Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most shop
machines. There are some big machines out there, but for most shop machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from many
electric companies by going 3 phase you can get a smoother operating motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most shop
machines. There are some big machines out there, but for most shop machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from many
electric companies by going 3 phase you can get a smoother operating motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)



Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

"Pete C." wrote in message
ter.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)



Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....
--
EA

The answer is velocity modulation and torque. Under load the motor shaft accelerates and decelerates at 60 Hz. That speed
variation is much greater with a single phase motor. I can actually see this in a fine finish cut on my 10" SB lathe in high gear
with a single phase motor. If I use a 3 phase motor, the finish ripple is non-existent. With 3 Ph power, the starting torque is
higher and the in-rush current is much less. On your 5 hp compressor, don't believe it. Put an amp meter on it and work the
numbers. Even without PF compensation, you won't get anything near 5 hp.
Steve

"Bob La Londe" wrote in message ...
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that runs on 120V. It draw close to 20 amps on startup,
but...

Straight single phase 220V is more than adequate for any power for most shop machines. There are some big machines out there,
but for most shop machines its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies often charged based on the peak demand of the leg
drawing the most current at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from many electric companies by going 3 phase you can get a
smoother operating motor with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is a-whole-nuther conversation.)

Existential Angst wrote:

"Pete C." wrote in message
ter.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)



Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....

Steppers are typically 4 phase...

On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

It draw close to 20 amps on startup, but... Straight single phase
220V is more than adequate for any power for most shop machines.
There are some big machines out there, but for most shop machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from many
electric companies by going 3 phase you can get a smoother operating motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

All commercial shops have 3 phase.

i

"Ignoramus23708" wrote in message
...
On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Yes he does.... well, 5 Sears hp...

--
EA



It draw close to 20 amps on startup, but... Straight single phase
220V is more than adequate for any power for most shop machines.
There are some big machines out there, but for most shop machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

All commercial shops have 3 phase.

i

On 08/23/2010 09:11 AM, Existential Angst wrote:
"Pete wrote in message
ter.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)



Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....

1 phase: 0 degrees, with return.

2 phase: 0 degrees, 180 degrees. Same as one phase, only we've renamed
the return.

3 phase: 0 degrees, 120 degrees, -120 degrees. Because the three phases
always sum to 0, a neutral wire is only needed to carry current for
single-phase wiring on one or more leg, and for broken machines.

4 phase: 0 degrees, 90 degrees, 180 degrees, -90 degrees. With just a
bit of thought you can see that this is really only two independent
phases, with returns. You could go to one return, but then it'd have to
carry current so couldn't really be a 'neutral'. Transformers would be
weird. Motors would be weird. The 3 phase motor hook-up dance "try it
out and swap two wires if it goes backwards" wouldn't work -- get phases
wrong and all hell would break loose.

5 phase: five wires instead of three, with the electrical phases 72
degrees off. There's no significant smoothness advantage, and now if
you get the wrong two phases swapped all hell breaks loose instead of
just having a motor run backwards.

6-phase: just like three phase, only with individual returns. Why?

etc.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Mon, 23 Aug 2010 08:55:11 -0700, "Bob La Londe"
wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most shop
machines. There are some big machines out there, but for most shop machines
its fine.

In addition to (or support of) factors others have mentioned:

A 3-phase motor can be "plug reversed" while a single phase motor must
come to a complete stop before it can be started in the opposite
direction. 3-phase motors need no starting coils or circuitry which
makes them cheaper and much more reliable.

A 3-phase motor excited with balanced 3-phase power has zero torque
ripple. Not reduced, zero. The flow of power to such a motor is
constant.

These attributes are also exhibited by a 2-phase motor driven by
2-phase power, and there once was 2-phase power and 2-phase motors.
But 3-phase has a number of distribution advantages over 2-phase, so
it has become the norm.

Ignoramus23708 wrote:

On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Correct.


All commercial shops have 3 phase.

Incorrect. Most commercial shops have three phase power, but there are
plenty that have to make due with single phase power. These are mostly
shops lucky enough to be located in the middle of nowhere and they get
by with phase converters and VFDs.

On Aug 23, 11:38*am, "Pete C." wrote:
Existential Angst wrote:

"Pete C." wrote in message
ster.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. *I have a compressor with a 5 horse motor that
runs on 120V. *It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. *There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. * *Price of electricity. *It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. *By balancing the load you can reduce your power bill.

2. * *Smoother operation. *With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better? *
Seriously, tho....

Steppers are typically 4 phase...

Steppers are typically Two phase. Two windings. You can drive them
with a four step or an eight step sequence.
Micro stepping is just a smooth transition from one of those steps to
the next.

There are some five phase steppers. And mostly two phase windings in
steppers. Any other variation will be quite rare.

On Aug 23, 11:11*am, "Existential Angst" wrote:
"Pete C." wrote in message

ter.com...





Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. *I have a compressor with a 5 horse motor that
runs on 120V. *It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. *There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. * *Price of electricity. *It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. *By balancing the load you can reduce your power bill.

2. * *Smoother operation. *With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better? *
Seriously, tho....
--
EA

Actually, Two phase, three phase, any polyphase circuit can be
converted into another polyphase circuit.
You can take three phase and get two phase or visa-versa. Or Five or
12 or whatever you want.
I used to work where we took three phase power and converted it into
twelve phase power with transformers.

Look up Schott-T transformers for more magic.

The original generators at Niagara Falls were two phase, (IIRC) and
transformers converted the power into three phase for power
distribution.

I have been told, but did not confirm that three phase wiring is the
most economical for copper vs power delivered.

Two phase power is two phases 90 degrees part. NOT 180 apart as
someone suggested.

On Aug 23, 12:02*pm, Tim Wescott wrote:
On 08/23/2010 09:11 AM, Existential Angst wrote:



"Pete *wrote in message
ster.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. *I have a compressor with a 5 horse motor that
runs on 120V. *It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. *There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. * *Price of electricity. *It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. *By balancing the load you can reduce your power bill.

2. * *Smoother operation. *With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better? *
Seriously, tho....

1 phase: 0 degrees, with return.

2 phase: 0 degrees, 180 degrees. *Same as one phase, only we've renamed
the return.

3 phase: 0 degrees, 120 degrees, -120 degrees. *Because the three phases
always sum to 0, a neutral wire is only needed to carry current for
single-phase wiring on one or more leg, and for broken machines.

4 phase: 0 degrees, 90 degrees, 180 degrees, -90 degrees. *With just a
bit of thought you can see that this is really only two independent
phases, with returns. *You could go to one return, but then it'd have to
carry current so couldn't really be a 'neutral'. *Transformers would be
weird. *Motors would be weird. *The 3 phase motor hook-up dance "try it
out and swap two wires if it goes backwards" wouldn't work -- get phases
wrong and all hell would break loose.

5 phase: five wires instead of three, with the electrical phases 72
degrees off. *There's no significant smoothness advantage, and now if
you get the wrong two phases swapped all hell breaks loose instead of
just having a motor run backwards.

6-phase: just like three phase, only with individual returns. *Why?

etc.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Two phase is two circuits 90 degrees out of phase. That is NOT four
phase.

"Bob La Londe" wrote in message
...
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop machines. There are some big machines out there, but for most shop
machines its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from many
electric companies by going 3 phase you can get a smoother operating motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)




Single phase and split-phase motors draw an unbalanced magnetic flux
junction matrix that if the deviation is uncompensated, they can create a
tear in the time-space continuum.

On Mon, 23 Aug 2010 12:48:53 -0400, "Existential Angst"
wrote:

"Ignoramus23708" wrote in message
...
On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Yes he does.... well, 5 Sears hp...

Yep, everyone knows Sears compares to the number of Shetland ponies.

Quincy compares to the number of Clydesdales.

Karl

On 08/23/2010 11:32 AM, Cross-Slide wrote:
On Aug 23, 11:11 am, "Existential wrote:
"Pete wrote in message

ter.com...





Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)

Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....
--
EA

Actually, Two phase, three phase, any polyphase circuit can be
converted into another polyphase circuit.
You can take three phase and get two phase or visa-versa. Or Five or
12 or whatever you want.
I used to work where we took three phase power and converted it into
twelve phase power with transformers.

Look up Schott-T transformers for more magic.

The original generators at Niagara Falls were two phase, (IIRC) and
transformers converted the power into three phase for power
distribution.

I have been told, but did not confirm that three phase wiring is the
most economical for copper vs power delivered.

Two phase power is two phases 90 degrees part. NOT 180 apart as
someone suggested.

I was being lazy. Yes, two phase, as marketed, is 90 degrees apart, not
just single phase with a return.

Two phase (by your correct terminology) needs at least three conductors,
with legs at 0 degrees, 90 degrees, and a return whose current is -135
degrees away from the current in the other two (or with separate returns
for each phase). So it requires the same number of conductors as three
phase, but the return wire has to carry 41% more current than either of
the other two conductors.

Three phase still needs three conductors, but the requirements on each
conductor is the same as any other. It has a whole bunch of handy
symmetries that make it easier to use than two phase (which was really
my point in my other post, where I got too fast and loose with terminology).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 08/23/2010 09:48 AM, Existential Angst wrote:
id wrote in message
...
On 2010-08-23, Bob La wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Yes he does.... well, 5 Sears hp...

Maybe Sears just misspells "ladies of the evening power".

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

All commercial shops have 3 phase.

Oh Lord how I wish that were true!!!

Not all do... But the vast majority do.

We sell to large manufacturers world-wide and I'd guess maybe 5% don't have
three phase here in the USA whereas outside the USA the numebrs might be a
bit *lower* than that.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://tinyurl.com/AutoDrill-Facebook

V8013-R

Bob,

Just to paly devil's advocate here... Everyone is busting on you for saying
you have a 5 HP, single phase motor that draws 20 amps on your compressor.

AOS motor
Model K307
1800 RPM
Single phase
F213TC frame
1.15 service factor
23.0 FLA at 220 single ph.
No 120 option provided in the book.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://tinyurl.com/AutoDrill-Facebook

V8013-R

On Aug 23, 3:18*pm, "Joe AutoDrill" wrote:
Bob,

Just to paly devil's advocate here... *Everyone is busting on you for saying
you have a 5 HP, single phase motor that draws 20 amps on your compressor..

AOS motor
Model K307
1800 RPM
Single phase
F213TC frame
1.15 service factor
23.0 FLA at 220 single ph.
No 120 option provided in the book.
--

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:http://www.AutoDrill.com
Multiple Spindle Drills:http://www.Multi-Drill.com
Production Tapping:http://Production-Tapping-Equipment.com/
Flagship Site:http://www.Drill-N-Tap.com
VIDEOS:http://www.youtube.com/user/AutoDrill
TWITTER:http://twitter.com/AutoDrill
FACEBOOK:http://tinyurl.com/AutoDrill-Facebook

V8013-R

Joe,
That example is drawing 23 amps at 220 volts.
NO Way you could get 5 HSP from half the voltage.
That is what they are pointing out. The amps times voltage does not
yield 5 HSP.

Joe,
That example is drawing 23 amps at 220 volts.
NO Way you could get 5 HSP from half the voltage.
That is what they are pointing out. The amps times voltage does not
yield 5 HSP.

That was sorta my point. 23 FLA at 220v is roughly 46 FLA at 120v - which
AO Smith didn't even offer as an option.

Most of the HP ratings on consumer products are "peak" HP. ...and they
define peak as what it can out out for about 1/10th of a second.

A *VERY* common misconception thanks to creative advertising and labeling.
We run into it all the time with VAC systems, drill presses and the like.

Heck, I've got a 3 HP hand-held lazer pointer right here. grin

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://tinyurl.com/AutoDrill-Facebook

V8013-R

Joe,
That example is drawing 23 amps at 220 volts.
NO Way you could get 5 HSP from half the voltage.
That is what they are pointing out. The amps times voltage does not
yield 5 HSP.

That was sorta my point. 23 FLA at 220v is roughly 46 FLA at 120v - which
AO Smith didn't even offer as an option.

Most of the HP ratings on consumer products are "peak" HP. ...and they
define peak as what it can out out for about 1/10th of a second.

A *VERY* common misconception thanks to creative advertising and labeling.
We run into it all the time with VAC systems, drill presses and the like.

Heck, I've got a 3 HP hand-held lazer pointer right here. grin

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill
TWITTER: http://twitter.com/AutoDrill
FACEBOOK: http://tinyurl.com/AutoDrill-Facebook

V8013-R

On 08/23/2010 01:45 PM, Cross-Slide wrote:
On Aug 23, 3:18 pm, "Joe wrote:
Bob,

Just to paly devil's advocate here... Everyone is busting on you for saying
you have a 5 HP, single phase motor that draws 20 amps on your compressor.

AOS motor
Model K307
1800 RPM
Single phase
F213TC frame
1.15 service factor
23.0 FLA at 220 single ph.
No 120 option provided in the book.
--

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:http://www.AutoDrill.com
Multiple Spindle Drills:http://www.Multi-Drill.com
Production Tapping:http://Production-Tapping-Equipment.com/
Flagship Site:http://www.Drill-N-Tap.com
VIDEOS:http://www.youtube.com/user/AutoDrill
TWITTER:http://twitter.com/AutoDrill
FACEBOOK:http://tinyurl.com/AutoDrill-Facebook

V8013-R

Joe,
That example is drawing 23 amps at 220 volts.
NO Way you could get 5 HSP from half the voltage.
That is what they are pointing out. The amps times voltage does not
yield 5 HSP.

Well, theoretically you could get 5HP if you didn't mind drawing well
over 30A.

But that would be a very odd thing to do if you had 220, and certainly
isn't consistent with the "draws 20A at startup" (unless it then
proceeds to draw over 30A!).

Remember: in theory, theory in practice are the same. In practice, of
course, they're different.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Mon, 23 Aug 2010 16:13:48 -0400, "Joe AutoDrill"
wrote:

All commercial shops have 3 phase.

Oh Lord how I wish that were true!!!

Not all do... But the vast majority do.

We sell to large manufacturers world-wide and I'd guess maybe 5% don't have
three phase here in the USA whereas outside the USA the numebrs might be a
bit *lower* than that.

Indeed!

One of the advantages OmniTurn CNC lathes had over their
competiton..they would run on their VFDs on single phase..though abiet
at a slightly derated power. We spec'd and installed the highest
powered, most efficient VFD under single phase, for exactly that
reason.

Have LOTS of them in shops with no 3 ph.

Gunner




I am the Sword of my Family
and the Shield of my Nation.
If sent, I will crush everything you have built,
burn everything you love,
and kill every one of you.
(Hebrew quote)

"Pete C." wrote:


Ignoramus23708 wrote:

On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Correct.

Just like I don't have a 6.5hp Sears shop vac. It was a gift, I didn't fall for it.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On 8/24/2010 3:02 AM, Tim Wescott wrote:

6-phase: just like three phase, only with individual returns. Why?

etc.


I was thinking of making a 7-phase system. Reason was, a permanent
magnet alternator on a motorcycle's charging system had 14 magnets.
The number of diodes I would have had to make a rectifier with put me
off. I didn't know what the effect of all the forward voltage drops
would be, but probably not good.

Jordan

On 8/24/2010 2:11 AM, Existential Angst wrote:

- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....

Everything is worth considering.
I think the improvement in ripple is not very big, going from 3 to 4
phases. Between 1 and 3 ph, it's a big improvement.

Jordan

On Aug 23, 8:03*pm, Jordan wrote:
On 8/24/2010 2:11 AM, Existential Angst wrote:



- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better? *
Seriously, tho....

Everything is worth considering.
I think the improvement in ripple is not very big, going from 3 to 4
phases. Between 1 and 3 ph, it's a big improvement.

Jordan

Going from single phase to two phase (polyphase actually) is the Big
improvement. Any polyphase systme can be converted to another
polyphase system. IOW, a two phase system can provide 3,4,5,6,.....
phase power.And the inverse is true too.

"Joe AutoDrill" wrote in message
news
Bob,

Just to paly devil's advocate here... Everyone is busting on you for
saying you have a 5 HP, single phase motor that draws 20 amps on your
compressor.

Fair enough. Its "says" it is 5HP on the data plate. The thing is you
don't need even that much power for a lot of milling jobs. Heck there are
lots of routers out there that claim over 3HP and they will eat through
aluminum plate almost as fast as hard wood. There are plenty of 220V
milling machines and mill drills out there claim less. In spite of getting
my chops thoroughly busted over the secondary reference the actual question
did also get answered.

And to also play Devil's advocate there are 30 AMP 110V circuits. Hundreds
of them in a big RV park. Heck, there is one on the side of my shop for my
dad's fifth wheel when he visits for the holidays. Now you guys got me
wanting to run out to the shop and double check... and I'm the one who put
that circuit in. LOL.

I have gotten used to that on this group. As long as the main questions
gets answered its all good.

Jest about 4 - there is some.

But poly phase - 9 phase and 12 - then the "twisted sisters" if you wish -
those with out of phase windings at the tips of the Star legs. Might be
several.

Industrial machines can be complex due to various needs.
They won't pay for the funny power unless they really needed it.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Originator & Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/

On 8/23/2010 11:11 AM, Existential Angst wrote:
"Pete wrote in message
ter.com...

Bob La Londe wrote:

Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V. It draw close to 20 amps on startup, but...

Straight single phase 220V is more than adequate for any power for most
shop
machines. There are some big machines out there, but for most shop
machines
its fine.

I can think of two possible answers.

1. Price of electricity. It was explained to me that power companies
often charged based on the peak demand of the leg drawing the most
current
at any given time. By balancing the load you can reduce your power bill.

2. Smoother operation. With the vagaries of the power supply from
many
electric companies by going 3 phase you can get a smoother operating
motor
with less variance of speed.

(I have worked in facilities with 440 and even 680 motors, but that is
a-whole-nuther conversation.)



Your "5 horse" motor isn't, 5HP is 30A+ at 120V. Pretty much all real
5HP motors are 240V or higher.

Three phase motors a

- Simpler, no start or run capacitors or centrifugal switches.
- More efficient.
- Have better low RPM torque and starting characteristics.
- Require smaller wiring due to lower currents on three wires for a
given HP than on two wires for single phase.
- Higher HP for a physical size.
- Less expensive due to their simplicity.
- More reliable.
- Can be accurately speed controlled.
- Smoother operation, less torque ripple.

Mebbe 4 phases would be even better?
Seriously, tho....

Tim Wescott writes:


6-phase: just like three phase, only with individual returns. Why?

6-phase was used in some heavy industry, specifically where the
complex had its own power plant. ISTM one of the BIG GM or Ford
locations had such: Willow Run maybe?


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On 08/23/2010 08:58 PM, David Lesher wrote:
Tim writes:


6-phase: just like three phase, only with individual returns. Why?

6-phase was used in some heavy industry, specifically where the
complex had its own power plant. ISTM one of the BIG GM or Ford
locations had such: Willow Run maybe?

It's handy if you're rectifying to DC, as the resultant DC is smoother.
As pointed out elsewhere there's magic transformers that'll do the trick.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Aug 24, 12:15*am, Tim Wescott wrote:
On 08/23/2010 08:58 PM, David Lesher wrote:

Tim *writes:

6-phase: just like three phase, only with individual returns. *Why?

6-phase was used in some heavy industry, specifically where the
complex had its own power plant. ISTM one of the BIG GM or Ford
locations had such: Willow Run maybe?

It's handy if you're rectifying to DC, as the resultant DC is smoother.
* As pointed out elsewhere there's magic transformers that'll do the trick.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details athttp://www.wescottdesign.com/actfes/actfes.html

Not too magic. If you have a transformer with delta secondaries, and
another set of windings that are star, then the three phases from the
two sets of windings are now 30 degrees apart, and taken as a set,
yield six phases.

Once you realize that, then three phase, and six phase are really the
same exact thing. Tt is a case of connecting the windings. you can
transmit six phase over three wires as three phase power, or as two
phase power, and a set of transformers can convert it into six phase
or nine phase or twelve phase or whatever you want....

Polyphase can be transmitted as any convenient number of phases, and
converted back and forth.
Three phase takes the least amount of wiring.

Then there are high voltage DC links. You can convert the power to any
phase or frequency at the other end.
A whole 'nother subject.

Errrrr . . . because HP from ordinary residential 120V, 15 amp breakers is limited to around 1.5 HP.

Bob Swinney
"Karl Townsend" wrote in message
...
On Mon, 23 Aug 2010 12:48:53 -0400, "Existential Angst"
wrote:

"Ignoramus23708" wrote in message
...
On 2010-08-23, Bob La Londe wrote:
Why are so many big milling machines 3 phase?

Its not about horsepower. I have a compressor with a 5 horse motor that
runs on 120V.

No you don't.

Yes he does.... well, 5 Sears hp...

Yep, everyone knows Sears compares to the number of Shetland ponies.

Quincy compares to the number of Clydesdales.

Karl