# new switch for a shop vac motor



## lenaitch (Feb 10, 2014)

A lot depends on what type of motor you have. I would attempt to replicate whatever wiring and switch originally installed. Are there more than the black/white 'in and red/red 'out' in your diagram's "shop vac wires" box? There is usually more than one motor wire connected to the switched hot supply and usually, a switch only controls the hot side of an ac circuit with the neutral (supply cord white) connected directly to a motor wire. If it is a normal single-phase ac motor, you should only have a single-pole switch; i.e. 2 connection points (screws) - supply hot in and switched hot out. The neutral is not normally switched. If your vac has a dc motor it gets more complicated.

Either way, you should be able to source a switch better suited for machine installation rather than one intended for structure wiring mounted in a device box.

I'm kinda at world's end in my knowledge of motors here - maybe others will chip in.


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## de-nagorg (Feb 23, 2014)

I believe that you bought the wrong switch.

The specs for the correct one should be in the side of the old one, I used to take the old switch to RADIO SHACK and find a suitable replacement, but they are out of business.

So now your best chance is to find a vacuum repair shop locally, go there with old switch, They have access to all you will need, might need to order it, but you will get what you need.


ED


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## gramps4 (Jul 1, 2016)

> I believe that you bought the wrong switch.
> 
> The specs for the correct one should be in the side of the old one, I used to take the old switch to RADIO SHACK and find a suitable replacement, but they are out of business.


I believe shop vac motors are universal motors.

If life were only that easy. are you sure it is the wrong switch? I have seen others on the internet complain about these switches (7min 25sec into video). 



 Others have used other switches that are superior to the existing specification. In this case, the specification for this switch _sucks _since they are of poor design. Yes, _sucks_ is the technical term.


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## 39032637 (Dec 24, 2016)

OP -- the x-pole switches avail commercially will likely all exceed the design/quality specs of the original in your vac, the difficulty is (obviously) the physical mounting. 

Not sure if your vac has a separate ground? (Always preferred).


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## gramps4 (Jul 1, 2016)

39032637 said:


> OP -- the x-pole switches avail commercially will likely all exceed the design/quality specs of the original in your vac, the difficulty is (obviously) the physical mounting.
> 
> Not sure if your vac has a separate ground? (Always preferred).


Mainly the reason why i wanted to use this switch is i like the toggle action of these type of switches.

There is a separate ground that is mounted on the motor.


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## hkstroud (Mar 17, 2011)

> Which wires are supposed to be attached to which terminals?


Incoming (black and white) wired to one side of the switch and the motor wires (red) are connected to the other side of the switch.


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## Oso954 (Jun 23, 2012)

> Incoming (black and white) wired to one side of the switch and the motor wires (red) are connected to the other side of the switch.


Are you positive about that ?

I haven't used that switch and can't seem to find the instructions for it on the P&S site, but that is contrary to the 2 poles I have used.

I'd put a continuity or ohm meter on the terminals to be sure.


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## gramps4 (Jul 1, 2016)

Oso954 said:


> Are you positive about that ?
> 
> I haven't used that switch and can't seem to find the instructions for it on the P&S site, but that is contrary to the 2 poles I have used.
> 
> I'd put a continuity or ohm meter on the terminals to be sure.


I am not sure what i should be looking for when doing such a test.
I would have been nice if the terminals were labelled by the manufacturer.


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## FrodoOne (Mar 4, 2016)

gramps4 said:


> I am not sure what i should be looking for when doing such a test.
> I would have been nice if the terminals were labelled by the manufacturer.


In the OFF position, no terminal will connect to any other.
In the ON position either 
1 & 3 and 2 & 4 will be connected OR
1 & 2 and 3 & 4 will be connected. 

(Numbers are as shown in YOUR diagram).


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## gramps4 (Jul 1, 2016)

FrodoOne said:


> In the OFF position, no terminal will connect to any other.
> In the ON position either
> 1 & 3 and 2 & 4 will be connected OR
> 1 & 2 and 3 & 4 will be connected.
> ...


are you suggesting that i can choose or that there are only two possibilities?


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## FrodoOne (Mar 4, 2016)

gramps4 said:


> are you suggesting that i can choose or that there are only two possibilities?


There is another possibility (which is quite unlikely) but one of those two are the most likely.

In any case, an Ohm meter will indicate what the situation is.


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## gramps4 (Jul 1, 2016)

FrodoOne said:


> There is another possibility (which is quite unlikely) but one of those two are the most likely.
> 
> In any case, an Ohm meter will indicate what the situation is.


and what exactly what would i be measuring or looking for?


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## FrodoOne (Mar 4, 2016)

gramps4 said:


> and what exactly what would i be measuring or looking for?


I can hardly believe that you are being serious but
an ohm-meter will tell you if (or if not) there is continuity/connection between any two points/connections.

In the OFF position, no "connection" should connect to any other "connection" of the switch.
In the ON position, those "connections" which are connected are connected - by the switch.

What else can I say?


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## gramps4 (Jul 1, 2016)

FrodoOne said:


> I can hardly believe that you are being serious but
> an ohm-meter will tell you if (or if not) there is continuity/connection between any two points/connections.
> 
> In the OFF position, no "connection" should connect to any other "connection" of the switch.
> ...


I know how to do a continuity test with my multi meter and have done that many times before. I was just trying to clear up the intention first to understand the results. 

I have now done the tests and determined that in the closed position "ON" terminals on the left side of the switch are connected, and vice versa with the terminals on the the right side of the switch.

Is it possible to determine which pair is "hot/neutral" or "red/red" side?


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## Oso954 (Jun 23, 2012)

I hope you meant that the right side terminals also had continuitity when the switch was on, and none when the switch was off.

As far as connections, unless you have a good reason why you want to switch the neutral, I would not put the white on the switch. I would simply wire nut a red to it. 
Put the black wire on the bottom left and the remaining red on the upper left.

Plug it in, turn it on, check the airflow. If the airflow is backwards, flip the position of the two red wires.


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## gramps4 (Jul 1, 2016)

> I hope you meant that the right side terminals also had continuitity when the switch was on, and none when the switch was off.
> 
> As far as connections, unless you have a good reason why you want to switch the neutral, I would not put the white on the switch. I would simply wire nut a red to it.
> Put the black wire on the bottom left and the remaining red on the upper left.
> ...


they both had continuity when on.

so in the method you are suggesting, that would be just a single pole switch rather than a double. I am hesitant to possibly change the functionality of the motor without knowing the repercussions of such a choice outside of the motor spinning in reverse.


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## hkstroud (Mar 17, 2011)

> Plug it in, turn it on, check the airflow. If the airflow is backwards, flip the position of the two red wires.


That would only be true if this were a DC motor and circuit.

Either red can be connected to the neutral (white) with the hot (black) going through the switch and connecting to the other red.


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## gramps4 (Jul 1, 2016)

the thing that is most puzzling to me is if a single throw switch is satisfactory, why would a manufacturer make a double throw switch instead.


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## hkstroud (Mar 17, 2011)

The motor used will probably fit different models. Probably works on 120 or 240V. Assembly line (unskilled) worker only has to plug wires in. No thinking. Probably different rules in different countries. Efficiency in assembly.


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