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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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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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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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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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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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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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(too) near Washington D.C. |
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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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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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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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Default Old Grob bandsaw.. no torque/ power

On Thu, 1 Aug 2019 13:33:43 -0700 (PDT), wrote:

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.



But oftentimes the bad cap is the culprit. I live on an island that is
mostly rural or semi-rural so we have lots of water wells. And nearly
every well has a single phase cap start motor that spins the pump. My
neighbor's well has a second pump that is used to pump and pressurize
the water for his house because it is quite uphill from the well head
and his well is already pretty deep. The motor refused to start and
did the typical humming till the breaker pops business. So I told my
neighbor to just go buy a start cap. Even though we are mostly rural
there is a naval base on the north end and a Home Depot. But nobody
had a start cap for his well. Not even the well pump installers. All
they could do was order the cap. So I took one out of my band saw
which got him water and he ordered two caps so he would have a spare.
Eric
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Default Old Grob bandsaw.. no torque/ power

wrote in message
...
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.


When a student asked if there was a troubleshooting procedure the
answer was yes, but since it covered every possibility it took far too
long to run through. They said they'd found that teaching students how
the circuits operated in detail resulted in much shorter downtimes of
the communications links we supported.

That worked for them as long as the Vietnam draft brought in science
and engineering grads with the aptitude and (more importantly) the
patience to learn complex systems. After it ended they had to
downgrade to board-swapping.




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