Kenlowe causing fuse failure Help Please !!!

Hi all

I have fiffed a Kenlowe cooling fan to the series this fan is a old style one which came out of a disco but appears to work fine .

I have wired it directly to the fuse board with no relays or resistors etc

The problem is when i turn the fan on the the fuse (35AMP) bends and after about 5 mins of running the 35 AMP fuse blows

I have replaced the fuse several times and each time after 5 mins the 35amp fuse blows again .

Whats wrong guys ???

Please help as i have a off roading event this coming weekend

Many thanks chris

anything pulling that amount of power really needs to be switched by a relay,i'm surprised your wiring hasn't melted.

even the 16" Kenlowe fans only pull about 20A so unless it's one of their old twin jobbies that can pull anything upto 50A I'd say there's a bearing about to seize as it deffo shouldnt be pulling that much juice

and deffo use a relay to turn it on

Aye as Big chaps says.

Cheers guy
I will try the relay first see if that cures it .

Now for the embarassing bit -

What sort of relay do i need ?
How many pins etc ?
Also where abouts does in go / how to you wire it up ?

Sorry for all the questions

many thanks chris

look in the general q's and answer bits - section there on relays.

4 pole 50A shud do ya.

That does seem a lot of power for a fan 400 watts.
May be a silly question but is the fan blade able to spin freely or is it binding ?

watts x volts = amps so a 400 watt motor at 12 volts is 48 amps.that's how i work it out on my r/c aircraft anyway.

The blades are running freely i just checked

If i up the size of the wire and used a 40 amp fuse would that be ok or is that not really the thing to do ???

you could i suppose but not good practice,there's not many switches capable of switching that sort of current without melting.

dont! - simple as that. wire it up through a relay, triggered by a thermostatic switch and an over-ride switch in the cab (to turn it off)

bigchap said:

watts x volts = amps so a 400 watt motor at 12 volts is 48 amps.that's how i work it out on my r/c aircraft anyway.

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bigchap look at your equation again.

If a 35 amp fuse is constantly blowing then 35x12=420 watt

its watts = volts x amps or
watts/volts = amps

so 400 watts = 35amps (closest aproximation)

the fan should state on it watt(sic!) it is rated at.

If not you will need to get an ammeter to record what max current drain is and choose a fuse slightly higher (+10%).

cao said:

bigchap look at your equation again.

If a 35 amp fuse is constantly blowing then 35x12=420 watt

Click to expand...

that's why i'm not a sparks,although i am good at generating them!,i quite often let the magic smoke out of electrical components!

If I'm honest. I do have quite a tinfull of that magic smoke myself.