86, 87, 87a, 30, 85? Help i dont know relays!

[paxton350]

someone please explain to me like im a 5 year old how to use a relay. ive looked online and have only found schematics where they go way to far into depth. thanks,

-chris

[scotts94_z28]

pins 87 and 30 are the load side of the relay while pins 85 and 86 are the control side of the relay. now say you are wiring a fuel pump with a ground side switch pin 30 and 85 would go to the positive side of the battery, pin 87 to the positive side of the fuel pump, and pin 86 would go to the negative side of the fuel pump and battery with a switch between them.

[MN6WS6]

Let me try to get not real technical. 85 and 86 are basically what tells the relay to turn on or off. If 85 and 86 see both power and ground, then the switch turns on. If either one does not have power or ground, then the switch stays at rest. 85 can be power and 86 ground, or 86 can be power and 85 can be ground. It doesn't matter, as long as one has power and one has ground.

When the switch is off, 30 and 87a are connected. When the switch is on, 30 and 87 are connected. Most of these relays are rated at 30 amps. They do make smaller ones that are only rated at 15 amps. The normal relay is about a 1" cube (1"X1"X1").

[Rob B (shoebox)]

someone please explain to me like im a 5 year old ...

Son, go get your dad...

[Joe 1320]

someone please explain to me like im a 5 year old how to use a relay. ive looked online and have only found schematics where they go way to far into depth. thanks,

-chris

A relay is an electronic switch. Instead of using a finger to flip the switch on and off, a referance current is sent to the relay that turns on a small electromagnet. The electromagnet pulls the contacts together, making the current flow through the relay switch. When the referance current is removed, the contacts seperate and current is stopped.

How it is to be wired was explained already.

[paxton350]

ok this is what i got out of that scott, i drew a diagram, however im confused with the switch and the signal wire, the signal wire (coming from the ign tap on the fusepanel. wouldnt the switch be the +12v signal coming from the fusepanel? why would i run that to ground? also why is pin 87a empty? or it doesnt matter? thanks alot!
http://i4.photobucket.com/albums/y13...cpumprelay.bmp


-chris

[paxton350]

hmm ive been giving some deep deep thought to mn6 ws6's post . ok so your saying that my 12v ign source which basically tells the relay to turn on or off will connected to either 85 or 86, ok good got that. now would i just ground 85 or 86 to the frame, k got that. now for the real deep thinking now when the relay is on 87a is off its never used, k got that. 30 would be a hot lead going to my battery and 87 would go to the + side of the pump. wow i think i got it, this took some deep thought but im glad becuase now i understand relays i guess i can think of 87a as 87 (a)lways off! thanks guys!

p.s please disregaurd that last post

-chris

[MN6WS6]

You got it! I tried to make it as easy as possible for you to understand.