Controlling a blower motor with 2 variable speed controls?

Thread Starter

MarkVTX

Joined Oct 29, 2018
7
I have a small A/C blower that has a variable speed knob on the blower housing itself. I would like to add another speed control to control the same blower from another location. Can I add another control without disconnecting the other one?
 

Dodgydave

Joined Jun 22, 2012
9,670
Only two options i can see, if its an ordinary light /speed dimmer then a simple two way switch between each dimmer will do.

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DSC_0121.JPG



Otherwise you are extending the control potentiometer to another location, and again using a two way switch on the wiper.


Ideally post a picture of your speed controller.
 

Thread Starter

MarkVTX

Joined Oct 29, 2018
7
I don't have a picture of the speed controller itself because it is mounted to the backside of a wood stove that is tucked into a fireplace and hard to access, hence the need for the second control. I believe the control is similar to this one. Could I leave the one on the unit on full speed and then add another to the circuit for the actual control or will problems arise?

Thanks
 

Reloadron

Joined Jan 15, 2015
5,667
Something you could do, if things will fit is use a pair of two way switches, one at each location. Here is an example of a two way switch you are likely familiar with. Note in the linked image L1 and L2. You would place a dimmer at each end so that would allow you to switch to the location the individual speed controller is located at, one at the stove and one at your remote location. The light in the link is just replaced by your blower motor. The same idea as being able to turn on a light from either end of a room. You would use a double gang utility box on each end, switch and speed control.

Ron
 

MisterBill2

Joined Jan 23, 2018
7,310
You can probably get away with just adding the external control in series with the power supply leads. But you would need to set one control at max to use the other one. At any rate, that very simple method is easy enough to try that it is worth the effort. And if it does not work, then you can add a switch to bypass one or the other. BUT I doubt that you will need to do that.
 

Thread Starter

MarkVTX

Joined Oct 29, 2018
7
You can probably get away with just adding the external control in series with the power supply leads. But you would need to set one control at max to use the other one. At any rate, that very simple method is easy enough to try that it is worth the effort. And if it does not work, then you can add a switch to bypass one or the other. BUT I doubt that you will need to do that.
That's what I was hoping, I just wanted some opinions because I don't want to burn out the motor since moving an iron stove to be able to replace the motor is not a great time.

Thanks
 

Reloadron

Joined Jan 15, 2015
5,667
You can probably get away with just adding the external control in series with the power supply leads. But you would need to set one control at max to use the other one. At any rate, that very simple method is easy enough to try that it is worth the effort. And if it does not work, then you can add a switch to bypass one or the other. BUT I doubt that you will need to do that.
I keep thinking about that and I can't think of a reason it wouldn't work. I never tried it but again, can't think of a reason it would not work. I also see it as a nothing to lose and everything to gain.

Ron
 

MisterBill2

Joined Jan 23, 2018
7,310
The series connection may even serve as providing the option of setting a maximum speed avilable with the internal speed control and having the limited speed available from the other control.
BUT I suggest that initially you pay close attention to the blower and see that it starts up when the controls are on. You do not want a condition of power on but motor not running. That would be very undesirable. So start out with the internal speed control on " max."
 
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