OK Alan,
Lets see if I got this. Its not the relays, its the wiring connections at
the relays that cause the problem. So by having two relays you reduce the
load on one connection by 50%, thus making the connection's work less. OK
now what about the wire from the motor you have to make a connection there
from two wires to one, wont that connection over heat eventually?
Mike 50 3100
> Hey, Mike.
>
> In a way, you nailed it ... but not exactly.
>
> Here's the full scoop on it from MadElectrical.com:
>
> The reason for our recommendation is to prevent slow-meltdown of the
> wire harness connector at the base of the relay. Electric motors are
> prone to overheating connections and switches in power delivery
> circuits.
>
> Two Relays can handle most fan systems. However, with only one relay
> pulling the entire load for powerful radiator fans, the terminals
> will often overheat if the fan system is used for long periods of
> operation.
>
> Meltdowns often occur with the Male/Female-Flat Blade terminals in
> continuous duty/high current demand automotive systems - especially
> with power loads to electric motors.
>
> The current load limitation that these relays can handle is with the
> wire connection design that will join the wires to the relay, rather
> than the contacts inside of the relay being the weakest part --
> which is why it will do no good to compare the current rating
> published on the relay to the RMS current draw rating of a radiator
> fan motor.
>
> Alan
> http://www.AlanHorvath.com
> Acoustic Rock ... for real.
>
>
>> OK Alan I will bite. Why the two relays? Is this incase one quits?
>> Mike 50 3100
>>
>>> If you do go this route, I suggest *no* circuit breaker ... *no*
>>> fuse on the fan ... but, rather, use a fusible link. See this:
>>> http://alanhorvath.com/54chevy/fusible_links.php
>>> Also, I put *double* relays, too - see this:
>>> http://alanhorvath.com/54chevy/mad_electrical_2.php
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