Can I control a two-speed fan motor with a two-way light wall switch?

[senmeis]

TL;DR Summary

switch, motor

Hi,

I want to control a two speed fan motor with a two way light wall switch. The switch has L1 and L2 ports which can deliver power to two separate lights. The motor has two power terminals: speed 1 and speed 2.

Of course I mustn’t connect L1 to speed 1 and L2 to speed 2 directly because only one speed is allowed to operate. Is it possible still to use this switch by adding a control circuit?

 

[Tom.G]

TL;DR Summary: switch, motor

a two way light wall switch

The switch sounds like the right one for what you are doing.
It is a matter of getting the switch connections correct.

Can you tell us what markings there are at the switch terminals, if any.
Maybe a link to a website that shows or describes the switch
Also the make and model of the switch.

This information would help us help you.



Cheers,
Tom

 

[DaveE]

So your fan has three desired states: Off, High, and Low. Are you really asking how you can chose one of these three with a two position switch?

If you don't ever want to turn it off, it is quite straight forward.

 

[Nik_2213]

IMHO, you also need a way to locally fuse / isolate the device. So, a 'two-panel' task, with one panel providing fuse and power switching, the other selecting between fast / slow. If current draw is low, you may be able to do it with a single-wide 'wall box' using two plug-in 'face' modules. Better to 'Play Nice' and use a 'double-wide'...

 

[DaveE]

IMHO, you also need a way to locally fuse / isolate the device.

Why? In my house I have a circuit breaker for each branch circuit at the back of my house. This way I don't need to fuse each light, toaster, or vacuum cleaner. I find that really convenient.

I have a two speed fan over my stove with no fuse, do I need to fix that?

PS: Oh, I get it. You probably live in The UK, where distribution is weird.

 

[Nik_2213]

Does the fan over your stove also have an ON/OFF switch ? Or is it linked to an ON/OFF on stove ? Is stove hard-wired ? How to switch off / isolate fan without a hike to stove's breaker panel ??

I'm *concerned* that you are running a hard-wired appliance via a mere light switch, which could cause a future problem. At least an adjacent 'fused spur' panel warns, 'Huh ? That's weird...'

Okay, yes, our UK basics are *all* 220 V so must try harder, hence ring-mains, RCDs, double-insulated else grounded, plugs fused according to appliance draw, so 2A, 5A, 13 A etc etc. (Your 110 V equivalents would be 5, 10 and 25 A ?) Our industrial / site tools that run on 110 V via an isolating transformer do not need or use fused plugs...

 

[DaveE]

I'm *concerned*

I'm not. That's how we do it in Silicon Valley.

 

[senmeis]

This is a conventional 2-Gang wall switch on the market such as: https://www.amazon.com/Amerisense-O...tor-Standard/dp/B0BYCM75P7/?tag=pfamazon01-20. Each switch operates separately. When On, current will be delivered through this switch. When Off, , no power is available.

The only problem is when both are On. That is, Speed 1 and Speed 2 are powered on at the same time. I’m thinking if there is an additional module to exclude this.

 

[sophiecentaur]

You probably live in The UK, where distribution is weird.

Haha. You could start a fight with comments like that.
It's "different" is all you can say. One good thing about UK electrics is that you can expect to find the same arrangements wherever you go. (Assuming the DIYers have behaved themselves)

 

[Rive]

...only one speed is allowed to operate.

I'm not exactly sure about that. If it's the usual circuitry often used for cheap cooling fans then the high speed will be a direct connection, while the low speed would be through a cap. In such case linking them up won't cause harm.
A check on the actual circuitry would help a lot.

But, if the fan is for such use (with a remote switch), then there should be a wiring diagram somewhere, no?
And if it's not for this, then you just shouldn't, right?

...example:

 

[berkeman]

This is a conventional 2-Gang wall switch on the market such as: https://www.amazon.com/Amerisense-O...tor-Standard/dp/B0BYCM75P7/?tag=pfamazon01-20. Each switch operates separately. When On, current will be delivered through this switch. When Off, , no power is available.

That Amazon link is to the coverplates, not to a switch. Can you link to the actual switch(es) you are looking at using? It seems that break-before-make, SP3T switch is what you are looking for, no?

 

[DaveE]

Haha. You could start a fight with comments like that.
It's "different" is all you can say.

Nope. I could say more, LOL.

 

[senmeis]

Let me formulate the problem clearly.

I want to use a 2-way-2-gang switch to control a dual-speed fan motor. The switch has six poles on the back: L11, L1, L12, L21, L2 & L22. The motor has two terminals: High Speed and Low Speed. The idea: switch L1 is for overall On and Off and switch L2 is for selection of two speeds.

My connection looks like this:

External L line -> L1
L11 -> L2
L21 -> High Speed terminal of the motor
L22 -> Low Speed terminal of the motor

Is it so far correct? Do I miss something?

 

[senmeis]

This is my wiring diagram.

 

[Tom.G]

This is my wiring diagram.View attachment 339130

At least here in the USA, there are switches like that but have 3 positions, with the Center position Off.

A Google search
(https://www.google.com/search?hl=en&q=spdt+center+off+switch)
found:

https://www.google.com/search?&q=leviton+5685+site:amazon.com

Cheers,
Tom

 

[senmeis]

I can also find such two speed switches on the market, but I’d prefer my 2-way-2-gang switch because I need a squared switch panel. So does my wiring work at all?

 

[berkeman]

So does my wiring work at all?

It looks okay to me. You might want to show the Neutral connection as well, but I'm assuming that it just goes straight through the junction box to the fan.

 

[Nik_2213]

Don't forget safety earth-bonding to the box and, unless device double-insulated, to that, too...