Bandsaw switch question

[b4man]

I just bought a new to me used bandsaw that was never converted to 240v from the shipped 110.
First thing when I got it set up was to rewire the motor. I noticed that when I push the STOP button it reduces power but will not stop until I press it again. This has me puzzled. I am not aware of having to reconfigure the switch as well but do I need to?

Any help would be much appreciated.


Barbara

 

[JackLeg]

What brand saw is it? Is it possible that you've got a 2 speed switch? Sounds like you're not fully breaking the circuit. :wsmile::icon_scra

 

[b4man]

Rikon. Reg, you're right about it seeming to not break the circuit completely. I thought the same thing. It's a standard push switch.



Barbara

 

[Mike Davis]

Very strange...

Sorry I'm no help. You know a lot more about electrical than I do.

 

[jhreed]

I am going to jump in here assuming that ALAN AT LITTLE WASHINGTON will correct me if I am wrong. 110 volt typically has 3 wires. One hot, one neutral, and one ground. You only break the hot line, just like a light switch in your house. With 220 volt you have two hot, one neutral, and one ground. You need to break both hot wires. So, instead of a single pole switch, you need a two pole switch.

 

[ehpoole]

I am going to jump in here assuming that ALAN AT LITTLE WASHINGTON will correct me if I am wrong. 110 volt typically has 3 wires. One hot, one neutral, and one ground. You only break the hot line, just like a light switch in your house. With 220 volt you have two hot, one neutral, and one ground. You need to break both hot wires. So, instead of a single pole switch, you need a two pole switch.

You do not need a double-pole switch to break a 240V circuit (properly wired the current flows from one hot to the other, break just one and power is cut). However, from a personal safety perspective it is not a bad idea to use a double-pole switch to ensure that no part of the motor's wiring remains hot should a novice start tinkering with the wiring while the unit is still plugged in.

However, the above may be half right. From the description of the problem it does sound as though the rewiring of the motor for 240V may have been done improperly with the ground wire possibly being wired into the motor windings. This would allow a remaining hot wire to run 1/2 of the motors windings by delivering its power to a field improperly wired into the ground conductor. Verify that the motor was properly converted to 240V. The ground wire should only connect to the motor chasis and should not be connected to any of the motor's winding connections.

 

[aplpickr]

220 volt is two hots and a ground, no neutral needed, unless a 120 volt load is used. If a 120v light is used, you will need a neutral. Sounds like you are using 220v (on position) and 120v (off position). That does not explain the double click to turn off. How about a wiring diagram or picture. How did you get 220v into the original male plug?

 

[mkepke]

If you have the documentation for the saw (or can find it on the 'net), see what it says about switching over to 240V operation.

IF the saw - and not just the motor ! - was designed for 240V operation, I would expect it was shipped with a double pole switch and was wired so that both leads (hot + neutral in 120V operation; hot1 + hot2 in 240v operation) would make/break together. But this should be obvious from the documentation.

If no documentation, remove power and crack open the switch box and see how the switch is wired. It may be labelled with a wiring diagram. Or you can deduce operation of the various terminals using an ohmmeter.

Worst case, junk the switch and go buy a 240V machine rated switch for <$20.

BTW, there is no neutral in a 240V, 1ph circuit. A neutral would indicate a multiwire circuit supporting both 120V and 240V devices.

-Mark

 

[b4man]

Let me try to address all the questions.
The doc's have a standard schematic for connecting both voltage uses.

I disconnected the red and blue wires from the black and white wire connections and connected the whites together, etc. I joined the blue and red wire to each other. The Green/ground wasn't touched.

Not only did I do as the directions say, I did as i've done before many times when converting my equipment.

I plan to go out there now and see what's behind the switch box. I doubt the switch has ever been removed and it's as it came from the factory.

Thanks guys.


Barbara

 

[aplpickr]

What is the model #? Perhaps you have a non-original motor. Is it a dual voltage motor installed in a single voltage machine. Amen to connect the green only to the FRAME of machine and/or motor. REMEMBER: WHEN YOU LET ALL THE SMOKE OUT OF IT, IT WON'T WORK NO MORE! Be sure you let us know after you have electrocuted yourself! :gar-Bi

Please get someone, with knowledge and a volt meter, to help you.

 

[Mike Davis]

Bill,

Barbara used to be an electrical contractor. She knows more than most about the stuff.

 

[aplpickr]

Barbara, I apoligize. I get very frustrated trying to fix electrical problems on the net. Usually a picture or a little more knowledge helps greatly. There is always the danger factor involved! It is a fine line between helping and getting someone hurt. :gar-Cr I used to do restaurant repair. A store manager wired the hot wire to the frame of a stainless rolling cart with rubber wheels in a BurgerKing. It was OK until I touched it and the metal counter at the same time. When my reaction pushed it into the counter, it melted a silver dollar hole in it!

Foreign color codes are showing up in imported stuff. Blue neutrals and brown grounds. How about NZ which uses pink, orange, and yellow?

 

[ehpoole]

Barbara,

If you do not find your answer in the switch, please do not hesitate to give Rikon a call. Their support staff are both friendly and knowledgable. Just be sure to call from your cellphone or a cordless phone becuase they will likely want to talk to you while you are standing at your bandsaw describing what you see and/or make specific changes.

Good luck,

 

[Alan in Little Washington]

Since I was mentioned, might as well throw in my two cents-

First, most of the responders hit on possible causes. The two that seem plausible are (1) motor is running on one leg of 220 and ground during shut-down - on 110V, or (2) it is a dual voltage motor.

But neither match the reported symptoms which are a real puzzle. It must be the switch.

I assume this saw does not have a mag starter, though this problem could exist with one of those also. The key issue is that Barbara says the first time she hits the stop button the motor keeps running, but on reduced power and it doesn't stop until she hits stop again. I don't know any machine switch that works that way. The switch either passes power or it doesn't, unless it has bad contact(s), bad spring, or carboned up contact, then it could be arcing and sparking inside and not supplying full current to the motor. Allowing that to continue can cause the contacts to fuse and/or cause a fire.

One other situation is that the motor has a short or is wired incorrectly AND the switch is bad- one of two contacts is not opening so one hot lead is still connected to the motor AND the ground is incorrectly wired to the motor causing it to run on 110V. A similar situation could occur if one hot lead and the ground are switched, one hot goes directly to the motor and there is a switch problem.

I would first disconnect the motor and test the switch. If you don't have a meter, use a light bulb between each hot, one at a time, and ground (if both hots are switched). Operate the switch multiple times. If the switch is good, then you know to check/re-wire the motor. You can test the motor without a switch- wire the motor directly to the 220V cord.

 

[Gotcha6]

Barbara, if the switch and motor are original to the saw then the switch should be a DPDT (double pole double throw). It may have had one set of contacts bypassed when wired for 120v as most manufacturers do not open a neutral with an on/off switch. In any case, all energized conductors to a motor or other device should be interrupted with a control switch or disconnect. It is not recommended to interrupt a neutral for control purposes (unless ya just unplug it!). Your need to push the stop button a couple times may indicate a faulty rocker switch not interrupting the circuit in a timely manner. These switches are made to force contacts to jump apart to prevent unnecessary arcing.
'course, you knew that already. :icon_thum

 

[Woodman2k]

I'm gonna jump in here cause I sold the band saw to Barb last weekend. The switch is good, the motor is good , and the machine ran perfect on 110 as it was shipped to me.The motor being dual voltage has to be rewired although I don't have access to the schematic so I can't tell you( Barb ) what needs to be done.If you can scan and email me copy of the schematic I will gladly figure it out.Give me a call on my cell if there is anything I can do tonite.
Greg

 

[b4man]

@ Greg, I sent you a PM.

@ All who were kind enough to answer, thank you for your concerns and your suggestions.

I was unable to get back to the problem today but will put a meter on the switch in the morning. If I can't find issue with the switch configuration I'll call Rikon.

BTW, this is a honey of a saw. If anyone gets lucky enough to find one used for sale, grab it.


Barbara

 

[Alan in Little Washington]

We are all curious.

In defense of all concerned, electrical problems are some of the hardest to troubleshoot, and even harder without being able to put "hands on." Intermittent problems are some of the worst. Sometimes all conditions and/or symptoms are not provided or not reported correctly, because they happen so quickly, seem irrelevant, reported in non-standard terms, etc. I'm not saying that is the case here, but it is one of those things that happens.

It is like one person referring to a neutral as a "white" wire. Sometimes that is the case . . .with 110V house wiring, but the same wire can be used for 220V then the white will be another hot (though code requires it be marked with banding or paint at each termination). In the case of a machine a typical rubber SJ power cord will also usually have black, white and green wires. When used for 220V both black and white will be hot. But, depending on the cord, the hot leads could be black, brown, red, blue, etc. As far as motors, the internal wiring usually has numbers somewhere on it, either printed right on the insulation, or on an applied band. That is what you should use to wire it for 110V/220V and to change the direction of rotation. The leads from the start capacitor may or may not have numbers. I don't think there is any standard for internal motor wiring colors. The switch may have different colored wire all together. All bets are off if the motor was rewired.

Now, back to the original problem as described by Barbara- The double push of the off button is a still a puzzler to me. She never said if it was a mag starter or mechanical switch. This is a pure WAG, but if a mag switch is wired improperly (read really weird) it might be possible for the decelerating motor and the reverse EMF if generates to re-energize the contactor coil and attempt to start the motor again. Barb didn't say what the interval was between activations of the stop button.

Anyway, I'm dying to know the answers.

 

[aplpickr]

Barbara: What did you find out? Curious minds want to know.

 

[b4man]

The question remains. The switch legs both read 115volts. It was wired according to spec's. When I ran the saw with the switch dismantled it stopped on the first push. Slowly the blade stopped but there was no current passing thru. I remounted the switch and it is stopping for now. I say this because I really believe it's in the switch and instead of waiting for the next time if there is one, I'm going to replace it.

Thanks again for the help everybody.


Barbara