opine on switches

[1930artdeco]

Hello,

I need to replace a low-off-hi toggle switch for antique fan. Can anyone recommend a good quality switch not made in China? I know that is an oxymoron nowadays. But I can go to McMaster Carr anyplace else?

Mike

 

[nehog]

More information might be helpful, but any center off, SPDT should work. As to COO, you'll have to look around. Around here, I'd go to ESS in Manchester NH, but that's a bit of a drive for you!

 

[1930artdeco]

I have an antique table top fan where I believe the switch is going bad. When I switch the fan on, it hums for a second and the motor starts very slowly if at all. But if I start the blades moving then it runs fine (and man canit move the air!). It ran fine for awhile before this started that is why I want to change out the switch.

Mike

 

[frankush]

I would take the switch out first and test it with a meter. The best quality I've found is the McGill brand. You'll want to check the amperage rating of what you have. Many miniature switches have a very low amperage rating. The physical size of the replacement may also come into play as the larger amperage units are larger in physical size.

 

[2ManyProjects]

I have an antique table top fan where I believe the switch is going bad. When I switch the fan on, it hums for a second and the motor starts very slowly if at all. But if I start the blades moving then it runs fine (and man canit move the air!).

Now that you have provided a more complete description of the symptoms, I tend to doubt that the switch is your problem -- at least, not the primary problem. While it's not impossible for a switch to develop high series resistance, they USUALLY either work or don't work, no in-between.

Have you closely inspected the motor? Does it perhaps have a starting capacitor? If so, that is your Prime Suspect. If nothing else, I'd clean it thoroughly (blow out with compressed air, soak in some sort of solvent, blow it out again, then let it sit until ABSOLUTELY dry before letting it get anywhere near electricity). Fan motors tend to become badly laden with all sorts of guck, due to constantly having atmospheric contaminants pulled through them. And you did mention "antique"; so the bushings/bearings probably also deserve a very close look.

 

[nehog]

This sounds suspiciously like an old shaded pole motor with shorted turns. Does the motor get hot when it is (finally) running? If yes, then the motor needs to be re-wound. If no, check bearings for tightness, as these motors have virtually no starting torque.

 

[1930artdeco]

O.k. two things. I am NOT an electrical genious so how would I go about testing the switch? I have a meter, would I set it for volts, or ohms? Volts I can figure out, 120 ACmax, but what about ohms? And number 2, I did have to get into it and rewire it as the original cord was shot. So I will try a switch first and then take it to a shop to be checked out.

Thanks,

Mike

 

[2ManyProjects]

O.k. two things. I am NOT an electrical genious so how would I go about testing the switch? I have a meter, would I set it for volts, or ohms? Volts I can figure out, 120 ACmax, but what about ohms?

With the switch completely out of the circuit, you would be checking for continuity -- i.e., resistance, or "Ohms" -- in both positions. In the "Off" position, you should have infinite resistance (open circuit). In the "On" position, you should have essentially zero resistance; a very few milliohms is no big deal, and probably to be expected due to contact resistance and/or your probes making imperfect contact (but ONLY a very few milliohms).

And number 2, I did have to get into it and rewire it as the original cord was shot. So I will try a switch first and then take it to a shop to be checked out.

By "rewire it", do you mean that you re-wound the motor? Or simply that you attached a new power cord? In any event, I seriously doubt it is the switch. As "nehog" said, it is far more likely that the insulating varnish on the motor windings has degraded over time, and the coil is partially shorted-out internally.