I have built up an old motor into a fair 10 inch disc sander. The motor was wired for 240 V, I could not figure out how to re-wire it. After a quick trip to the hardware store, I came home with an expensive (13 bucks) wall switch. A 4 way. The kid assured me it would work to switch on a 240 volt motor.
I think maybe shouldn't have listened.
Will this switch work? I tried it, but it was always "on", either way I flipped it, the motor ran. I followed the labeling on the switch, as to "load" and "source".
I would like to be able to turn both legs off at the same time. I understand that the motor would stop if I cut current to either leg. (after several Google searches.)
If I have the wrong switch, could someone suggest a better one?
Thanks!
Dan V.
Didn't find your answer? Ask the community — no account required.
G
Greg G.
Sure, go to your local electrical distributor, or even RadioShack and get a plain old DPST toggle switch. Make certain that the contacts are rated for use at 240 and are of a proper HP (or even amperage) rating.
Should cost you about $4.00.
3 and 4 pole switches are only set up to switch one hot lead.
FWIW,
Greg G.
G
Greg
Take it back to the store and tell them you want a double pole switch. It looks the same but it is wired differently internally. The one you have simply swaps the inputs. That is used in "3 way switch" traveller legs. A double pole switch opens both legs
So no matter what position the switch is in, it's still supplying current on both legs.
Yes, but it's *much* safer to cut current to both legs at once. *Don't* interrupt only one leg. It isn't safe. Do it right.
Take the 4-way switch back, and tell them you need a double-pole switch. Any hardware store that sells 4-way switches probably sells double-pole switches too. Although it looks about the same on the outside, it ain't the same on the inside. Here's how a double-pole switch works:
(ON position) (OFF position)
o-----------o o-----\ o \ \
o-----------o o-----\ o \ \
-- Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
D
Dan Valleskey
Yes- that is sorta what I was getting at.
Thanks Doug, and everyone else, I'll try to get back to the hardware store this afternoon.
-Dan V.
T
TeamCasa
Not so stupid. Get a switch that is rated for motor control. Don't fool around with cheap stuff that will cause you more harm than good. Unless you shop at HF, then never mind.
T
Toller
HD has one for about $8. It is green, if that helps you find it. 240v/30a. I just bought one for my DC.
R
Robert Bonomi
Some motors are 240 *only*. thus it may not be "re-wireable".
You *do* have the wrong switch.
The kid lied. Perhaps not intentionally. (The switch may be 'rated' for
240V, but it is -not- usable as a simple "On/Off" switch for two hot leads.
A '4 way' switch is used in multiple-switch (*more* than 2 switches) lighting circuits. It has 4 contacts, call them A, B, C, and D. A and B are the 'source' leads, C and D are the 'load'. When the switch is in one position, A is connected to C, and B is connected to D. In the _other_ position, A is connected to D, and B is connected to C. This works to turn on/off lights *only* when it is wired with a "3 way" switch on _each side of the 4-way one. one of those 3-way switches connects the hot wire to _either_ A or B, and the other 3-way switch connects _either_ C or D to the load. Thus _only_ A or B is 'hot' at any given time, and -only- C *or* D is connected to the 'load' at any given time. So, in one position, the light is on, and in the other it is off.
What you require is a "Double Pole Single Throw" (also known as "DPST", for short) switch -- which is, in essence, two 'regular' on-off switches "in parallel". It _also_ has 4 contacts, A, B, C, and D. But here is the difference: in one position, A is connected to C, and B is connected to D, while in the other position *nothing* is connected.
Take the one you have back, and demand a full refund. The employee mis- represented the product.
I'd think you should be able to get a DPST at that store. They tend to be somewhat more common than the 4-way ones. *HOWEVER* the price seems high for a regular 'toggle' type wall switch. About typical for a "Decora' style one though. I bought a regular style 4-way wall switch at one of the BORG a few months ago. I think it was $4.99. DPST should be in the same price range.
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required
Report Content
You are reporting this content to the moderators. They will look at it
ASAP.