Rad fan ampage

9th March 2017, 14:18

Hi all

Been a while since I've updated my progress thread -
long story short all my wiring was butchered when I bought it.

Fan motor itself is operational but does not cut in.

Gone around it and wired in a switch to the dashboard to run it as and when required.

The only thing I'm not sure of is what ampage the fan should be getting - being a VTS it has the resistor as standard.
I think I've bypassed this however as I've gone: battery-fuse-switch-fuse-radiator.

It's got a 20a fuse at the moment which I think is amazingly high for a fan motor, and when switched on it looks as if it's spinning too fast and whirs slightly. Only used a 20a fuse as had a fuse handy but this is the max rating of the wire I used.

I don't think the motor will last long at this ampage and poses a potential fire risk!!!

Suggested/standard fan ampage please? I.e - can I use a smaller fuse or should I fit a resistor in line?

10th March 2017, 15:24

If this is a rad cooling fan --then 20amp is not much -look at thickness of wires on fan
30amp fuse not un common and starting amperage could be 50+ as it fires up
heater blower motor --that will be alot less-- 20amp will be fine
if you worried --then start at lower fuse and see if it blows

resistor is to give it 2 speed - if so you will have a 3 wire rad fan switch

13th March 2017, 13:44

Quote:

Originally Posted by axsaxoman

If this is a rad cooling fan --then 20amp is not much -look at thickness of wires on fan
30amp fuse not un common and starting amperage could be 50+ as it fires up
heater blower motor --that will be alot less-- 20amp will be fine
if you worried --then start at lower fuse and see if it blows

resistor is to give it 2 speed - if so you will have a 3 wire rad fan switch

Yes it's the radiator fan - just worried as I've bypassed the fuse block and taken the live from the battery. Unorthodox I know but wiring isn't my strong point!!
Will it be okay? just worried about the fan spinning faster than it's supposed to and burning out/catching fire!!

13th March 2017, 15:05

Changing the fuse won't adjust the voltage/amperage going from the battery to the fan. A fuse is a fail-safe, if the fan draws more than what the fuse is rated for, the fuse pops thus saving your wiring from burning up.

You need a variable resistor potentiometer (Or something similar) to adjust the fan speed.