Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Old July 31st 19, 06:29 PM posted to rec.crafts.metalworking
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Default Old Grob bandsaw.. no torque/ power

Hi all, our old bandsaw stopped working so well. It has no torque/ power
and when you turn on the unloaded motor it sometimes runs backwards.

The thought here is that maybe a start or run capacitor had gone bad...
but we are all mostly clueless when it comes to motors. Any ideas
before I try and get the motor out.

George H.

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Old July 31st 19, 06:35 PM posted to rec.crafts.metalworking
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Default Old Grob bandsaw.. no torque/ power

On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4, wrote:
Hi all, our old bandsaw stopped working so well. It has no torque/ power
and when you turn on the unloaded motor it sometimes runs backwards.

The thought here is that maybe a start or run capacitor had gone bad...
but we are all mostly clueless when it comes to motors. Any ideas
before I try and get the motor out.

(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.


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Old July 31st 19, 06:55 PM posted to rec.crafts.metalworking
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Default Old Grob bandsaw.. no torque/ power

On Wednesday, July 31, 2019 at 12:35:28 PM UTC-4, wrote:
On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4, wrote:
Hi all, our old bandsaw stopped working so well. It has no torque/ power
and when you turn on the unloaded motor it sometimes runs backwards.

The thought here is that maybe a start or run capacitor had gone bad...
but we are all mostly clueless when it comes to motors. Any ideas
before I try and get the motor out.

(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.


Never mind. problem fixed. (Sometimes all I need is a smart audience.)

GH
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Old July 31st 19, 08:39 PM posted to rec.crafts.metalworking
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Posts: 1,354
Default Old Grob bandsaw.. no torque/ power




wrote:
Hi all, our old bandsaw stopped working so well. It has no torque/
power and when you turn on the unloaded motor it sometimes runs
backwards.

The thought here is that maybe a start or run capacitor had gone bad...
but we are all mostly clueless when it comes to motors. Any ideas
before I try and get the motor out.

(Oh dear.. I think it's a three phase motor... (no cap))

Ah, well, the running backwards strongly indicates it is running on
single phase. Check the power switch/motor starter to make sure all 3
phases are connecting. Check any fuses. Look for loose/broken wires.
Without knowing what sort of switch/motor starter it has, I can't get
more detailed. It COULD be the motor, but could as likely be something
external.

Jon
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Old July 31st 19, 09:45 PM posted to rec.crafts.metalworking
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Default Old Grob bandsaw.. no torque/ power

wrote in message
...
On Wednesday, July 31, 2019 at 12:35:28 PM UTC-4,
wrote:
On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4,
wrote:
Hi all, our old bandsaw stopped working so well. It has no
torque/ power
and when you turn on the unloaded motor it sometimes runs
backwards.

The thought here is that maybe a start or run capacitor had gone
bad...
but we are all mostly clueless when it comes to motors. Any
ideas
before I try and get the motor out.

(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.


Never mind. problem fixed. (Sometimes all I need is a smart
audience.)

GH


You told us the symptoms, so what was the cause?

We all started out clueless and had to learn somehow.




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Old August 1st 19, 04:47 AM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Jul 2010
Posts: 2,575
Default Old Grob bandsaw.. no torque/ power

On 2019-07-31, wrote:
Hi all, our old bandsaw stopped working so well. It has no torque/ power
and when you turn on the unloaded motor it sometimes runs backwards.

The thought here is that maybe a start or run capacitor had gone bad...
but we are all mostly clueless when it comes to motors. Any ideas
before I try and get the motor out.

George H.


Certainly the start capacitor. I don't know whether that one
has a run cap at all, but starting sometimes backwards says that it is
the start cap.

Any clue as to which model? There seem to be a number of
models.

I downloaded the manuals for the 4V, and it shows as having a
3-phase motor, so no start cap.

But if it is a single-phase motor, it should have a start cap,
and it will likely be under a bulge cover screwed to the side of the
motor. Unscrew the cover (with the saw disconnected from power) and
pull the quick-disconnect (push-on) connectors from the cap, unscrew the
clamp which holds it, and pull it out. Read the voltage and capacitance
(uF) from what is printed on the cap, and go to a motor place to
purchase an equivalent. When you put the new one in -- just make sure
that one push-on goes to one terminal and the other to the other.
(Likely there are two or three push-on tabs for each terminal, and if
you push both onto the same terminal you will probably stall the motor.
Which wire goes to which terminal should not matter, as this is an AC
application, not DC -- which electrolytic capacitors do care about.)

Good Luck,
DoN.

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Old August 1st 19, 07:56 PM posted to rec.crafts.metalworking
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Posts: 241
Default Old Grob bandsaw.. no torque/ power

On Wednesday, July 31, 2019 at 3:44:32 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Wednesday, July 31, 2019 at 12:35:28 PM UTC-4,
wrote:
On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4,
wrote:
Hi all, our old bandsaw stopped working so well. It has no
torque/ power
and when you turn on the unloaded motor it sometimes runs
backwards.

The thought here is that maybe a start or run capacitor had gone
bad...
but we are all mostly clueless when it comes to motors. Any
ideas
before I try and get the motor out.
(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.


Never mind. problem fixed. (Sometimes all I need is a smart
audience.)

GH


You told us the symptoms, so what was the cause?

We all started out clueless and had to learn somehow.


Oh sorry, one (or two) of the phases was missing. Someone
had been abusing the power plug into the wall outlet...
Five minutes with a screwdriver and all was good.

George H.
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Old August 1st 19, 09:08 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Jun 2011
Posts: 5,499
Default Old Grob bandsaw.. no torque/ power

wrote in message
...
On Wednesday, July 31, 2019 at 3:44:32 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Wednesday, July 31, 2019 at 12:35:28 PM UTC-4,

wrote:
On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4,

wrote:
Hi all, our old bandsaw stopped working so well. It has no
torque/ power
and when you turn on the unloaded motor it sometimes runs
backwards.

The thought here is that maybe a start or run capacitor had
gone
bad...
but we are all mostly clueless when it comes to motors. Any
ideas
before I try and get the motor out.
(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.

Never mind. problem fixed. (Sometimes all I need is a smart
audience.)

GH


You told us the symptoms, so what was the cause?

We all started out clueless and had to learn somehow.


Oh sorry, one (or two) of the phases was missing. Someone
had been abusing the power plug into the wall outlet...
Five minutes with a screwdriver and all was good.

George H.


I've been troubleshooting electronics since 1970. It's rare for the
problem to be other than a bad connection.

At the Fort Monmouth Army school the instructors heated and removed an
end cap from glass tube fuses and inserted too-short heavy bus wire or
paper tags with "good fuse" on them, to teach us to check the power
first, and test fuses with an ohmmeter.




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Old August 1st 19, 10:33 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Nov 2008
Posts: 241
Default Old Grob bandsaw.. no torque/ power

On Thursday, August 1, 2019 at 3:07:38 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Wednesday, July 31, 2019 at 3:44:32 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Wednesday, July 31, 2019 at 12:35:28 PM UTC-4,

wrote:
On Wednesday, July 31, 2019 at 12:29:28 PM UTC-4,

wrote:
Hi all, our old bandsaw stopped working so well. It has no
torque/ power
and when you turn on the unloaded motor it sometimes runs
backwards.

The thought here is that maybe a start or run capacitor had
gone
bad...
but we are all mostly clueless when it comes to motors. Any
ideas
before I try and get the motor out.
(Oh dear.. I think it's a three phase motor... (no cap))

Maybe check the three voltages?
Or a bad motor

George H.

Never mind. problem fixed. (Sometimes all I need is a smart
audience.)

GH

You told us the symptoms, so what was the cause?

We all started out clueless and had to learn somehow.


Oh sorry, one (or two) of the phases was missing. Someone
had been abusing the power plug into the wall outlet...
Five minutes with a screwdriver and all was good.

George H.


I've been troubleshooting electronics since 1970. It's rare for the
problem to be other than a bad connection.

Grin... Well someone else here found the problem and 'assumed' a bad cap.
after a day I was brought it to help... I sorta bought into to the 'bad cap'
idea.

At the Fort Monmouth Army school the instructors heated and removed an
end cap from glass tube fuses and inserted too-short heavy bus wire or
paper tags with "good fuse" on them, to teach us to check the power
first, and test fuses with an ohmmeter.


I've been thinking of some sort of trouble shooting guide for people.
It seems like a common mistake is assuming the problem is the first thing
you think of. And then you follow that idea down some rabbit hole.
The first thing to do when trouble shooting is to think of all the
things it could be. Make a list if you have to. Then start by checking all the
simple things on the list. (simple as in simple to test.)
Hmm, well and get lots of data on the problem, that's important. I do trouble
shooting on the phone/ email every week or two... you learn to ask a lot of
questions.

George H.






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