| Author | Message | ||
     Henrik |
I'm installing a relay in the wiring for aux power. Here's a picture of the relay:  As far as I can figure the "85" and "86" connectors are for the main power = the feed that is being switched on and off by the relay. "30" and "87a" and "87" would then be the power that switches the relay. Is that correct? If so, can I choose either of the "87" or do I have to do something special? ... or have I got it backwards? Henrik | ||
| Bomber |
H -- I THINK ya got it backwards -- 85/86 is where the 12VDC connects -- when present, it'll pull the replay from 87a to 87, creating a curent path from 87 to 30, and breaking the path from 87a to 30 however, 2 minutes with a multimeter and a battery will clear up any confusion -- ya can't hurt it as long as you stick to 12vdc | ||
| Henrik |
Thanks Bomber; yes, a quick test is the way to go. Which fortunately reminds me I need to pack my multimeter for the trip .. thanks again  Henrik | ||
| Bomber |
don't repeat my mistake of bringing the meter, elec tape, and the film canister of majik smoke, but ferget to bring a foot or three of wahr -- I've managed to successfully diagnose problems without having the stuff to perform a simple fix more often than I care to remember -- oddly, you can ALMOST always find a bit of wire on teh side of any interstate ;-} | ||
| Henrik |
Bailing wire, wire fence - lots of options for quick and dirty electrical repairs. That's why I usually remember to bring regular old fashioned wire nuts - as well as some wire Henrik | ||
| Court |
87 is the N.O. (normal open)  | ||
| Jackbequick |
Bomber has it right. "85" is for 12V+ in from your ignition switch and and "86" goes to a good ground. When 12V+ flows through 85 and 86 the relay changes states. "30" is your 12V+ high amperage source (like directly from your battery). The 12V+ source would come out of the relay on either 87 or 87a, depending on whether the relay had power or not. The relay can be used as either Normally Open (87) or Normally Closed (87a). Taking the 12V+ "load" run off of "87a" would give you a normally closed (NC) relay. Power would flow from the battery to 30, to 87a, and to the load until 12V+ was applied across 85 and 86 to open those contacts. That is no what you want (I think). Taking the 12V+ load off of "87" gives you a Normally Open (NO) relay. The 12V+ is always present on "30" but does not appear on "87" until you have the ignition on. Turning the ignition on flops the relay from 87a to 87 and your load goes hot. I think this is what you want. The relay only gets connections for the switched 12V+ that controls the relay (that goes to a ground) and the 12V+ source which goes to your load. You can check and verify the NO and NC contact states with a meter. With no power, 30-87a should be a short and 30-87 should be open. Relays sort of make my head hurt because there are all those wires and connectors and when it comes right down to it, it is really only turning the 12V+ to the load on and off. Jack | ||
| Henrik |
Thanks guys - I'm getting the picture ... finally Jack - you're correct, 12+ load off "87" for NO is what I want. Now I just need to go home and actually wire it up ... Thanks again Henrik | ||
| Bomber |
H -- ya gots the skull work done -- that's the hard part | ||
| Road_thing |
I thought "wire nuts" was an STD. rt |
