Cooling Fan, best control method for Kenlowes ?

[GeraintUK]

Evening all,

I've got a new alloy rad going onto the race car build and as such I have a pair of 10" Kenlowe fans to fit.
This means i'm losing all he MGR Fan/Cowling assembly.

Question I have :

Is there an easy way to wire this up to the existing circuits. If so, is the control box required.
I'm happy enough to only have a simple trigger on and off and not worried about different speeds etc given the car's use.

I do have an alternative where I can use an aftermarket trigger, literally a temp sensor in the pipework which fires off a relay triger at X degrees C and i've used these before. Just if I could directly connect into the MGR loom without all the fan control unit it would be a simpler and neater setup.

Any thoughts/advice please.

Thanks
Geraint

[SD1too]

Originally Posted by GeraintUK

Is there an easy way to wire this up to the existing circuits.

I understand from Jules that the Kenlowe fan he supplied is best used with the car's original control box and relays. This method would certainly appear to be the most reliable since we know how it works and it hardly ever gives trouble.

Simon

[GeraintUK]

I did see that, but not sure my Kenlowe fans support twin speed. He uses a single large one which may be specced to do that whereas mine are 2 x 10" ones.
I guess i'm just looking to understand where i'd connect the live and earth to on the fan control unit. Is it really that simple.
Like I say, no real need to have multi-speed as it's track car mainly so happy to just have the fans trigger at say 105degrees.

Thanks
Geraint

[SD1too]

Originally Posted by GeraintUK

I guess i'm just looking to understand where i'd connect the live and earth to on the fan control unit.

Give me half an hour or so and I'll tell you.

Update
OK Geraint, at the moment does your fan have a resistor and two wires leading from the motor or no resistor and three wires leading from the motor?

Simon

[Sector-9]

You can make your own relay box (need about three relays) and that will give you two speeds from your new fans. For low speed, the relays would connect them in series, and for full speed it would connect them in parallel. For this you'd need one standard relay, and two change-over types.

[GeraintUK]

it's currently got a gold resistor on from Jules.
Could I just splice straight off that ?

sorry for all the questions, the fan control unit has always had me baffled.

ta
g

[SD1too]

Originally Posted by GeraintUK

... no real need to have multi-speed as it's track car mainly so happy to just have the fans trigger at say 105degrees.

OK Geraint, your existing MG Rover motor has two wires leading from it: red (live) and black (earth). If you simply cut these and connect your Kenlowe assembly in place of the existing motor you will retain the original 2 speed operation using the gold resistor. This is the easiest method of connection.

To dispense with the 2 speed arrangement and have your Kenlowes operating at full speed as soon as the coolant reaches 104° proceed as above then continue as follows:

• Inside the control box, locate the thin blue wire on the small relay (centre position) and disconnect it.
• Similarly, locate the thin blue/red wire on the large relay and disconnect it. Insulate this wire's terminal and tuck out of the way.
• Now connect the thin blue wire to the vacant terminal on the large relay.

What I have done here is to ensure that your larger relay (greater current capacity) is being used for your Kenlowes. The smaller relay will be out of circuit.

You'd be wise to check the wattage of your Kenlowes and therefore the current they will draw. The MGR large relay is rated at 40 amps continuous current at 85°C, falling to 17 amps at 125°C. If your Kenlowes draw significantly more than 450 watts then we will need to modify the circuit so that both relays share the current draw. The maximum current which both MGR relays can safely control is 55 amps at 85°C.

By the way, you say that your Kenlowes are 10 inches diameter. They're tiny! Have you seen the size of the standard MG Rover fan? It's huge, and there's a reason for that. Most of the aftermarket electric fans just cannot shift the volume of air necessary, so do make sure that you have selected a model which can cope with your proposed use on the racing track.

I do hope that I haven't confused you too much.

Simon

[GeraintUK]

Thanks Simon, you are a star