than the load can be and have the correct rated fuses for the application as close to the power supply as possable and use switches that are correctly rated also. JW
37Kid...Not trying to scare you in the use of the normal headlight switch...gazillions of 'em have been used for years, without fire. Many, however, are "sized" safely-enough to carry the load, but in doing so, can hinder the FULL voltage eventually getting to the bulbs, as in voltage drop. That voltage drop will cause DC bulbs to glow more dimly than if getting the full 12v or so that the bulds are designed for, especially as some of these OLD switches age. Using relays, the headlight switch is used only to trigger the coils in the relays...not deliver the full current to the bulbs, as the relays do. DD
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