Fan Fail F....

[Mike Pass]

On the way back from the Oulton Park Gold Cup one of my radiator fans died. It was subjected to the usual English post mortem examination. It seems that a combo of a lot of carbon dust from the commutator brushes and a few scratches on the armature disc had allowed some unwanted shorts in the motor case which then blew 30 amp fuses in short order.
Question is - now I have decided to get two new fans, what to buy and how to wire them up.
It seems that the more powerful fans take a lot of current so may need separate feeds, fuses, relays etc and maybe separate thermostats. The fans I had took about 12 amps each and produced a good blast of air through the rad, however the Kenlowe high power two stage ones can take up to 24 amps each on the high setting which by my calculation means 48amps draw!
I would be interested in your ideas and opinions and experiences of setups as it is impossible to try them all out and I would like to get the old girl out again before the evil winter closes down fun for the year.
Merci mes Amis
Mike

 

[Mike Pass]

The upshot is that I got two new Spal fans from Mick Sollis.Thanks Mick! Now back up and running again. I will upgrade the electrics later with a new electronic thermostat, relays etc.
Anyway here are some pics of the inside of the old Spal fan which died after many years of hard use. The cause of the failure was the carbon dust from the brushes rubbing against the armature and then shorting the current to the metal case causing the fuse to blow and the fan to no go.
Anyway here are a couple of pics of the motor interior showing the 4 ceramic magnets, the disc shaped armature and commutator. When pulling one apart note that the steel case acts to complete the magnetic circuit and this holds the case together pretty strongly even when the screws have been removed. The new fans may be somewhat different inside but I am not dismantling them yet!
Cheers
Mike

 

[Paul W]

I've got the Kenlowe two stage fans that do suck a lot of amps - I only run them on the slower speed cable and that is more than enough to keep temps in check. They are on a separate large style 40A fuse with pretty heavy cable. I use one of these to power them and it means I never really notice them running. The temp sensor is just attached to the output pipe of the radiator en-route back to the block.
Constant Temperature Controllers and Accessories
I have sat in heavy traffic, in full sunshine 30+ degree heat, with the AC running and the engine hasn't gone over 85 degrees.