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someone check if this is correct?

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121458
Printed Date: May 29, 2024 at 12:55 AM


Topic: someone check if this is correct?

Posted By: 2001eclipse
Subject: someone check if this is correct?
Date Posted: April 22, 2010 at 6:30 AM

Im trying to see if the top portion of the pic is the same as the bottom portion?

posted_image



Replies:

Posted By: i am an idiot
Date Posted: April 22, 2010 at 6:49 AM
On the left relay, the wire that goes to the right relay is connected to the wrong terminal.  It should be connected to the top terminal of the left relay.




Posted By: oldspark
Date Posted: April 22, 2010 at 9:19 AM
You Idiot!
As usual, you are correct. The left 87a should be to 87 instead.


And not that I care nor that it effects me (because I NEVER use internally protected relays), but TRIVIALLY the convention is ground (more negative) to #85 and the more +ve (IGN & H'L on) to #86.
But like I said, it is trivial and does NOT effect you because a coil is a coil and is non polar - hence why that IDIOT didn't mention it...

But in case you happen to have relays that have an internal spike quenching diode, or happen to be a certain pedantic point-scoring richard-head from a previous life...
(Any internal quenching diode should be clearly shown on the relay case/schematic. Quenching resistors do not matter.)

And if you do - and connect them wrong and hence blow a fuse - I recommend my method: Replace the fuse with a nail or other hi-current short circuit; blow the crap out of the diode. Then - if YOU need a quenching diode - fit a diode externally to the relay's wiring so that YOU determine its polarity; use normal relays; and can inspect/replace said diode etc.




Posted By: 2001eclipse
Date Posted: April 22, 2010 at 12:36 PM
Got it. So 87a from the left relay is not used, and 87 from the right relay is not used.

Not sure if it matters, but this relay setup is intended to turn the foglights into DRL's on a 2003 Murano.




Posted By: oldspark
Date Posted: April 22, 2010 at 1:11 PM
I think I'd omit the RHS NC relay...

Hence LHS 87 to the Fog Lamp/s.
Connect HL on to (LHS) 86 instead of 86 to GND. (If HL is lamp power and not to another relay's solenoid/coil).

So with both IGN & HL off or on, the relay & Fog is off.
If IGN is ON and HL off, the HLs ground #86 hence energising the relay and Fogs on.
The same can occur with IGN off & HLs on if that is possible, but a series blocking diode can prevent that - eg, a 20c 1N4004 etc in the IGN or HL line where the Kathode (lined) end is towards the HL source (away from IGN). Hence current can only flow from +IGN to grounded/off HLs, but not from +HLs to GND'd IGN.

Simple eh?




Posted By: 2001eclipse
Date Posted: April 22, 2010 at 1:48 PM
I think Im even more confused now :P Ive re-read your replies numerous times, and I think Im going to give the hamster in my head a break and try to focus on this again later!

Anyways, much thanks for the... informative information :)




Posted By: oldspark
Date Posted: April 22, 2010 at 6:05 PM
Provided "HL on" is to a load that is much lower impedance than the relay coil - eg, a "bigger" relay coil, or the fog-light bulbs.
(Otherwise the coil will not get current to actuate reliably - its #85 terminal forms a voltage divider with whatever unpowered load connects to it.)

posted_image





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