Jump to content
  • Welcome to 205GTIDrivers.com!

    Hello dear visitor! Feel free to browse but we invite you to register completely free of charge in order to enjoy the full functionality of the website.

Sign in to follow this  
Richie-Van-GTi

Normally closed earthing relay circuit.

Recommended Posts

Richie-Van-GTi

Putting this here as it seemed the most appropriate place.

 

I need to trigger an earth on a multifunction relay to control fuel pump and coil on my car, but i want it to shut off if the engine stalls etc.

 

Is it possible to run the earth through a normally closed relay to the battery earth, then on the coil side run a switch live across to the excitor wire on the alternator.

 

Thinking when the alternator stops the coil will trigger opening the relay to kill the earth on the fuel pump. On the fuel pump relay its a switched live anyway so it will die on ignition off so wont need juice when the ignition is off to hold the relay open.

 

Worry is that it wont spin up fast enough to break the earth side of the alternator when cranking?

Edited by Richie-Van-GTi

Share this post


Link to post
Share on other sites
Ryan

I don't think the alternator spins fast enough during cranking. It can be borderline at idle speed.

Share this post


Link to post
Share on other sites
Thijs_Rallye

You are basically describing the function of the tachymetric relay, with the only exception that the tach relay switches the live to the pump instead of the ground. Why not use that :)?

 

 

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×