Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a 1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor, belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker trips.
When it trips, I can just reset the breaker, then turn on the saw and it will
always start the second time. If I shut it off, the next time I try to turn it
on (warm or cold), it will almost always trip the breaker.

I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a 20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain somewhat
portable.

Thanx.

Don

"Don97623" wrote in message
...
Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a
1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor,
belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker
trips.
When it trips, I can just reset the breaker, then turn on the saw and it
will
always start the second time. If I shut it off, the next time I try to
turn it
on (warm or cold), it will almost always trip the breaker.

I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a
20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain
somewhat
portable.

Thanx.

Don

You should not have any problems running this motor on a proper 20 amp
circuit.
Sounds like a bad start winding switch to me. Most single phase motors have
a centrifical switch that energizes the start windings for a second when you
turn on the motor. The switch contacts get dirty over time and fail to make
good contact.
If your are comfortable doing it you may be able to take the motor apart and
clean the contacts with some fine emery paper.
If it is an open motor you could just try to blow it out well with
compressed air, it is possible that some dust is hanging up the start switch
too.
Also it is possible you have a bad connection some where too.
Greg

On 29 Nov 2004 04:04:19 GMT, (Don97623) wrote:

However, just about 50% of the time I turn it on, the circuit breaker trips.

I've no idea about US electrics....

But here in the UK we have circuit breakers that are either "Class B"
or "Class C". B is the usual domestic sort, C is a little
slower-acting (although the same current rating). if you have big
motors or welders, you need a class C to avoid this nuisance tripping.

--
Smert' spamionam

This may be totally off the mark, but here goes. I had a similar problem
with a small 120 volt planer. After looking at every possible problem, I
found that the plug was just barely engaged in the receptical. Pushed plug
in and problem solved.
Dave

"Andy Dingley" wrote in message
...
On 29 Nov 2004 04:04:19 GMT, (Don97623) wrote:

However, just about 50% of the time I turn it on, the circuit breaker
trips.

I've no idea about US electrics....

But here in the UK we have circuit breakers that are either "Class B"
or "Class C". B is the usual domestic sort, C is a little
slower-acting (although the same current rating). if you have big
motors or welders, you need a class C to avoid this nuisance tripping.

--
Smert' spamionam

You may also need to replace the breaker. I have found that once a
breaker goes a half dozen times, it becomes much more load sensitive.
Your breaker may be worn out. They are usually easy to replace -- just
pop in a new one.

Lars



On 2004-11-28 22:04:19 -0600, (Don97623) said:

Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a 1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor, belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker
trips. When it trips, I can just reset the breaker, then turn on the
saw and it will
always start the second time. If I shut it off, the next time I try to turn it
on (warm or cold), it will almost always trip the breaker.
I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a 20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain somewhat
portable.

Thanx.

Don

If you are using an extension cord, try using a shorter one, one with
thicker guage wire, or if possible, plugging the tool directly into the
wall socket. Worked wonders for me just last week.

-John

On Mon, 29 Nov 2004 08:55:52 -0600, Lars S
wrote:

You may also need to replace the breaker. I have found that once a
breaker goes a half dozen times, it becomes much more load sensitive.
Your breaker may be worn out. They are usually easy to replace -- just
pop in a new one.

Lars

VERY true!
I bought a "super duper" 12 gauge cord with triple outlet and a 15 amp
breaker on the plug for yard work and stuff... worked great until I
used it for my compressor one weekend, and after the compressor popped
the breaker a few times, even the leaf blower started popping it...
had to chop the plug off and put a "normal" one on..

This has a 15' long, 12-gauge cord on it, so I don't really think that's it.

I pulled the back of the motor off tonight, and located the centrifugal switch
arrangement for the capacitor. My take on how this works is:
When the motor is off, the centrifugal "clutch" presses against the switch,
closing the 2 contacts, which feed the capacitor.
When the saw spins up, the clutch pulls back, opening the contacts and taking
the capacitor out of the circuit.

I cleaned the contacts and pulled the contacts up slightly to make better
contact, but when I reassembled and tried to start it (no belt attached), it
immediately popped the breaker. Next try it spun up ok, and I did get several
starts, but it still pops the breaker often (though maybe not quite as often as
it did before.) Maybe another, better cleaning is in order. I'm not sure how
to check out the capacitor, but that could be a problem. I'll also see if I
can verify continuity through the switch when everything's assembled (has to be
assembled for switch contact to be made.)

I definitely hear the "clutch" plate snap back into normal mode and rub against
the switch contacts once the motor slows down, so the mechanical part seems to
be working ok.

Any other thoughts?
If another round of playing doesn't work, I'll find a local motor rebuilder &
see if they can fix it reasonably cheaply.

Thanx,
Don

If you are using an extension cord, try using a shorter one, one with
thicker guage wire, or if possible, plugging the tool directly into the
wall socket. Worked wonders for me just last week.

-John

Thanks for all the other suggestions - I didn't see them from the AOL
newsreader - just saw them after looking at the thread through Google.

As far as the circuit breaker & receptacles go, the problem started on an old
15 amp circuit, but it's now on a brand new 20 amp breaker and all new wiring,
so I doubt that's it - not that I couldn't have gotten a bad breaker, of
course. I'll also check all my connections in the motor & switch. Does anyone
know where to get a wiring diagram for a Rockwell motor? I think the diagram
which is usually inside the cover plate was either missing or illegible. When
I got the saw, the person I bought it from had disassembled it in order to get
it in the car, but had taped up the wires so it was pretty obvious how it
should be hooked up, but it's possible I got a wire or two in the wrong place.

Don

On Sun 28 Nov 2004 10:04:19p, (Don97623) wrote in
:

However, just about 50% of the time I turn it on, the circuit breaker
trips. When it trips, I can just reset the breaker, then turn on the
saw and it will always start the second time. If I shut it off, the
next time I try to turn it on (warm or cold), it will almost always
trip the breaker.

I originally had it plugged into a 15A circuit, and figured the
starting current was just a little high.
I had been meaning to add a power circuit to the basement, so I added
a 20A circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for
these machines, or what?

My Grizzly pops the breaker something like one time in ten at powerup. I
don't think my motor or yours is bad.

I'm leaning towards getting a slow-blow breaker. If I remember those
electric motor classes right, it's not unusual for an induction motor to
pull a lot of amps at the start, then drop. You need quite a bit of power
to get all that weight moving.

"Don97623" writes:

snip
Next try it spun up ok, and I did get several
starts, but it still pops the breaker often (though maybe not quite as
often as
it did before.)

Sounds like you may have a defective cap.

Try the following:

1) Remove cap.
2) Spin rotor and apply power.

If motor comes up to speed without tripping c'bkr, replace starting
capacitor.

Good luck.

BTW, a 1P-20A is quite suitable with a #12 wire.

HTH

Lew

A. Replace the breaker. This one may just be a little "too" sensitive"
B. Attach the saw to a 20 amp circuit. You're cutting it a little close.
C. Rewire for 220 volt. End of problems.

bob g.

Don97623 wrote:
Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a 1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor, belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker trips.
When it trips, I can just reset the breaker, then turn on the saw and it will
always start the second time. If I shut it off, the next time I try to turn it
on (warm or cold), it will almost always trip the breaker.

I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a 20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain somewhat
portable.

Thanx.

Don

On Tue, 30 Nov 2004 04:10:19 GMT, Dan wrote:

On Sun 28 Nov 2004 10:04:19p, (Don97623) wrote in
:

However, just about 50% of the time I turn it on, the circuit breaker
trips. When it trips, I can just reset the breaker, then turn on the
saw and it will always start the second time. If I shut it off, the
next time I try to turn it on (warm or cold), it will almost always
trip the breaker.

I originally had it plugged into a 15A circuit, and figured the
starting current was just a little high.
I had been meaning to add a power circuit to the basement, so I added
a 20A circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for
these machines, or what?

My Grizzly pops the breaker something like one time in ten at powerup. I
don't think my motor or yours is bad.

I'm leaning towards getting a slow-blow breaker. If I remember those
electric motor classes right, it's not unusual for an induction motor to
pull a lot of amps at the start, then drop. You need quite a bit of power
to get all that weight moving.

what we used to do in the "old daze" was make up a box to plug the saw
into that had a light bulb socket in the circuit with a "slow blow"
fuse the same amperage as the breaker or main fuse.. seemed to help in
most cases..

On Tue, 30 Nov 2004 09:41:15 -0600, Robert Galloway
wrote:

A. Replace the breaker. This one may just be a little "too" sensitive"

IIRC you can get slow blowing breakers for applications like this. We
had to get one installed in our service panel when the pool pump motor
decided it wanted to trip the breaker every time it came out.

Check with an electrical supply house.

--RC

B. Attach the saw to a 20 amp circuit. You're cutting it a little close.
C. Rewire for 220 volt. End of problems.

bob g.

Don97623 wrote:
Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a 1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor, belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker trips.
When it trips, I can just reset the breaker, then turn on the saw and it will
always start the second time. If I shut it off, the next time I try to turn it
on (warm or cold), it will almost always trip the breaker.

I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a 20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain somewhat
portable.

Thanx.

Don

Sleep? Isn't that a totally inadequate substitute for caffine?

On 29 Nov 2004 04:04:19 GMT, (Don97623) wrote:

Hi

I've got a Rockwell Contractors saw which I recently bought. It's got a 1.5HP,
15A (@115V) original motor on it. The saw has seen a fair amount of use.

There doesn't seem to be any significant drag on the system, the motor, belt &
spindle seem to turn fine.

However, just about 50% of the time I turn it on, the circuit breaker trips.
When it trips, I can just reset the breaker, then turn on the saw and it will
always start the second time. If I shut it off, the next time I try to turn it
on (warm or cold), it will almost always trip the breaker.

Funny thing about breakers is that while they look like little
switches, they don't tend to work like them. I've found that once you
trip one once, you may as well just replace the sucker, because it's
going to trip again with less provocation and greater frequency as
time goes on. Could be there's nothing wrong with your saw, it might
just be a touchy breaker- is your saw the only thing plugged into that
circut, or did you genuinely overload it the first time by running too
many things at once?



I originally had it plugged into a 15A circuit, and figured the starting
current was just a little high.
I had been meaning to add a power circuit to the basement, so I added a 20A
circuit, and still have the same problem.

Does this mean the motor is bad, or are there soft-start options for these
machines, or what?

I could probably wire it up for 230V, but I'd like to have it remain somewhat
portable.

Thanx.

Don

Aut inveniam viam aut faciam