15" Wide Belt Sander won't turn off

[Bill Dufour]

I am not sure how the e-brake works. It may be spring loaded on and needs power to pull the brake off so things can turn. Or it could take power to apply the brake and no power to the brake circuit means no brakes.
Spring loaded apply would be the safest method.
Looking at the first diagram it looks like you have to push in a button to engage the e-brake. As soon as the e-brake button is released the e-brake is also released.
Does pushing in the e-brake button make the contactor move?
Bill D

[Stan Coryell]

The single line does not show any electromechanical brake. At least not that I can see.
I suspect the circled M3 is the actual E stop switch and that switch is used to turn the main contactor (M3) off and on. The E stop either breaks 6 and 7. or 5.
The last set of instructions will tell us if it's 5.
Once we have common (red 2) to M3 contactor and possibly M1 and M2, we will work at the 120 volt (red 3).

[Josh Falcon]

Thanks again guys. Unfortunately didn’t have time to get out to the shop today but I’ll have a few hours tomorrow, will update everyone then.

Thanks
Josh

[Josh Falcon]

Hi All

Stan, here's what I got based on your instructions

"Measure voltage between 110 and Red 2 at the two motor contactors. It should read 120 volts" I got 113V between 110V on transformer and red 2 wire on each contactor. Got the same reading on the terminal to the left of 2 wire (circled in blue below)

contactors3 by Josh Falcon, on Flickr

"Check red 5 to 110 (on the "emergency brake contactor"). It should read 120 volts. Push the E stop in and you should lose 120 volts between red 5 and 110." I get 113V between 110V on transformer and red 5. I then engaged the E stops one at a time (2 pushbutton and the E bar in front of the conveyor, still got 113V between 110V and red 5.

[Stan Coryell]

So far:
The transformer works
All three contactors have common.
The overloads aren't triped.

[Stan Coryell]

So far:
The transformer works
All three contactors have common.
The overloads aren't triped.

Land 3 back on 110 (low side of transformer )
Measure between 0 (low side of transformer) and (on the terminal strip)
6
8
10
Also measure between 0 and (at the contactors)
Red 8
Red 10
If you measure 120v on all, try to start it, stop and report back.
If you measure 0v, trace the wires from the close coil (red 5 and the other one buried in the upper right back) on the "emergency brake " contactor. Stop report back
I suspect they go to "sol" I'm not sure what that is.
I think the emergency brake contactor (M3) has to close for the M1 and M2 to function. But there might be order of operation. That's why there's a NC auxiliary on M3.
More than likely the "panic bar" or relay associated with it are the culprit.
Do the pneumatics have any electrical components ?
I think you have the wiring back to factory.
The single line isn't right. At least it's missing something.

[Bill Dufour]

I guess "SOL" is a solenoid to shift he brake lever on/off?
Bil lD

[Stan Coryell]

My guess is "sol" is a latching relay that breaks red 5 and red 3 when the "panic bar" is pushed.
Is there an electromechanical break ?
Either way, I think M3 needs to be closed to get M1 and M2 to function.

[Josh Falcon]

So thought we had a breakthrough just now, but one step forward, one step back.

I connected Red 3 wire to 110V on the bottom of the transformer. I cut power on to the machine and heard a contactor click, I had left the front E stop engaged from the night prior, so it seemed like I had power to the panel. I measured from 0V to 6, 8 and 10 on the terminal strip, 110V to all three. Same from 0V to 8 and 10 on the contactors. I made sure all the E stops were clear and tried starting the machine and nothing.

I went back and tried to find what happened and noticed Fuse 1 blew. The machine will still turn on by manually engaging the contacts but I no longer have 240v to the top of transformer or anything after.

I have a few pics of the braking system (pneumatic actuated) and the various limit switches at the head and "panic bar" that I'll upload when I have a few min tonight. I've ordered some more fuses in the meantime based on what was in there previously (Bussman ACG-6 Fast Acting).

[Stan Coryell]

You haven't taken any steps backwards.
120 volts at 6, 8, and 10 tells us: you have power at the
E stop, M1 stop, and M2 stop.
I seems the fuse blew when you pressed one of the two start buttons. Next step:
1 power off
2 replace fuse (it should be 1 amp not 6) you can leave the 6s for now
3 lift red 9 and red 11 off M1 and M2
4 restore main power
5 clear 1 E stop at a time checking power at 110/0, stop if you lose 120 volt and report back.
6 press start 1 (nothing will happen) check power at 110/0. If fuse blows, replace
7 press start 2 and follow same procedure as start 1

With red 9 and red 11 lifted, we are able to check for shorts between the start buttons and the contactor, excluding the contactor. If pressing one of the start buttons blew a fuse, trace 9 or 11 back to the start buttons. Look for a pinched wire, landed wrong, ect.
If fuses did not blow: land red 9 on M1 and press start 1, check 110 to zero, repeat for red 11 and M2

Note: It's possible it took a few minutes for the fuse to blow and it has nothing to do with you pressing buttons.
I would: trip all E Stops, replace fuse, restore main power, add wait about 10 minutes. Check power at 110/0. If you have 120 volts proceed with the steps above.

Trip means to set so the machine won't run
Clear means to set so the machine runs

I would not keep pushing those contactors in manually. I won't tell you anything a meter can't. You also run the risk of damaging something.

[Josh Falcon]

Thanks Stan. The fuses should be here tomorrow so I'll reinstall and run through the sequence you outlined.

In the meantime here are some photos of the various limit switches and the motor brake, for reference, if necessary. One thing I forgot to mention was that the air line from the solenoid to the brake was completely gone when I got the machine. I replaced it before we started trouble shooting the electricals.

Panic bar switch




Belt limit switch (2X)


Belt limit wiring


Motor brake

[Erik Loza]

Josh, FYI that you appear to be missing a V-belt. Maybe you caught that already. Or does the upper pulley only take one? Every WB I have experience with has two, if not three belts. Looking good, by the way.

Erik

[Bill Dufour]

I am surprised the panic bar switch is "normally open" In my experience stop switches should be normally closed for safety sakes. the way that is wired if the wires go bad the switch has no way to turn off the power.
Bill D

[Bert McMahan]

If a contactor blew in the open position and he didn't have spares he might've just said screw it, I need it running now not 3 days from now and jumped over the contactors.

[Josh Falcon]

If a contactor blew in the open position and he didn't have spares he might've just said screw it, I need it running now not 3 days from now and jumped over the contactors.

There was a lot of "screw it" going on in this place. I'm certain whatever the proper repair was was more $$ than the "grip it and rip it" approach, hence where we are now.

Josh, FYI that you appear to be missing a V-belt. Maybe you caught that already. Or does the upper pulley only take one? Every WB I have experience with has two, if not three belts. Looking good, by the way.

Erik

Yeah, I have a replacement I just havent gotten around to putting it on. I hadn't planned to run it under load until I got all the electrical stuff sorted. I'm actually wondering if it broke at some point and thats what decapitated the brake air line.

I am surprised the panic bar switch is "normally open" In my experience stop switches should be normally closed for safety sakes. the way that is wired if the wires go bad the switch has no way to turn off the power.
Bill D

Totally possible the switch has also been messed with at some point, I might even put money on it. Stan has been a HUGE help so far so hopefully we can track down the issue.