relay question

Submitted: Tuesday, Apr 07, 2009 at 18:47
ThreadID: 67653 Views:1705 Replies:7 FollowUps:1
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hi all , can you get 12 volt relays that are - normaly open and normaly closed (2 seperate relays) . the next question is can you get one relay that will do both ? cheers
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Reply By: Member - Paul C (WA) - Tuesday, Apr 07, 2009 at 19:00

Tuesday, Apr 07, 2009 at 19:00
Short answer is Yes x 2
AnswerID: 358638

Reply By: Member - Fred B (NT) - Tuesday, Apr 07, 2009 at 19:11

Tuesday, Apr 07, 2009 at 19:11
Most relays come with a common +ve terminal and the moving contact arm moves between the NO and the NC position; so you can use the relay to hold the circuit open or closed. Dual relays are also available eg control 2 circuits.
Fred B
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AnswerID: 358645

Reply By: JR - Tuesday, Apr 07, 2009 at 19:24

Tuesday, Apr 07, 2009 at 19:24
You need a "change over" relay
yes you can get them, bit hard to find on the shelf though
Someone had a link to Traxide I think which had them there
JR
AnswerID: 358647

Reply By: Member - Paul W- Esq (VIC) - Tuesday, Apr 07, 2009 at 19:44

Tuesday, Apr 07, 2009 at 19:44
if all else fails go to a place that installs car alarms, they use these relays in ignition cut outs.
AnswerID: 358654

Reply By: ABR - SIDEWINDER - Tuesday, Apr 07, 2009 at 20:50

Tuesday, Apr 07, 2009 at 20:50
We use 5 pin 30A relays.

Does this drawing help ?



Regards

Derek from ABR
AnswerID: 358673

Reply By: Geoff (Newcastle, NSW) - Tuesday, Apr 07, 2009 at 21:01

Tuesday, Apr 07, 2009 at 21:01
zacc,
If you can get access to a Hella distributor one of the following will do the job,

3057
3057BL
3080

(These will follow Derek's diagram above)

Have a look and ask some questions and you should be set.

Geoff

Geoff,
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AnswerID: 358677

Reply By: zacc - Tuesday, Apr 07, 2009 at 21:37

Tuesday, Apr 07, 2009 at 21:37
thanks for all the replys . i think i will have to go with 2 relays .
what i actualy need it for is a landing light. during the day the batterie is charged by a small solar panel this is where the nc relay will go inline withe positve coming from the paneland the postive on the batterie. now when the light is needed to be switched on the power needs to cut from the panel to the batterie other wise the globe will get some 18volts ( that is what the little panel puts out). this is where the n.o relaylay will come in , it will take power from the batterie to the globe while turning the other relay on thus opening its curcuit . this semms to be complecated but i think it would be more reliable than what is there now . it currently runs a little curcuit board and they keep dying because on the heat sitting in a paddock . reays are designed to be abused a bit and can with stand heat .
AnswerID: 358690

Follow Up By: Ianw - Tuesday, Apr 07, 2009 at 21:51

Tuesday, Apr 07, 2009 at 21:51
not so, zacc

If a small solar panel is connected to a 12 volt battery, the voltage will not go above 12 to 14 volts. The panel only puts out 18v with no load attached. As soon as a load (light) is on, the voltage will not be above around 12.6 volts so your light will not be damaged. Anyhow ,if your light is only required at night then the solar panel is not charging, so voltage will be 12.6v. You seem to be making a simple job very complicated !!!

Ian
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FollowupID: 626738

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