In article ,
wrote:
On Sun, 13 Apr 2014 08:48:45 -0400, Keith Nuttle
I have followed his recommendation ever since and the motor is still in
good conditions.

Wouldn't this solution be moot if he bought and used a TEFC motor?

Except for spending the $200-$300 for the new motor, I guess it would. If it
was me, I'd just continue cleaning the original every 3-5 years.


--
Often wrong, never in doubt.

Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

In article ,
wrote:
On Sun, 13 Apr 2014 08:38:25 -0500, dpb wrote:
Why spend several hundred $$ to save a minute or two of air blast once
in a while? Certainly the amount of use given the saw the power savings
isn't going to make up for it.

You could apply that sentiment to a whole lot of things. Cell phones,
computers, microwaves, televisions, etc. The question is, does someone
want the convenience of modern day technology or do they want to go
the older route.

In the end, it might make up for it if you consider all the time and
problems the OP appears to be having to get his machine up and running
again.


You may recall that in the original post, the problem was the SWITCH, not
the motor. So even he he bought the new motor, it wouldn't solve the
immediate problem the OP had.


--
Often wrong, never in doubt.

Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

In article om,
Lew Hodgett wrote:


Lew Hodgett wrote:

Although not $200, this solves your problem with today's
technology.


http://tinyurl.com/nw7ppyb
--------------------------------------------------------
Sorry for the omission.
Should have included:

http://tinyurl.com/od3xesa

------------------------------------------------------------
"woodchucker" wrote:

I think that is overkill... $80 for a switch..
A normal 20 amp wall switch will do.

----------------------------------------------
As long as you're willing to give up thermal overload protection
for the motor.

Lew



I would bet that the original motor has built-in thermal overload, just
as many (if not most) contractor saws have had for many many years.


--
Often wrong, never in doubt.

Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

Larry W wrote:
In article om,
Lew Hodgett wrote:


Lew Hodgett wrote:

Although not $200, this solves your problem with today's
technology.


http://tinyurl.com/nw7ppyb
--------------------------------------------------------
Sorry for the omission.
Should have included:

http://tinyurl.com/od3xesa

------------------------------------------------------------
"woodchucker" wrote:

I think that is overkill... $80 for a switch..
A normal 20 amp wall switch will do.

----------------------------------------------
As long as you're willing to give up thermal overload protection
for the motor.

Lew



I would bet that the original motor has built-in thermal overload,
just as many (if not most) contractor saws have had for many many
years.

Not to mention that the themal overload in the switch has no idea at all
what the motor is seeing.

--

-Mike-

"Mike Marlow" wrote:

Not to mention that the themal overload in the switch has no idea at
all what the motor is seeing.
--------------------------------------------------------
Sorry Charlie, only the best get to be StarKist.

The motor and overload are in series and see
exactly the same current.

BTW, at least 95% of all 3 phase motors are protected
by an overload relay that is art of the magnetic motor
starter used to control the motor.

Lew

Lew Hodgett wrote:
"Mike Marlow" wrote:

Not to mention that the themal overload in the switch has no idea at
all what the motor is seeing.
--------------------------------------------------------
Sorry Charlie, only the best get to be StarKist.

The motor and overload are in series and see
exactly the same current.

BTW, at least 95% of all 3 phase motors are protected
by an overload relay that is art of the magnetic motor
starter used to control the motor.


And heat is not only a result of overcurrent. Sorry Charley...

--

-Mike-

"Mike Marlow" wrote:
And heat is not only a result of overcurrent. Sorry Charley...
-------------------------------------------

???????

Lew

On Sun, 13 Apr 2014 18:21:15 -0700, "Lew Hodgett"
wrote:


"Mike Marlow" wrote:

Not to mention that the themal overload in the switch has no idea at
all what the motor is seeing.
--------------------------------------------------------
Sorry Charlie, only the best get to be StarKist.

Sorry Charlie, you're in the wrong ocean.

The motor and overload are in series and see
exactly the same current.

But NOT the same temperature. If it were a matter of current, motors
wouldn't have Klixons.

BTW, at least 95% of all 3 phase motors are protected
by an overload relay that is art of the magnetic motor
starter used to control the motor.

Irrelevant. All fractional-horse motors are protected with Klixons,
or similar.

On Sun, 13 Apr 2014 18:44:02 -0700, "Lew Hodgett"
wrote:

"Mike Marlow" wrote:
And heat is not only a result of overcurrent. Sorry Charley...
-------------------------------------------

???????

Reduced airflow, perhaps???????

On Sun, 13 Apr 2014 18:21:15 -0700, "Lew Hodgett"
wrote:


"Mike Marlow" wrote:

Not to mention that the themal overload in the switch has no idea at
all what the motor is seeing.
--------------------------------------------------------
Sorry Charlie, only the best get to be StarKist.

The motor and overload are in series and see
exactly the same current.

BTW, at least 95% of all 3 phase motors are protected
by an overload relay that is art of the magnetic motor
starter used to control the motor.

Lew


An overload relay and thermal protection are two different things -
and this is a single phase motor

On 4/13/2014 8:48 AM, Keith Nuttle wrote:
On 4/12/2014 9:28 PM, Lew Hodgett wrote:
You're dealing with a 40+ year old motor that as my mother would
say,
"doesn't owe me anything."

Jump in your handy-dandy go kart and go to the nearest Grainger and
buy a new motor.

You solve your problem SAFELY.

Lew
----------------------------------------------
"Keith Nuttle" wrote:

Even though it is a 40 year old motor it has been maintained. It is
not cost effective to replace the over $200 motor because the $30
switch failed. Do I see over 10 trillion dollars in 5 years
----------------------------------------------------
Lew Hodgett wrote:

How do you maintain a motor, wipe the sawdust off?

Although not $200, this solves your problem with today's technology.


http://tinyurl.com/nw7ppyb


Lew


"How do you maintain a motor, wipe the sawdust off?"
__________________________________________________ ____

The saw was purchased about 1970. I inherited the saw about 1987. My
father-in-law had been sick for a long time so the saw got used very
little.

At some time in the late 90's the motor died. I took it down to the
local small motor repair shop, for a diagnosis of whether I needed a new
motor. He looked at it ask a couple of question, and reached for a
screw drive. He proceeded to disassemble the motor and found a splinter
of wood in a contact in the motor start circuit. He took out the
armature and cleaned the old saw dust out of the motor. With each step
he showed me exactly what he was doing. He recommended doing that
every 3 to 5 years depending on the usage, and to vacuum the vents on
the motor with every use.

I have followed his recommendation ever since and the motor is still in
good conditions.

So much to be said for almost anything made 40 years ago in the US. You
could take them apart and fix them. The trend is toward lowest cost and
minimum amount of materials. Not so fixable. I tried to fix a motor
start on a Sears washing machine not long ago. Not only was that not
possible but the part was over $60 (not retail), on a used washer worth
$80 used, not a good plan.

As I said in the previous post, after not finding what I wanted for a
replacement, I took the switch apart and rebuilt it. I will order a
new switch on line. That is what I did for my ShopVac after that
switch failed.

Seems like the right plan. I thought the switch was no longer available.

Sears parts departments used to be quite good, and relatively cheap. I
believe much of that has gone by the wayside.




--
pentapus

As I said in the previous post, after not finding what I wanted for a
replacement, I took the switch apart and rebuilt it. I will order a
new switch on line. That is what I did for my ShopVac after that
switch failed.

Seems like the right plan. I thought the switch was no longer available.

Sears parts departments used to be quite good, and relatively cheap. I
believe much of that has gone by the wayside.



The switch assembly. Switch, box, cord, and plug and cover.

I am sure some where there is a replacement switch, that will fit in the
box.

pentapus wrote:
On 4/13/2014 8:48 AM, Keith Nuttle wrote:
On 4/12/2014 9:28 PM, Lew Hodgett wrote:
You're dealing with a 40+ year old motor that as my mother would
say,
"doesn't owe me anything."

Jump in your handy-dandy go kart and go to the nearest Grainger
and buy a new motor.

You solve your problem SAFELY.

Lew
----------------------------------------------
"Keith Nuttle" wrote:

Even though it is a 40 year old motor it has been maintained. It
is not cost effective to replace the over $200 motor because the
$30 switch failed. Do I see over 10 trillion dollars in 5 years
----------------------------------------------------
Lew Hodgett wrote:

How do you maintain a motor, wipe the sawdust off?

Although not $200, this solves your problem with today's technology.


http://tinyurl.com/nw7ppyb


Lew


"How do you maintain a motor, wipe the sawdust off?"
__________________________________________________ ____

The saw was purchased about 1970. I inherited the saw about 1987. My
father-in-law had been sick for a long time so the saw got used
very little.

At some time in the late 90's the motor died. I took it down to the
local small motor repair shop, for a diagnosis of whether I needed a
new motor. He looked at it ask a couple of question, and reached
for a screw drive. He proceeded to disassemble the motor and found
a splinter of wood in a contact in the motor start circuit. He
took out the armature and cleaned the old saw dust out of the motor.
With each step he showed me exactly what he was doing. He
recommended doing that every 3 to 5 years depending on the usage,
and to vacuum the vents on the motor with every use.

I have followed his recommendation ever since and the motor is still
in good conditions.

So much to be said for almost anything made 40 years ago in the US.
You could take them apart and fix them. The trend is toward lowest
cost and minimum amount of materials. Not so fixable. I tried to fix
a motor start on a Sears washing machine not long ago. Not only was
that not possible but the part was over $60 (not retail), on a used
washer worth $80 used, not a good plan.

As I said in the previous post, after not finding what I wanted for a
replacement, I took the switch apart and rebuilt it. I will order a
new switch on line. That is what I did for my ShopVac after that
switch failed.

Seems like the right plan. I thought the switch was no longer
available.
Sears parts departments used to be quite good, and relatively cheap. I
believe much of that has gone by the wayside.

I would recommend a paddle switch as long as a replacement is in order.
Grizzly has the best prices I've found on them. The paddle makes for a very
convenient way to shut off the saw - I have mine mounted so I can kick it
off with my knee. So much better than reaching for a switch after a cut.

--

-Mike-

In article ,
Mike Marlow wrote:
...snipped...
Not to mention that the themal overload in the switch has no idea at all
what the motor is seeing.


Not necessarily true either. I didn't look in detail at theat switch's
specifications, but I believe it had current-sensing heaters in it
matched to the motor size, similar to what a magnetic starter with overload
protection uses.


--
There is always an easy solution to every human problem -- neat,
plausible, and wrong." (H L Mencken)

Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On Tue, 15 Apr 2014 00:38:06 +0000 (UTC),
(Larry W) wrote:

In article ,
Mike Marlow wrote:
...snipped...
Not to mention that the themal overload in the switch has no idea at all
what the motor is seeing.


Not necessarily true either. I didn't look in detail at theat switch's
specifications, but I believe it had current-sensing heaters in it
matched to the motor size, similar to what a magnetic starter with overload
protection uses.
Which will PREDICT temperature based on load, but cannot take into
consideration reduced air flow and other factors.

On Mon, 14 Apr 2014 19:34:22 -0400, pentapus
wrote:



Sears parts departments used to be quite good, and relatively cheap. I
believe much of that has gone by the wayside.


Like most of what used to be good about sears

On 4/14/2014 10:31 PM, wrote:
On Tue, 15 Apr 2014 00:38:06 +0000 (UTC),
(Larry W) wrote:

In ,
Mike wrote:
...snipped...
Not to mention that the themal overload in the switch has no idea at all
what the motor is seeing.


Not necessarily true either. I didn't look in detail at theat switch's
specifications, but I believe it had current-sensing heaters in it
matched to the motor size, similar to what a magnetic starter with overload
protection uses.
Which will PREDICT temperature based on load, but cannot take into
consideration reduced air flow and other factors.

It has nothing whatever really to do with predicting the motor
temperature, per se, it's simply overcurrent motor protection (as
opposed to overcurrent _circuit_ protection that is the function of the
breaker/fuse). Sizing is based on FLA and motor rating of how long is
allowed before protection kicks in.

The devices have colloquially been called "heaters" at least in the US
(I don't know about the frozen north jargon ) as they're just thermal
links. Some are resettable bimetal strips (the builtin motor variety
for example) whereas typical magnetic starter heaters are fusible links.

http://www.ab.com/en/epub/catalogs/12768/229240/229248/10521726/10551021/10551660/Introduction.html

--

On 4/15/2014 9:22 AM, dpb wrote:
....

It has nothing whatever really to do with predicting the motor
temperature, per se, ...

That is, yes, the motor ratings are generally based on what the internal
insulation and all will stand as temperature overloads but that is
protected against by the current draw and manufacturers' ratings with
the presumption of proper installation, cooling, maintenance including
removal/prevention of dust buildup, etc., etc, etc., ... so that by
limiting the current draw within the expected time the internal
temperatures will not reach danger levels.

--

On 4/13/14 9:55 AM, wrote:
On Sat, 12 Apr 2014 23:10:14 -0400, pentapus
wrote:

On 4/11/2014 8:57 PM, Keith Nuttle wrote:
I have a Sears 10 inch table saw with 1hp motor that was purchased in
1970. The motor is a capacitor start type motor 115 volts 60 cycles
3450 RPM. The motor uses 20 amps. A 15 amp circuit will not run the
motor. I assume the starting circuit requires the 20 amps, and the run
condition is 15 amps.

The saw came with a two outlet switch that the motor plugged into.

The saw is used for cross cutting of 1 X 2 or 1 X 4 pine or fir. It
never runs for more the 10 minutes at a time. (pictures stretchers and
frames )

Now my question. The switch itself died to night, I have a project that
I on which I am running out of time, I plan to try to find a
replacement switch tomorrow.

That failing can I can I use a common 6 outlet power strip as a switch
on this motor?

Two things...

1)

An inductive load has a turn on/ turn off voltage spike. That will be
harsh on the relatively wimpy switches they put in switched outlets.

Agreed. The saw will be drawing far more than 20A when it starts, not
to mention the arcing caused by the inductive load. I'd buy a switch
that was rated for motors.

I've used the 'motor rated' switches that look like a typical wall light
switch for an old 3/4 HP table saw. These have the red/black body and
are reasonably cheap.
They don't last forever though (I've eaten up 2 over the years with
light use)
-Bruce


2)

If it is a 20A only saw, the plug will have one of the pins horizontal,
rather than vertical and won't fit.

It's a 1HP saw, so about 10A. It draws far more than that when
starting, so the 20A circuit. It likely has a NEMA 5-15 plug.
So...

I think they have covers for handy boxes that will fit a switch and an
outlet. Buy a good light switch and use one of those.

Perhaps:

http://www.homedepot.com/p/Leviton-2...-2WS/202035005


If I can are there any limitations or problems that I should be aware of.


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