Troubleshooting no power to bandsaw

[derek labian]

I received this SCM bandsaw (S 640P) with a damaged bell housing. I adjusting the housing enough to allow fan to spin freely. The motor spins freely so it seems like no other damage. Unit does not power on. It has no lights to indicate power either, just a magnetic switch it appears. I wired up 3-Phase power in the same configuration as the FS41ES which works perfectly.

This picture shows the emergency button, and the magnetic switch.

IMG_9008.jpeg

This shows the secondary emergency switch.

IMG_9009.jpeg

This shows the switches that come off the main power, as far as I can see these are the only two. One feeds the 2nd Emergency button, and one feeds a button attached to the break ensuring the break is not depressed.

IMG_9010.jpg

There is also a microswitch on the door to ensure its closed. I opened up the microswitch and checked the continuity. It works fine.

The manual says nothing about any of this really, I assume they assume you know what your doing. I tried the emergency switches in both the pulled and resting state. It seems like they should be in the pulled state unless its an emergency.

Unless anyone has some ideas about something I could be doing wrong, my next step is to open up the control panel and check the continuity of all the microswitches and buttons.

I am trying to test the unit without the table installed so I can ensure the motor just runs. I don't see any sensor for a blade etc. A power light sure would be nice!

[Bill Dufour]

I would assume one of the stop switches is open. Normally all the stop switches are run in series and opening any one will break the circuit dropping out the contactor coil. I t can also be the auxiliary contact on the contactor that is also part of the stop circuit.
What voltage is the coil? What input voltage is the transformer set for?
Use a clean dry wood stick and push the contactor closed. The motor should spin up to speed as long as the stick is pushed. Let go and it may or may not stop. Be prepared to pull the plug or throw the breaker to stop the motor.
Do you have native three phase supplying the shop? which leg is powering the transformer.
Bill D

[derek labian]

I would assume one of the stop switches is open. Normally all the stop switches are run in series and opening any one will break the circuit dropping out the contactor coil. I t can also be the auxiliary contact on the contactor that is also part of the stop circuit.
What voltage is the coil? What input voltage is the transformer set for?
Use a clean dry wood stick and push the contactor closed. The motor should spin up to speed as long as the stick is pushed. Let go and it may or may not stop. Be prepared to pull the plug or throw the breaker to stop the motor.
Do you have native three phase supplying the shop? which leg is powering the transformer.
Bill D

Yeah, I assume one of the switches in the series is open, but I'd need to test each one which involves opening it up. I'm looking for any advice BEFORE I open it up and test each microswitch.

[derek labian]

What voltage is the coil? What input voltage is the transformer set for?

It's 220v, there is a big label on the electrical connection and my 3-phase converter is the same.

[derek labian]

Use a clean dry wood stick and push the contactor closed. The motor should spin up to speed as long as the stick is pushed. Let go and it may or may not stop. Be prepared to pull the plug or throw the breaker to stop the motor.
Do you have native three phase supplying the shop? which leg is powering the transformer.
Bill D

I'm not sure what your saying here Bill. I didn't think there was a transformer on the saw, just a strait feed to the motor with a few microswitches in between the main contactor.

[Bill Dufour]

I had assumed it was low voltage controls with a transformer supplying the low voltage. I am surprised a European machine has 220 volts at the controls.

[Bill Dufour]

You should be able to test all the stop switches at once from the contactor. This will prove or disprove they are the problem. Unless there is a safety switch that stops the power if the control box door is opened.
In my limited experience a brake switch can be out of adjustment. On my lathe I have to use my toe to lift the brake pedal from time to time. Only to get it running never during a cut.
Bill D

Simply jumper around each switch in turn to narrow it down. Good luck if it two switches gone bad at the same time.

[Malcolm McLeod]

...
The manual says nothing about any of this really, I assume they assume you know what your doing. I tried the emergency switches in both the pulled and resting state. It seems like they should be in the pulled state unless its an emergency.

Unless anyone has some ideas about something I could be doing wrong, my next step is to open up the control panel and check the continuity of all the microswitches and buttons.

...

I'm guessing you meant this, but just to be sure, does the main contactor engage when you press start? If it does the issue is probably in the 3-phase feed power, not the control circuit. ...Perhaps obvious, but I gotta ask.

So on to the control side - -
What is the starter/contactor's coil voltage? It will be printed on the coil (fed from terminals A1 & A2 on the contactor). It will also determine if there is a control power transformer. If so equiped, my experience is that 80% of issues are with blown fuses - either on the '2-phase' feed to the xfrmr primary (input), or on the 1-phase secondary (output).

Does the control wiring look like it may have been modified previously? Mismatched wire gauges, colors, terminations, wire nuts, etc....??

Further testing will involve working on the system 'live'; please be cautious, take the blade and belt(s) off:
Sounds like you have a multimeter. Does the manual include any electrical schematics? If so, identify the source of the control power voltage, then check that wire in the panel for proper voltage (to ground or neutral). Then go to each subsequent wire exiting a device (microswitch, button, e-stop, etc.) and repeat this test, pressing the 'Start' button each time once you test up to and then past that point on the schematic. When there is no power, the issue is in the device immediately upstream. After testing switches on doors or access panels that need to be open, tape that switch down, so that it passes power to the next device in the circuit.

In a complex circuit, you can shorten the time, by starting your test in the middle of the circuit. If that point has power, you know the circuit 'upstream' of the test point has power, and so the issue lies farther along the circuit. So, test the 2nd time 3/4 of the way along the circuit (or 1/4, if no power at 1/2). Rinse and repeat ~3-4 times and you will have isolated the problem device. (:: the law of halves.)

Schematics make this MUCH easier, but you can do the same by following the wire and testing this control power path.

Edit: Yes - - the E-stop buttons should be 'press to open' :: breaking the circuit to the coil; pull to reset (closed).

[Bill Dufour]

A picture of the contactor would help.
Bill D.

[derek labian]

A picture of the contactor would help.
Bill D.

Thank you for all the feedback, but I am looking for advice BEFORE I opened up the unit, such as anyone with knowledge of an additional microswitch for saftey, or information on how the power switch SHOULD work. For example, it appears to be a spring loaded switch that must be held in place when powered on? It simply falls back to off after turning to on. I assume this is as designed, but again, this is the kind of information I'm looking for. The emergency stop buttons should be pulled outwards I assume, but again, nothing in the manual.

[derek labian]

Edit: Yes - - the E-stop buttons should be 'press to open' :: breaking the circuit to the coil; pull to reset (closed).

Thank you.

I'm guessing you meant this, but just to be sure, does the main contactor engage when you press start? If it does the issue is probably in the 3-phase feed power, not the control circuit. ...Perhaps obvious, but I gotta ask.

So on to the control side - -
What is the starter/contactor's coil voltage? It will be printed on the coil (fed from terminals A1 & A2 on the contactor). It will also determine if there is a control power transformer. If so equipped, my experience is that 80% of issues are with blown fuses - either on the '2-phase' feed to the xfrmr primary (input), or on the 1-phase secondary (output).

Does the control wiring look like it may have been modified previously? Mismatched wire gauges, colors, terminations, wire nuts, etc....??

Further testing will involve working on the system 'live'; please be cautious, take the blade and belt(s) off:
Sounds like you have a multimeter. Does the manual include any electrical schematics? If so, identify the source of the control power voltage, then check that wire in the panel for proper voltage (to ground or neutral). Then go to each subsequent wire exiting a device (microswitch, button, e-stop, etc.) and repeat this test, pressing the 'Start' button each time once you test up to and then past that point on the schematic. When there is no power, the issue is in the device immediately upstream. After testing switches on doors or access panels that need to be open, tape that switch down, so that it passes power to the next device in the circuit.

In a complex circuit, you can shorten the time, by starting your test in the middle of the circuit. If that point has power, you know the circuit 'upstream' of the test point has power, and so the issue lies farther along the circuit. So, test the 2nd time 3/4 of the way along the circuit (or 1/4, if no power at 1/2). Rinse and repeat ~3-4 times and you will have isolated the problem device. (:: the law of halves.)

Schematics make this MUCH easier, but you can do the same by following the wire and testing this control power path.

I just wired the 3-phase power which I'm sure is correct. It seems unlikely something is wrong internally, the unit is brand new and must test these before shipping out. I do have schematics and I can open it up and find out whats wrong, but I'm tryin to ensure I haven't missed something in how it operates.

Looking at the wiring diagram now, There is a Door microswitch, a footbrake microswitch, so I have those both covered already. Sadly the wiring diagram is only for the single phase units, so mine will be slightly different. Looks like a 230/50-240/60 coil. Some of it is also in Italian. I'll have to open it up, but it does verify there are only 2 microswitches. It recommends a fused circuit, but there is no fuse it looks like.

[John Lifer]

First I would totally insure that you have a three phase machine. There is a single phase with same size motor on this s640p. If plate on motor says three phase it is.... You said you checked it was wired correctly, recheck that.
Otherwise, you might not have three phase machine. I would check and recheck the switch for the brake. Then potentially the estops. I'd see if control board has any lights on it to indicate power on.
I would look for loose or broken wire also since this machine was shipped recently. might be simple fix.

[Bill Dufour]

You will probably have to jumper the door switch to test the rest. It may not be electrically closing when the door is closed. no good way to test except possibly clipping leads on and hanging them out the door.
Does your meter make noise for continuity? If so clip leads to the door switch and close the door. If the switch is good you should hear the noise. Kind of like checking a car trunk light switch.
Bill D

[Cliff Polubinsky]

Derek,

My saw has the door switches, and it also has a switch on the blade tension release. If the blade isn't tensioned the motor won't start.

Try putting a blade on, tension it and see if it makes a difference.

Cliff

[Erik Loza]

There shouldn’t be any microswitch reated to blade tension on this machine. Derek, is the J-box in your photo that says “220V” OEM? Not something you added? I have literally never seen anything on any Euro machine that indicates 220V. Always 230V. Very odd if OEM. I wonder if they are doing that for the US market?

Erik