Kenlowe radiator fan

[skelteanema]

Hi all,

I have been having intermittent problems with my electric radiator fan. Every now and then it will blow the fuse when I switch it on (it is only manually switched with no thermostat control). I decided to pull it out and have a look, but it is not a design of motor that I have seen before (not that I have much experience with electrical things).

The motor markings say Kenlowe, British made, 12 V, and direction indicator for when the positive is attached to each terminal. There are no other marking or model number. It looks to be of the correct period as my Elan (1967). I have not been able to find any information on this model of fan, or any that have similar internal design.

It was easy to split, four bolts and pry apart to break the magnetic pull. The inside was composed of eight fixed circular magnets on the housing and a disc rotor. The disc rotor had copper vanes/tracks on one side and brass veins/tracks on the other side. The only electrical connection was through two brushes that contact at different points on the copper side of the rotor, on the same side as the magnets.

Some of the copper tracks were damaged where they had clipped the magnets, but I managed to get them back in place and glued them down with super glue. I cleaned it all up and it is working, but not sure for how long, or whether I have fixed the problem.

Was this type of motor a typical fitment on our cars?

Can anyone shed light on how this type of motor works?

Thanks

[billwill]

I've never seen one like that before.Are the magnets on the spinning part, or are the coils on the spinning part?

Old-style DC motors usually have a commutator, brass contacts and carbon brushes, I don't see any there. Modern motors DC motors such as those in computer fans have a transistorized circuit to perform that function & so they are sometimes referred to as brush-less DC motors.


All motors draw a high current when starting, so any fuse should probably be, say, 5 to 10 times the running current rating.

[billwill]

Servicing any kind of DC motor is basically the same.

Clean it up

Regrease/re-oil any bearings

Use fine Wet & dry emery paper to clean the commutator contacts then be sure to clean away any specs of loose copper or brass.

Check the brushes & fit new ones if they are worn out.

Reassemble,

Check that it turns easily by hand.

Apply power.

[Andy8421]

Its a 'pancake' motor.

Clever design, uses printed rotor windings that double up as a commutator. I would imagine most modern equivalent fan motors are brushless, using electronics to generate a rotating magnetic field.

In your case, it looks like the rotor windings have been rubbing against the magnets causing an intermittent fault to earth - enough to blow the fuse. I would guess a thrust surface has worn somewhere allowing too much end float on the rotor, and the windings have touched the magnets.

Fixing the end float and making sure the windings are clear should solve the problem as long as the windings aren't too badly damaged.

Kenlowe were a well known aftermarket supplier of electric radiator fans, the original Lotus item was a repurposed Smiths motor with what looked like a propeller on the front. As yours it is non-original anyway, you could consider a modern replacement which would probably be more reliable.

Edit:

The original fitment wasn't exactly an example of elegant design.

[Barney]

I had a Kenlowe fan fitted to mine back in the early 80's, but when I started resurrecting my car I found it not working and replaced it with something a bit more efficient and also with a variable thermostat.

Sorry cant help with how it works.

[skelteanema]

Thanks for the replies, especially Andy for describing it as a pancake motor. With this description I found a video showing one in operation:

https://www.youtube.com/watch?v=IrsoE-j0DXo

I had not seen this design before, it seems very simple and surprising that it is not used more often.

I must say that my fitment is more elegant than that shown. I have a metal band that runs across the front of the radiator at the fan bolts directly to tis through the three bolt holes on the fan.

The problem was not the high current at satart-up as the fan worked most of the time, but occassionaly would not start rotating which led to a blown fuse. I have cleaned it up and put it back together and it seems to be working OK, but time will tell, as the fault was intermittent.

[billwill]

Interesting.