electric fan - two live supplies?

R

Rorie

Active Member

Posts

641

• May 18, 2016

• #1

Re-wiring my electric fan as the existing wiring is too small and heats up.

At the fan, there are three connection pins which currently are 1) live feed direct from battery (via inline fuse), 2) live feed direct from battery (via in line fuse), 3) earth (back to battery).

I have tested both independently and both power the fan independently,.... so why do i have two live feeds? I must be missing something? Why would the fan have two input pins doing exactly the same thing?

Thanks

 

Flossie

Well-Known Member

Posts

11,418

Location

Shropshire

• May 18, 2016

• #2

One should go to a temperature sensor for automatic switching when the coolent reaches too hot. The other is a manual override just in case.

 

R

Rorie

Active Member

Posts

641

• May 18, 2016

• #3

Ah ok. So in the situation where i have a thermostat being the 'switch' on the relay (via a switch in the cab with override capability), i only need to utilise one of those live ports on the fan as the other is then redundant?

 

Flossie

Well-Known Member

Posts

11,418

Location

Shropshire

• May 18, 2016

• #4

Yes, is it maybe a 2 speed fan?

 

R

Rorie

Active Member

Posts

641

• May 18, 2016

• #5

The existing wiring had both connections 'live' at the same time. I assume that wouldnt make the fan faster? It would be one connection for 'low' and a different one for 'high'? When i tested each connection, i didn't notice a difference in speed (by sound)