| Author |
Message |
    
R. B. Bailey (Rover50987)
| | Posted on Monday, October 07, 2002 - 12:12 pm: | 
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Before I owned my IIa I never did anything on any of my cars but change the oil. I started reading and working and found that most mechanical stuff, other than main engine components and transmission stuff is pretty easy to work on on both modern and old Rovers.
BUT I DON'T THINK I WILL EVER FULLY UNDERSTAND MOST ELECTIRCAL STUFF - just seems mystical to me or something - especially when the TV reception is affected from a block away when my IIa is running!
My question: If I install a relay with the work light, (like in most of the diagrams I see on this web site.) does that mean I am essentially allowing the light to work when the key is turned - just like the normal light switches in the car? So the switch for the light will turn the light on and off, but only when the key is in the ignition - right?
If that is the case, is it possible, or even advisable, to put the circut in without a relay so that I could run the light off the battery independent of the rest of the car's systems?
http://landrover.mrbaileyshistory.net |
ken
| | Posted on Monday, October 07, 2002 - 01:53 pm: |
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You can run the circuit any way you want. The relay is only there to handle higer amperage then a switch. for instance if you had a work light and a battery and you just took the leads from the work light and hooked them straight up to the battery the light would come one but the only way to turn it off would be to disconnect one of the leads. now if you were to interupted one of the wires with a switch you could just turn it on or off; but the amperage is to high for a switch and would burn it out so you need to use a relay. A relay is a high amperage switch. You can run a switch off the battery that runs a relay so your lights run independant of you cars system. They also make high amperage switches but the tend to be big bulky and ugly.
ken |
R. B. Bailey (Rover50987)
| | Posted on Monday, October 07, 2002 - 02:41 pm: |
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OK, I think I understand. A relay is a switch, but it is "imbedded" in the circut. Is it sort of like a master switch for an individual circut? It can handle the extra amps, but it also controls the power from the main source? Or am I way off? Anyway, more explaination of what it is used for would be appreciated. Thanks |
ken
| | Posted on Monday, October 07, 2002 - 03:12 pm: |
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this is a relay http://www.partsexpress.com//pe/showdetl.cfm?&User_ID=8720200&St=3044&St2=88697540&St3=72244969&DS_ID=3&Product_ID=9683&DID=7
and this is how it works: http://www.1728.com/project3.htm
SPDT stands for "sigle pole double throw" that is the kind of relay in the first link and is the same one in the second link hope this helps.
Ken |
edward petrush (Exp3)
| | Posted on Monday, October 07, 2002 - 03:17 pm: |
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you are close.. the relays were designed basically so you didn't have 20 (or however many switches your particular truck has)- 8 guage wires running into the cab of your truck. Insead, they use a smaller (less amps) 18 guage wire to the switch (less expensive too) ... switches in cab can be smaller. Also with a relay.. (since it needs an energizing wire) you can safely wire the circut into the accessory circut.... if you just ran a power line from battery to high amp switch to accessory.. you could have a potential for battery drain... (from failed swich, forgetting to switch it off... etc..) |
R. B. Bailey (Rover50987)
| | Posted on Monday, October 07, 2002 - 03:39 pm: |
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Thanks, I think I do actually understand it now. But I will have to do it now to really figure it out. Once I see the wires connected and "see" it work, I will probably get it.
So when the on/off switch is thrown, you are actually turning on the relay, which then allows the circut to be complete to the light. Right? |
ken
| | Posted on Monday, October 07, 2002 - 03:40 pm: |
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YUP |
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