I found a motor at the dump. It works great and appears to even have
been part of a woodshop at one point (covered with sawdust). What I'm
not sure of is if it fits the requirements Gingery lays down.

The frame is a little larger than NEMA 48, but that's not a big deal.
Gingery also says it should be "split phase", which from my research
seems to mean that it has an extra circuit in when it spins up to give
it extra torque for a fast (or just strong?) start. The plate on this
one has a box labeled "Phase" and in the box is the value "1". So
that's a single-phase motor then? If so, does that rule this one out,
even considering it's a 1/2 HP instead of the 1/4 Gingery lists as minimum?

If that "Phase" box is unrelated to the split-phasedness, how can I tell
if this is a split-phase?

Single phase just means is runs on normal household current, nothing more. A
split phase motor doesn't have any capacitors on it, a cap-start has one, a cap
start/run motor has two.

Split phase motors are actually the weakest and slowest of the three. Less
starting torque than the other two. I have no clue why Gingery would recommend
one, other than for cost reasons. Maybe the design isn't strong enough for the
fast start a cap start motor would have. You can use any kind of motor you want
on a lathe.

GTO(John)

I found a motor at the dump. It works great and appears to even have
been part of a woodshop at one point (covered with sawdust). What I'm
not sure of is if it fits the requirements Gingery lays down.

The frame is a little larger than NEMA 48, but that's not a big deal.
Gingery also says it should be "split phase", which from my research
seems to mean that it has an extra circuit in when it spins up to give
it extra torque for a fast (or just strong?) start. The plate on this
one has a box labeled "Phase" and in the box is the value "1". So
that's a single-phase motor then? If so, does that rule this one out,
even considering it's a 1/2 HP instead of the 1/4 Gingery lists as minimum?

If that "Phase" box is unrelated to the split-phasedness, how can I tell
if this is a split-phase?

Well, I don't know a thing about motors. This one has a big cylindrical
thing mounted on top of it (parallel to the shaft). Is that a
capacitor? (I could post a picture if someone wants to see it.)

GTO69RA4 wrote:
Single phase just means is runs on normal household current, nothing more. A
split phase motor doesn't have any capacitors on it, a cap-start has one, a cap
start/run motor has two.

Split phase motors are actually the weakest and slowest of the three. Less
starting torque than the other two. I have no clue why Gingery would recommend
one, other than for cost reasons. Maybe the design isn't strong enough for the
fast start a cap start motor would have. You can use any kind of motor you want
on a lathe.

GTO(John)


I found a motor at the dump. It works great and appears to even have
been part of a woodshop at one point (covered with sawdust). What I'm
not sure of is if it fits the requirements Gingery lays down.

The frame is a little larger than NEMA 48, but that's not a big deal.
Gingery also says it should be "split phase", which from my research
seems to mean that it has an extra circuit in when it spins up to give
it extra torque for a fast (or just strong?) start. The plate on this
one has a box labeled "Phase" and in the box is the value "1". So
that's a single-phase motor then? If so, does that rule this one out,
even considering it's a 1/2 HP instead of the 1/4 Gingery lists as minimum?

If that "Phase" box is unrelated to the split-phasedness, how can I tell
if this is a split-phase?

That's a start capacitor. I still don't know why Gingery would say to use only
a split-phase. The cap start motors are better.

GTO(John)

Well, I don't know a thing about motors. This one has a big cylindrical
thing mounted on top of it (parallel to the shaft). Is that a
capacitor? (I could post a picture if someone wants to see it.)

Yep, that's the housing for the start cap.

Bob Swinney
"PhysicsGenius" wrote in message
...
Well, I don't know a thing about motors. This one has a big cylindrical
thing mounted on top of it (parallel to the shaft). Is that a
capacitor? (I could post a picture if someone wants to see it.)

GTO69RA4 wrote:
Single phase just means is runs on normal household current, nothing
more. A
split phase motor doesn't have any capacitors on it, a cap-start has
one, a cap
start/run motor has two.

Split phase motors are actually the weakest and slowest of the three.
Less
starting torque than the other two. I have no clue why Gingery would
recommend
one, other than for cost reasons. Maybe the design isn't strong enough
for the
fast start a cap start motor would have. You can use any kind of motor
you want
on a lathe.

GTO(John)


I found a motor at the dump. It works great and appears to even have
been part of a woodshop at one point (covered with sawdust). What I'm
not sure of is if it fits the requirements Gingery lays down.

The frame is a little larger than NEMA 48, but that's not a big deal.
Gingery also says it should be "split phase", which from my research
seems to mean that it has an extra circuit in when it spins up to give
it extra torque for a fast (or just strong?) start. The plate on this
one has a box labeled "Phase" and in the box is the value "1". So
that's a single-phase motor then? If so, does that rule this one out,
even considering it's a 1/2 HP instead of the 1/4 Gingery lists as
minimum?

If that "Phase" box is unrelated to the split-phasedness, how can I tell
if this is a split-phase?

That's a start capacitor. I still don't know why Gingery would say to
use only a split-phase. The cap start motors are better.

As I recall, I don't think it was "use only", it was more
a matter of "split phase motors are easy to find for cheap
or free", especially old appliance motors. A cost issue,
basically. I think the 1/2 horse motor will do fine. More
to the point, what RPM's does it run at? This will tell you
if you have to change some pulley sizes to get it to work
at the speeds he selected... (worth doing, especially for
this motor).
--Glenn Lyford

Glenn Lyford wrote:
That's a start capacitor. I still don't know why Gingery would say to
use only a split-phase. The cap start motors are better.


As I recall, I don't think it was "use only", it was more
a matter of "split phase motors are easy to find for cheap
or free", especially old appliance motors. A cost issue,
basically. I think the 1/2 horse motor will do fine. More
to the point, what RPM's does it run at? This will tell you
if you have to change some pulley sizes to get it to work
at the speeds he selected... (worth doing, especially for
this motor).
--Glenn Lyford

The plate says 1725, just like Gingery's. It's a 110/220, though, and
has a wiring diagram on the other side that indicates maybe it could be
faster or slower at a different voltage. It's out on the cold, cold
back porch right now or I'd check that.

Ah, here's the exact quote from the book: "Any split phase motor of 1/4
HP or more will do the job." I took that to mean that anything that
*wasn't* a split phase motor wouldn't do the job. But your reading also
makes sense. This dual-interpretation issue is the exact same problem I
had with the lid. I'll be sure to document this when I actually get to
the point where I need to use the motor (I'm months away from that
still, at least).

Thanks!

The plate says 1725, just like Gingery's. It's a 110/220, though, and
has a wiring diagram on the other side that indicates maybe it could be
faster or slower at a different voltage.

No, this is done by running the windings in series or in parallel,
the speed remains the same, and is a function of the number of windings
and the line frequency (60 cycles per second in the US), minus some
fudge factor for "slip". Given the opportunity (probably not a big
issue for 1/2 hp), run motors on 220. The amperage draw is less, so they
don't pop breakers as much. I remember it as P=ixV, power is
current times voltage. For the same power (1/2 horse), if you double
the voltage, the amperage is half.

I don't think this will be a problem with the Gingery lathe, though,
you'll probably run into chatter from lack of stiffness long before
you are taking a heavy enough cut to pop the breaker.

Ah, here's the exact quote from the book: "Any split phase motor of 1/4
HP or more will do the job." I took that to mean that anything that
*wasn't* a split phase motor wouldn't do the job. But your reading also
makes sense. This dual-interpretation issue is the exact same problem I
had with the lid.

The key to interpreting Gingery is his emphasis on doing
this on a budget, not necessarily for best practice. He tries
to recommend his cheapest solution that will still work acceptably.
If you think another method will work, or even improve it, by
all means do so. Many others already have when they have built
his projects. If you decide to spend a little more money on a
nicer component because it will be easier to use or give a better
result, do not feel guilty unless low cost is a primary motivating
factor for you, as opposed to ending up with the tool. Low cost
was his driving factor, and it's why his books still sell very well.

I think his emphasis here was so that, of the _cheap_ motors, you'd
pick ones that would work. A shaded pole motor from a box fan
wouldn't work very well, for example. Any motor taken from a
larger tool, especially wood working tools that are notoriously power
hungry (ripping wood fibers is hard work) would be more than suitable.

Gingery does not recommend them merely because by and large, they
are not cheap, prices often start at $100 when new. If you can find
them cheap, then by all means do so. Just avoid ones that need
brushes, like the ones in a hand held circular saw (universal motor).
They're usually too fast and too loud. Oh, and ones that say
"Phases: 3" won't work on house current without additional work
(phase converter or VFD) either.

Does that help?
--Glenn Lyford

Glenn Lyford wrote:
The plate says 1725, just like Gingery's. It's a 110/220, though, and
has a wiring diagram on the other side that indicates maybe it could be
faster or slower at a different voltage.


No, this is done by running the windings in series or in parallel,
the speed remains the same, and is a function of the number of windings
and the line frequency (60 cycles per second in the US), minus some
fudge factor for "slip". Given the opportunity (probably not a big
issue for 1/2 hp), run motors on 220. The amperage draw is less, so they
don't pop breakers as much. I remember it as P=ixV, power is
current times voltage. For the same power (1/2 horse), if you double
the voltage, the amperage is half.

Oh I see, I thought maybe it held current constant to double the power.
Now that I think about it, it would have been labled 1/2-1 HP instead
of just 1/2 HP if that was the case.

I don't think this will be a problem with the Gingery lathe, though,
you'll probably run into chatter from lack of stiffness long before
you are taking a heavy enough cut to pop the breaker.


Ah, here's the exact quote from the book: "Any split phase motor of 1/4
HP or more will do the job." I took that to mean that anything that
*wasn't* a split phase motor wouldn't do the job. But your reading also
makes sense. This dual-interpretation issue is the exact same problem I
had with the lid.


The key to interpreting Gingery is his emphasis on doing
this on a budget, not necessarily for best practice. He tries
to recommend his cheapest solution that will still work acceptably.
If you think another method will work, or even improve it, by
all means do so. Many others already have when they have built
his projects. If you decide to spend a little more money on a
nicer component because it will be easier to use or give a better
result, do not feel guilty unless low cost is a primary motivating
factor for you, as opposed to ending up with the tool. Low cost
was his driving factor, and it's why his books still sell very well.

This is good advice on how to interpret Gingery. Of course, it only
helps if I know which items are the "cheap but acceptable" ones and
which are the "excellent for this purpse if you can get it" ones. Not
knowing anything about motors, I couldn't do that here. I will surely
have the same problem at several other stages.

But that's why I'm doing this, to learn. I don't really have a
"primary" motivating factor, just 3 subfactors. Learning, low-cost and
having-the-tool.

I put a 100V DC motor (the GE 2HP surplus treadmill units) with no fancy
frame with pulleys and idlers. It works great (way better that Daves plan,
I get much wider speed ranges).

"PhysicsGenius" wrote in message
...
Glenn Lyford wrote:
The plate says 1725, just like Gingery's. It's a 110/220, though, and
has a wiring diagram on the other side that indicates maybe it could be
faster or slower at a different voltage.


No, this is done by running the windings in series or in parallel,
the speed remains the same, and is a function of the number of windings
and the line frequency (60 cycles per second in the US), minus some
fudge factor for "slip". Given the opportunity (probably not a big
issue for 1/2 hp), run motors on 220. The amperage draw is less, so
they
don't pop breakers as much. I remember it as P=ixV, power is
current times voltage. For the same power (1/2 horse), if you double
the voltage, the amperage is half.

Oh I see, I thought maybe it held current constant to double the power.
Now that I think about it, it would have been labled 1/2-1 HP instead
of just 1/2 HP if that was the case.

I don't think this will be a problem with the Gingery lathe, though,
you'll probably run into chatter from lack of stiffness long before
you are taking a heavy enough cut to pop the breaker.


Ah, here's the exact quote from the book: "Any split phase motor of 1/4
HP or more will do the job." I took that to mean that anything that
*wasn't* a split phase motor wouldn't do the job. But your reading also
makes sense. This dual-interpretation issue is the exact same problem I
had with the lid.


The key to interpreting Gingery is his emphasis on doing
this on a budget, not necessarily for best practice. He tries
to recommend his cheapest solution that will still work acceptably.
If you think another method will work, or even improve it, by
all means do so. Many others already have when they have built
his projects. If you decide to spend a little more money on a
nicer component because it will be easier to use or give a better
result, do not feel guilty unless low cost is a primary motivating
factor for you, as opposed to ending up with the tool. Low cost
was his driving factor, and it's why his books still sell very well.

This is good advice on how to interpret Gingery. Of course, it only
helps if I know which items are the "cheap but acceptable" ones and
which are the "excellent for this purpse if you can get it" ones. Not
knowing anything about motors, I couldn't do that here. I will surely
have the same problem at several other stages.

But that's why I'm doing this, to learn. I don't really have a
"primary" motivating factor, just 3 subfactors. Learning, low-cost and
having-the-tool.

Dave Keith wrote:
I put a 100V DC motor (the GE 2HP surplus treadmill units) with no fancy
frame with pulleys and idlers. It works great (way better that Daves plan,
I get much wider speed ranges).

That's what made me check this motor, which has been sitting unmoved on
my back porch for something like 18 months. "American Science &
Surplus" has treadmill motors for around $40 and I wasn't sure if I
should get one.