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View Full Version : Have an electrical question maybe you can help me out.



samari46
05-06-2021, 12:57 AM
Have an old Harbor Freight band saw the kind that has 4 legs. Pretty sure it may be the switch or the capacitor. Switch is what appears to be a long toggle handled double throw double pole. So I'm guessing it shuts off both the hot and neutral wires. Either on or off. Has a longer than normal handle or toggle. When the saw finishes the cut a section on the blade part hits the longer toggle and shuts it off. I have a 10a 125 volt single pole double throw toggle switch with the longer toggle handle. Which is what the motor is rated for. Can I use this instead of a DPDT switch and just leave the neutral wire intact. Or do I need The DPDT and have it open both the hot and neutral?. Thanks in advance for your help. Frank

knifemaker
05-06-2021, 02:19 AM
Can you use a dremel tool with a small cut off blade to shorten the extra long toggle switch to where the saw blade will not make contact with it?

Mr_Sheesh
05-06-2021, 04:02 AM
If the hot and neutral wires are wired backwards (it happens!), opening both makes the device safer. And for the manufacturer, that looks like "best practices" plus lets them say, should it go to court, that they took extra care safety wise.

Plus if it has a plain unpolarized 2-wire AC plug, you never know which way it will be plugged in, so you WANT to open both live and neutral.

For your use, you can, barring that; just be aware that you want it plugged into ONLY sockets that are wired correctly. A tester for 3 wire sockets is pretty cheap, as well.

Unsure why you want to change it, did the old switch wear out? You don't say.

bakerjw
05-06-2021, 06:33 AM
Remember. This is Chinese junk equipment. I've purchased equipment like that before with a 3 prong plug only to find out that it was a 2 conductor wire.

If I trust the outlet wiring (which I do as I have rewired my complete house and garage) then I would go with a single pole switch. The best option though is a double pole switch. Lowes or Home Depot might have them in stock.

rancher1913
05-06-2021, 07:49 AM
without a volt meter and tracing the wires, its a shot in the dark.

jsizemore
05-06-2021, 07:57 AM
Most likely the same machine can be used for 120 or 240 volts. Hence the double pole switch. If you use it @ 120VAC, then hook the neutral straight through and switch the hot leg. If the unit doesn't have a ground, get one instead of yourself or people you care about. The others are on their own.

Mal Paso
05-06-2021, 08:50 AM
If it's 120V the other pole is likely the motor brake not a neutral. Lots of the new saws use the motor windings to slow the motor after you shut it off.

samari46
05-07-2021, 12:03 AM
Saw is dated from 2002. And the extra long toggle is what is contacted by the cutting unit when it comes down and shuts the saw off. This is one of the small 4 legged saws for cutting metal. Saw just stopped working during a cut. Instructions said if it stops working replace the switch if that fails replace the motor. Old Harbor Freight saw. Hope I covered every thing. Have a voltage tester so hopefully will see if I have continuinty when switch is in the on position. Hate to trash it if the motor is shot. Probably cost more to replace the motor than I paid for it in the first place. if the switch is bad will hit lowe's and see if they have one. Frank

MarkW
05-07-2021, 01:10 AM
Is the data plate with the model number still on the saw, what model # is it?

fixit
05-07-2021, 07:01 AM
Don't rule out an open circuit.... I have an H.F. vibratory polisher that up and quit, did some exploratory investigation, and found a wire had come loose from it's solder joint. Resoldered, and it's been working great for years since. Start simple and expand from there.

lksmith
05-07-2021, 09:35 PM
Have an old Harbor Freight band saw the kind that has 4 legs. Pretty sure it may be the switch or the capacitor. Switch is what appears to be a long toggle handled double throw double pole. So I'm guessing it shuts off both the hot and neutral wires. Either on or off. Has a longer than normal handle or toggle. When the saw finishes the cut a section on the blade part hits the longer toggle and shuts it off. I have a 10a 125 volt single pole double throw toggle switch with the longer toggle handle. Which is what the motor is rated for. Can I use this instead of a DPDT switch and just leave the neutral wire intact. Or do I need The DPDT and have it open both the hot and neutral?. Thanks in advance for your help. Frank

I've done similar on an OLD concrete vibrator. the switch opened and closed connection on BOTH wires. Switch failed, I had a SPST toggle on hand, so I put a butt splice connector on the neutral and wired the switch to the hot side. No problems yet

samari46
05-07-2021, 11:44 PM
Thanks all. Will go out to the garage and check to see how it's wired in the first place,then go from there. And check the model number as well. Was making a cut and heard a click and the saw stopped. Frank

samari46
05-08-2021, 11:17 PM
OK, made it out to the garage. Info is as follows. Central Machinery
Model 37151, MFG 2002, 14 amps, 1 HP 110 volts. Oh yeah, made in Taiwan if that makes a difference. Have to find the manual to see what size blades it takes. Frank

cobia
05-10-2021, 11:21 AM
Get it working!
How many wires are connected to the switch now? You should only need two typically, to break the hot wire only for 120v.

samari46
05-10-2021, 11:41 PM
Today and tomorrow will be running the streets. Wife is back from visiting one of our daughters. Gotta stock up on food. Will check asap. Frank

samari46
05-15-2021, 11:53 PM
Got the Harbor Freight saw running. Swapped out the switch but no joy. Then looked down at the power cord and looked like something was eating it. Single pole single throw switch only breaks the hot wire. Had some wire and a spare plug. Hooked everything up and away she went. Had to adjust the stop that pushed the toggle into the off position. Sometimes the least item can trip you up. Thanks for all your suggestions and comments. Much appreciated. Frank