[TR] Electric Fan Relay

[DAVID MASSEY]

 One moment, please, it is the cathode end that has the stripe.  Connect that to the positive terminal.

Connecting a diode across the coil will do noting for the contacts burning up.  It will protect the temp switch, however.  Placing the diode across the contacts will quench the arc there.  

Another possibility, one that I use regularly, a varistor designed for just such an application.  Something like this:
https://www.digikey.com/en/products/detail/bourns-inc/MOV-10D220KTR/2407603
This part is not polarity sensitive and will limit the voltage across the contacts to a point where no spark will be generated.

 
Dave 


 
 
-----Original Message-----
From: ronald.olds at mchsi.com
To: keithstewart at bell.net
Cc: triumphs at autox.team.net
Sent: Thu, Jun 16, 2022 12:02 pm
Subject: Re: [TR] Electric Fan Relay

Keith,

I would recommend connecting a 1N4004 diode across the positive an the ground terminals of the relay coil. Connect the cathode end of the diode to the positive terminal and the anode end (the end of the diode with the line om it) to the negative terminal. this will have no effect when the relay is energized.  When a relay is denergized it generates a spark which can burn the points. The diode will allow this spark to travel through the diode and  dissipate.
                                                                                                                Connect to relay negative connection.                            Connect to the relay positive terminal.

Diodes should be across the terminals of all relays and solenoids.

Ronald Olds

From: keithstewart at bell.net
To: triumphs at autox.team.net
Sent: Thursday, June 16, 2022 11:38:04 AM
Subject: [TR] Electric Fan Relay

I have a 62 TR4 with Trim Line electric fan, Derale fan controller, 30 amp fuse, and 30 amp NAPA relay. In the past 5 or 6 years, I have likely replaced the relay six or seven times. The wiring seems pretty straight forward and all seems in order. I really have no idea where to look next. Any suggestions? 

 

Keith Stewart 

keithstewart at bell.net 


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