DPDT Toggle Switch wiring for two fans

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kangaboy
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DPDT Toggle Switch wiring for two fans

Post by kangaboy » Thu May 10, 2018 11:47 am

Lets act like this is controlling two radiator fans for topics sake...(I'll delete this when I get it solved since its dealing with 110V, I just really need some help and you guys haven't let me down in the past)
So back story is this is a industrial hair dryer for a dog grooming setup, and its just two hefty fans hooked to a 110v socket via a dual pole dual throw toggle switch. The wiring shorted out and burnt the switch, along with the wire leads, so I couldn't just buy a switch and replace it. Had to cut new leads and the like. The dryer has two motors in it, and a "hi" and "low" setting with flipping the switch up or down. I figured one motor running would be low, and two motors running would be high (I may be completely wrong on this...maybe the fans are given different voltages somehow).

This is the drawing that I came up with to give one fan power with the switch down, and two fans power with the switch up. Does this make sense? I tried it last night and it didn't seem to work (now I'm thinking its cause I blocked the airflow intake)...but I feel like its wired correctly. I have 12/2 coming from the wall...so a white, green, and black. Each fan just has two black wires coming off them, one going to a brush on each side of the armature. Green is grounded on one of the fans.

Image
'74 Standard- 1776T, MS3X3
'76 Westy- Stock 2.0L L-Jet

Ol'fogasaurus
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Re: DPDT Toggle Switch wiring for two fans

Post by Ol'fogasaurus » Thu May 10, 2018 1:05 pm

I am sure that DaleM will be on to answer this but I think there should be a correction in your diagram.

just like switching a light, all you need is the common going to the black side of both fans (you don't need to switch it).

Using a 3 position switch (a central no load position, then the two up and down position switch. [I don't remember seeing a standard type of light switch like this for a long time. Most of the ones I remember seeing was done by a switch you turned by hand. The cover had a pointer on it.])

#1 (the upper position) can switch on both fans #1 and #2 switch the fans.

#5 post can switch on fan #2 separately and shouldn't be connected to post #1. They way you have it I think switching on #5 (the lower position) would cause both fans to run.

The green, as I remember is the ground to earth.

Reference:

https://www.electricaltechnology.org/20 ... ately.html

https://www.physicsforums.com/threads/c ... ch.317354/

https://www.pinterest.com/pin/127156389452216815/

Its not really easy which is why I remember the dial type switch being used.

Lee

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kangaboy
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Re: DPDT Toggle Switch wiring for two fans

Post by kangaboy » Thu May 10, 2018 2:44 pm

Ol'fogasaurus wrote:
Thu May 10, 2018 1:05 pm
just like switching a light, all you need is the common going to the black side of both fans (you don't need to switch it).
Something more along the lines of this?

Image
'74 Standard- 1776T, MS3X3
'76 Westy- Stock 2.0L L-Jet

Ol'fogasaurus
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Re: DPDT Toggle Switch wiring for two fans

Post by Ol'fogasaurus » Thu May 10, 2018 4:47 pm

I goofed; the common wire is the white wire and the load is the black wire (is been a long time since I talked to anyone about it, I just do it and don't think about it). "If 120 volts North America, and standard wire colours (sic), the white (neutral) goes to the large blade. Black to the brass screw, white to the steel screw and green/copper to the green screw is the typical configuration."

You switch the black wire and it goes on the brass blade/screw on the switch. The white wire in turn goes to the large/steel blade.

If you have a three position switch, either rotary, toggle or rocker the center position is/may be where the main power comes in (there should be instruction on hooking it up). The single fan setup in your case the black wire to the fan is hooked to the brass screw then to the single fan.

The two fan setup the black wire is hooked to the brass screws then to one fan with a jumper to the other fan (sometimes it is done in red). (remember, this is all from memory and I wish Dale were here).
three position switch.jpg
This is one of many types of 3-position switches I have seen, usually with instructions.
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kangaboy
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Re: DPDT Toggle Switch wiring for two fans

Post by kangaboy » Thu May 10, 2018 11:05 pm

I hooked up the fans and switch the way I drew it up in my second drawing. It seems to be working as intended. The key was as you mentioned in your first post, that the neutral wires from the fan can go directly to the neutral wires to the plug/outlet, and they don't need to be hooked to the switch. Thanks for the help. I knew I could always count on STF 😀
'74 Standard- 1776T, MS3X3
'76 Westy- Stock 2.0L L-Jet

Ol'fogasaurus
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Re: DPDT Toggle Switch wiring for two fans

Post by Ol'fogasaurus » Thu May 10, 2018 11:46 pm

Great! Sometimes we make things harder than they really are. :wink:

Lee

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Dale M.
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Re: DPDT Toggle Switch wiring for two fans

Post by Dale M. » Sat May 12, 2018 9:03 am

IF it's working now, don't fix it.....

Dale
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1970 "Kellison Sand Piper Roadster"

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