General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article DoNotSpamthegoat4-15058F.10400322122004
@library.airnews.net, DoNotSpamthegoat4
@airmail.net.com.org.gov.tw.ch.ru says...
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.


Bodine has been printing the "Small Motor, Gearmotor, and
Control Handbook" for many years. It's a pretty good, not
too technical overview of many small motor types. It looks
like it may be online, but you have to register...

http://www.bodine-electric.com/Tools/Handbook.asp

Ned Simmons

B.B. wrote:

General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.


Your question is imprecise and unclear. I'm assuming you are asking about AC
electric motors for use in a home shop. If you're wondering about
retrofitting your ultralight with a diesel, this may not be for you.

My first and often-repeated suggestion is to go visit your local library.
Sometimes you will get lucky and find a good book. There are lots and lots
of bad books on electric motors, but all of them have many basics.

If you live in the US then the power is 60 cycles per second, or 60 Hz. If
you live in Canada, then the power is 50 Hz. Motors made for 50 Hz. have more
copper in them than motors made for 60 Hz. and as such are more desirable.
Some guys don't know that almost any 50 Hz. motor will run fine at 60 Hz.
and most 60 Hz. motors will work on 50 Hz.

Motors run at an approximate RPM. This RPM is related to the power line
frequency. For 60 Hz. power, this RPM = (3600 / N) - slip. If the motor
has one pole then it is commonly rated at 3450 from which you can easily
see it would run at 3600 except for the slip. Less load, less slip; more
load, more slip up until stall. If the motor has 2 poles, then it will
likely be rated for 1760 rpm or 1730 rpm or 1800 rpm or something like
that. If you see a motor that says 1430 rpm then you know it's a 50 Hz
2-pole motor.

Motors come in single phase and three phase. Single-phase motors often
have a centrifugal switch that makes a connection until the rotor is
spinning fast enough to trip the centrifugal switch. You will hear this
switch audibly *click* as a single-phase motor slows. This switch either
connects or disconnects start capacitors. Single-phase motors that don't
start usually need a new start capacitor. These capacitors are electrolytic
capacitors and such capacitors don't last too long in service, maybe 10-15
years, because they dry out and lose their capacity. Three phase motors
don't need start caps but they need three phase power.

Motors can be often be run to work at more than one voltage or in either
direction. See the reference:
http://www.metalwebnews.com/howto/el.../elec-mtr.html

There's a lot more I could write, but that's it for now. - GWE

I picked up a book "Managing Motors" by Richard L. Nailen. Pretty much a
text book but really orientated to the 'how to' side rather than the
theory side. even has a decent section on phase converters. Out of print
and out of stock at Amazon. 1996 copyright.



B.B. wrote:
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

look at the application notes that the various manufactures put out, for
example Minarik. And, there are lots of text books on the subject that are
considered of no value by most book sellers, so there's another avenue

"B.B." u wrote in message
news
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

Try http://www.electricmotors.machinedes...m/BDEList.aspx

as a start.

"B.B." u wrote in message
news
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

In article Nuiyd.21033$up.18608@lakeread08,
"Randal O'Brian" wrote:

Try http://www.electricmotors.machinedes...m/BDEList.aspx

as a start.

Ah! Perfect! Thanks.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

"Grant Erwin" wrote in message
...
snip
If you live in the US then the power is 60 cycles per second, or 60 Hz. If
you live in Canada, then the power is 50 Hz. Motors made for 50 Hz. have
more
copper in them than motors made for 60 Hz. and as such are more desirable.
Some guys don't know that almost any 50 Hz. motor will run fine at 60 Hz.
and most 60 Hz. motors will work on 50 Hz.
snip

Grant - are you sure about 50 Hz power in Canada? I spent some time there
30 years ago (no, not avoiding the draft) and seem to recall it was 60 Hz
and I have a vague recollection that power can be shared across the border.
Could be wrong on both counts, though.

Mike

In article ,
Grant Erwin wrote:

Your question is imprecise and unclear. I'm assuming you are asking about AC
electric motors for use in a home shop. If you're wondering about
retrofitting your ultralight with a diesel, this may not be for you.

Yeah, sorry about that. I know there's a ton of info so I should
shave it down a bit. AC motors 10hp and smaller. Mostly the stuff
found in tools rather than tape decks.

[...]

http://www.metalwebnews.com/howto/el.../elec-mtr.html

There's a lot more I could write, but that's it for now. - GWE

Thanks. Very helpful.
One question for now: What is power factor correction? I've found
the term several times today, but not the definition.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

BB

I get alot of help with motor design information from a book (paperback)
written by Irving M. Gottlieb, titled Electric Motors and Control
Techniques.

Jerry



"B.B." u wrote in message
news
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

B.B. wrote:

One question for now: What is power factor correction? I've found
the term several times today, but not the definition.


This is a nasty one. If you have an ideal power source providing a
sinusoidal voltage, then if you put that in series with a resistor,
current will flow, and the current waveform would be a sinewave. If
you then add a capacitor across the voltage source, current would
also flow through the capacitor. If you looked at the current waveform
across the resistor on the same scope trace as the current waveform
across the capacitor, they would look very similar (well, one would
be bigger than the other) but their peaks and valleys would have
shifted relative to each other. In fact, the current waveform through
the capacitor is "phase shifted" by +90° relative to the current
waveform through the resistor. Similarly, if you apply the sinusoidal
power to an inductor, its current waveform would also be a sinewave,
but it would be phase shifted by -90° relative to the waveform of
the current through the resistor.

OK, now here's the tricky part. Current flowing through a resistor
dissipates power, and it is called "real current". The term "real"
here is mathematical - it means that when you express the current
as a complex number it only has a real part and its imaginary component
is zero. However, current through either an ideal capacitor or an ideal
inductor does not dissipate power. This current is called "imaginary
current" for similar reasons.

OK so far?

Now let's move to a real-world situation. Electric AC motors are magnetic
machines. They have windings which "look" very much like an inductor. In
reality, any physical component has some resistance and almost certainly
some capacitance too, but if you compare the current waveform of an AC
motor with that of the current waveform into a resistor, you will see
that the motor's current is phase-shifted nearly -90° which is why it
is said to "look inductive". The way you can make the current flowing into
an AC motor look more like current flowing into a resistor is to add some
run capacitors across the motor leads. If you add about the right amount
of capacitors, then the power flowing will look like "real power".

The power company cares about this passionately. Why should you? Here's
the deal - if you are consuming 1 hp of power for your bench grinder, for
example, then current is flowing sufficient to provide 1 hp of real power.
But current is also flowing because the grinder motor looks inductive.
This current doesn't show up on your power bill but it surely will burn
up a wire or melt heaters in your motor control circuit. The way to minimize
the total (real + imaginary) current in your motor wiring is to add the
right amount of capacitance. This is called "power factor correction."

OK, I have never been a practicing electrical engineer -- my thing was
semiconductors and software. There are real EEs on this NG who will almost
certainly take exception to some of my wording, especially because it's
all off the top of my head, from memory, which memory all comes from college
which was more than 2 decades ago. However, I believe it's sufficient to
impart the essentials.

GWE

Mike Henry wrote:


Grant - are you sure about 50 Hz power in Canada? I spent some time there
30 years ago (no, not avoiding the draft) and seem to recall it was 60 Hz
and I have a vague recollection that power can be shared across the border.
Could be wrong on both counts, though.

Nope, I'm *not* sure. But I think so. I also live in NW Washington, right
up next to BC, and I see a lot of 50Hz salvage motors that the salvage
guys describe as Canadian. That works to my advantage if they don't know
the motors work on US power.

Anyway, I'm really often wrong. But 50Hz motors certainly exist, and
is certainly the standard in England.

Grant

On Wed, 22 Dec 2004 14:49:47 -0800, Grant Erwin
wrote:

B.B. wrote:

One question for now: What is power factor correction? I've found
the term several times today, but not the definition.


This is a nasty one. If you have an ideal power source providing a
sinusoidal voltage, then if you put that in series with a resistor,
current will flow, and the current waveform would be a sinewave. If
you then add a capacitor across the voltage source, current would
also flow through the capacitor. If you looked at the current waveform
across the resistor on the same scope trace as the current waveform
across the capacitor, they would look very similar (well, one would
be bigger than the other) but their peaks and valleys would have
shifted relative to each other. In fact, the current waveform through
the capacitor is "phase shifted" by +90° relative to the current
waveform through the resistor. Similarly, if you apply the sinusoidal
power to an inductor, its current waveform would also be a sinewave,
but it would be phase shifted by -90° relative to the waveform of
the current through the resistor.

OK, now here's the tricky part. Current flowing through a resistor
dissipates power, and it is called "real current". The term "real"
here is mathematical - it means that when you express the current
as a complex number it only has a real part and its imaginary component
is zero. However, current through either an ideal capacitor or an ideal
inductor does not dissipate power. This current is called "imaginary
current" for similar reasons.

OK so far?

Now let's move to a real-world situation. Electric AC motors are magnetic
machines. They have windings which "look" very much like an inductor. In
reality, any physical component has some resistance and almost certainly
some capacitance too, but if you compare the current waveform of an AC
motor with that of the current waveform into a resistor, you will see
that the motor's current is phase-shifted nearly -90° which is why it
is said to "look inductive". The way you can make the current flowing into
an AC motor look more like current flowing into a resistor is to add some
run capacitors across the motor leads. If you add about the right amount
of capacitors, then the power flowing will look like "real power".

The power company cares about this passionately. Why should you? Here's
the deal - if you are consuming 1 hp of power for your bench grinder, for
example, then current is flowing sufficient to provide 1 hp of real power.
But current is also flowing because the grinder motor looks inductive.
This current doesn't show up on your power bill but it surely will burn
up a wire or melt heaters in your motor control circuit. The way to minimize
the total (real + imaginary) current in your motor wiring is to add the
right amount of capacitance. This is called "power factor correction."

OK, I have never been a practicing electrical engineer -- my thing was
semiconductors and software. There are real EEs on this NG who will almost
certainly take exception to some of my wording, especially because it's
all off the top of my head, from memory, which memory all comes from college
which was more than 2 decades ago. However, I believe it's sufficient to
impart the essentials.

GWE

Electric companies do indeed care passionately about the power factor.
Those big grey cylinders you see up on power poles are capacitors used
to correct the power factor in household electricity. (Most of a
household's load is electric motors, hence inductive.)

--RC

"Sometimes history doesn't repeat itself. It just yells
'can't you remember anything I've told you?' and lets
fly with a club.
-- John W. Cambell Jr.

"B.B." u wrote in message
news
General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

If anyone is interested in basic DC motor theory and transfer functions, I
recently posted some information in response to a question in the LabView
newsgroup. I'll leave it up for a few more days-it's in JPG format...

http://home.tir.com/~artemus/DC%20motors/

Grant Erwin wrote:


If you live in the US then the power is 60 cycles per second, or 60 Hz. If
you live in Canada, then the power is 50 Hz. Motors made for 50 Hz. have more
copper in them than motors made for 60 Hz. and as such are more desirable.
Some guys don't know that almost any 50 Hz. motor will run fine at 60 Hz.
and most 60 Hz. motors will work on 50 Hz.

What part of Canada did you get this from? Canada has been running 60Hz
for, well, about forever.

European stuff is more likely to be 50Hz (and 220v, vice 110).

Cheers
Trevor Jones

"Grant Erwin" wrote in message
...
B.B. wrote:

General stuff, like principals of operation, common configurations,
voltages, dimensions, and various control schemes?
I know bits and pieces of what I've picked up in here through various
discussions, but now I'm curious and just want a pile of information to
dig through.


Your question is imprecise and unclear. I'm assuming you are asking about
AC
electric motors for use in a home shop. If you're wondering about
retrofitting your ultralight with a diesel, this may not be for you.

My first and often-repeated suggestion is to go visit your local library.
Sometimes you will get lucky and find a good book. There are lots and lots
of bad books on electric motors, but all of them have many basics.

If you live in the US then the power is 60 cycles per second, or 60 Hz. If
you live in Canada, then the power is 50 Hz. Motors made for 50 Hz. have
more
copper in them than motors made for 60 Hz. and as such are more desirable.
Some guys don't know that almost any 50 Hz. motor will run fine at 60 Hz.
and most 60 Hz. motors will work on 50 Hz.

Motors run at an approximate RPM. This RPM is related to the power line
frequency. For 60 Hz. power, this RPM = (3600 / N) - slip. If the motor
has one pole then it is commonly rated at 3450 from which you can easily
see it would run at 3600 except for the slip. Less load, less slip; more
load, more slip up until stall. If the motor has 2 poles, then it will
likely be rated for 1760 rpm or 1730 rpm or 1800 rpm or something like
that. If you see a motor that says 1430 rpm then you know it's a 50 Hz
2-pole motor.

I believe that a two pole AC motor typically runs around 3450 RPM at 60 HZ,
and a four pole AC motor runs around 1750 RPM at 60 HZ.



Motors come in single phase and three phase. Single-phase motors often
have a centrifugal switch that makes a connection until the rotor is
spinning fast enough to trip the centrifugal switch. You will hear this
switch audibly *click* as a single-phase motor slows. This switch either
connects or disconnects start capacitors. Single-phase motors that don't
start usually need a new start capacitor. These capacitors are
electrolytic
capacitors and such capacitors don't last too long in service, maybe 10-15
years, because they dry out and lose their capacity. Three phase motors
don't need start caps but they need three phase power.

Motors can be often be run to work at more than one voltage or in either
direction. See the reference:
http://www.metalwebnews.com/howto/el.../elec-mtr.html

There's a lot more I could write, but that's it for now. - GWE

In article ,
Grant Erwin wrote:

B.B. wrote:

One question for now: What is power factor correction? I've found
the term several times today, but not the definition.


This is a nasty one. If you have an ideal power source providing a
sinusoidal voltage, then if you put that in series with a resistor,
current will flow, and the current waveform would be a sinewave. If
you then add a capacitor across the voltage source, current would
also flow through the capacitor. If you looked at the current waveform
across the resistor on the same scope trace as the current waveform
across the capacitor, they would look very similar (well, one would
be bigger than the other) but their peaks and valleys would have
shifted relative to each other. In fact, the current waveform through
the capacitor is "phase shifted" by +90° relative to the current
waveform through the resistor. Similarly, if you apply the sinusoidal
power to an inductor, its current waveform would also be a sinewave,
but it would be phase shifted by -90° relative to the waveform of
the current through the resistor.

So I'd get what looks like a plot of sin(x) and sin(x+pi/2) {radians}
if I compared the power supply with the power through a capacitor.
Likewise I'd get what looks like a plot of sin(x) and sin(x-pi/2) if I
compared the power supply with the power through an inductor. Correct?

OK, now here's the tricky part. Current flowing through a resistor
dissipates power, and it is called "real current". The term "real"
here is mathematical - it means that when you express the current
as a complex number it only has a real part and its imaginary component
is zero. However, current through either an ideal capacitor or an ideal
inductor does not dissipate power. This current is called "imaginary
current" for similar reasons.

OK so far?

I believe so.

Now let's move to a real-world situation. Electric AC motors are magnetic
machines. They have windings which "look" very much like an inductor. In
reality, any physical component has some resistance and almost certainly
some capacitance too, but if you compare the current waveform of an AC
motor with that of the current waveform into a resistor, you will see
that the motor's current is phase-shifted nearly -90° which is why it
is said to "look inductive". The way you can make the current flowing into
an AC motor look more like current flowing into a resistor is to add some
run capacitors across the motor leads. If you add about the right amount
of capacitors, then the power flowing will look like "real power".

The power company cares about this passionately. Why should you? Here's
the deal - if you are consuming 1 hp of power for your bench grinder, for
example, then current is flowing sufficient to provide 1 hp of real power.
But current is also flowing because the grinder motor looks inductive.
This current doesn't show up on your power bill but it surely will burn
up a wire or melt heaters in your motor control circuit. The way to minimize
the total (real + imaginary) current in your motor wiring is to add the
right amount of capacitance. This is called "power factor correction."

OK, I have never been a practicing electrical engineer -- my thing was
semiconductors and software. There are real EEs on this NG who will almost
certainly take exception to some of my wording, especially because it's
all off the top of my head, from memory, which memory all comes from college
which was more than 2 decades ago. However, I believe it's sufficient to
impart the essentials.

I think I get it. If you don't have a power factor correction the
imaginary part of the current gets out of phase with the real current.
I take it total current(T)^2 = real current(R)^2 + imaginary
current(I)^2. Or T=sqrt(R^2+I^2). As long as R = I, T is equal to R,
but if you get 90 degrees out of phase T is always 1. Or whatever your
current is limited to by the wire resistance and Ohm's law. I think.
So, by adding the right capacitance you wind up with a wave of
R=sin(x) and I=sin(x+pi/2-pi/2). T stays little, and nothing fries
unexpectedly.
Am I close enough for horseshoes?

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

On Wed, 22 Dec 2004 13:00:33 -0600, "Mike Henry"
wrote:


"Grant Erwin" wrote in message
...
snip
If you live in the US then the power is 60 cycles per second, or 60 Hz. If
you live in Canada, then the power is 50 Hz. Motors made for 50 Hz. have
more
copper in them than motors made for 60 Hz. and as such are more desirable.
Some guys don't know that almost any 50 Hz. motor will run fine at 60 Hz.
and most 60 Hz. motors will work on 50 Hz.
snip

Grant - are you sure about 50 Hz power in Canada? I spent some time there
30 years ago (no, not avoiding the draft) and seem to recall it was 60 Hz
and I have a vague recollection that power can be shared across the border.
Could be wrong on both counts, though.

Mike

Many years ago (1950 ?) the last ares of 25Hz power were switched over
to 60Hz. I have never seen 50Hz although the odd 50 Hz motor does show
up at yard sales.
Gerry :-)}
London, Canada

Grant Erwin wrote:

Mike Henry wrote:


Grant - are you sure about 50 Hz power in Canada? I spent some time
there 30 years ago (no, not avoiding the draft) and seem to recall it
was 60 Hz and I have a vague recollection that power can be shared
across the border. Could be wrong on both counts, though.


Nope, I'm *not* sure. But I think so. I also live in NW Washington, right
up next to BC, and I see a lot of 50Hz salvage motors that the salvage
guys describe as Canadian. That works to my advantage if they don't know
the motors work on US power.

Anyway, I'm really often wrong. But 50Hz motors certainly exist, and
is certainly the standard in England.

Grant
Europe and Japan. - Maybe elsewhere.

Older English areas - South East Asia places...

When I was with an ATE company - automated Test Equipment - we had to have
50 and 60 hz and many voltage types of inputs.

Tape drives had to have new wheels, pulleys, ..... Fans had to be different.

Motors are maybe 70% strength if 50hz on a 60 hz line. They also tend to heat more.

I know a large German handler - about the size of a good living room - maybe larger -
many parts in parallel - the machine was something else, but didn't function just
like they liked and they decided to switch out the 50 hz motors to 60 and the
machine came up to speed and quality.

I bet they came off machinery (asia based or eu based) and were swapped out to work.
Then dump the motors on the local market.

Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder