Electrical advice on fan wiring.

Hello,

I recently bought a variac fan speed controller which I have wired and installed a single socket onto today. The problem is when I went to take off the speed controller built into the wire of my fan

This fan, its the 200mm version with 3 speed control.
https://www.somhydro.co.uk/products/ruck-can-fan-isomax-acoustic-3-speed-fans

So when I opened the speed controller(or switch) to take the wires out and put a plug on it there are two wires from plug to speed controller and 4 wires going into the fan from the speed controller. I previously thought it was just a cheap box which fluctuated the fan on/off at different speeds to control the speed but now I'm not sure with there been 4 wires.

The 4 wires are black/blue/green/white.

Seems to me I am not going to be able to wire this to a variac which only has live earth and neutral.

Does anyone with an electrical background have any thoughts on this?

I have linked the fan which is identical above because mine is boxed in apart from the wire. If needed I can reopen the built in speed controller and take a photo of that but it is basically a sliding switch with 2 wires for power and 4 wires other end with copper channels that the slide moves up and down on.

I'm a bit pissed off having had to wait nearly 2 weeks for the variac to arrive just to run into this complication.
I suspect my fan must have a speed controller within the fan itself, if that's the case there's nothing I can do about it because its constructed in a way that I cant open it.

Anyway thoughts from anyone who has an idea of what I am dealing with here would be appreciated.

Cheers.

Electrician here. What I would try without having the fan In my hand is leave the 3 speed controller on the highest setting. Or full speed. Take the hot and neutral and ground off the plug and hook it up to your variac. As long as it's on highest speed in the built in controller you should have full range on your variac. Good luck

Getgrowingson said:

Electrician here. What I would try without having the fan In my hand is leave the 3 speed controller on the highest setting. Or full speed. Take the hot and neutral and ground off the plug and hook it up to your variac. As long as it's on highest speed in the built in controller you should have full range on your variac. Good luck

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Cheers, I had thought about that as an option but I wasn't sure if the combination would cause a problem. Will give it a try. There's no earth on the plug part though just a live and neutral but I have seen diagrams with it not earthed.

Thanks for the response.