Neat twin cooling fan slow fast wiring

[oldtuckunder]

Meant to post this a week or so back when checking out the fan wiring on the Cosworth.

The rad has two fans, which are either off, slow speed or high speed.

If the AC is on then fans are always on at slow speed, if the coolant get up to temp then they both come on at high speed.

Whilst the AC function may not be very relevant the way they switch between slow and fast I though was rather neat and could be applied for different uses.

If the AC is on a relay connects power to the fans so that they are connected in series so that each fan actually only gets 6V and runs slow, when the temp sensors cuts in an additional supply connected in parallel is switched in and both fans get 12V and run fast.

Neat simple solution.

Alan

 

[JohnD]

I had to revise my engine rig, and positioon the radiator to the side, so went to the scrapper for a fan.    Got one out of a Transit, that's as wide as the rad, and has three wires, earth and a fast and slow supply.   The fast draws more than 15 and less than 20Amps!     But there's a curious coil inside the cowl with a control box behind it, only two wires to the fan.       Override for very cold or hot air?

John

[Nick Jones]

Coil is a resistor for the slower speed may be John? Cheaper than a proper dual wound motor.

Chris's Spit has a Mk2 Golf fan which is a true two speed fan switched by a twin contact switch in the rad side-tank. Plug and play. Not that we've ever known it need the higher speed which is really blowing quite hard!

Nick

[rogerguzzi]

Hello All

              I have 2 x 9" fans and a dual thermostat switch and relays

The hot one only comes on when stuck on a Spanish motorway and its 30+ degs!!!!!

Roger

[JohnD]

1 hour ago, Nick Jones said:

Coil is a resistor for the slower speed may be John? Cheaper than a proper dual wound motor.

Nick

Aaaaah!   Quick and dirty!  The fan can take away the coil heat!

J.