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Induction Motor Design

G

Gary Pace

Jan 1, 1970
0
Howdy Y'all :

Somewhat OT.

I am going to start designing induction motors (flux density, rotor bars,
pole faces, stator slots, insulation systems etc etc) up to a few MW at
various voltages and frequencies

I've been controlling them for decades, so I know a bit about this.

Does anyone know :

- Any good books on this subject
- A better newsgroup to ask

Thanks
Gary
 
K

Ken Smith

Jan 1, 1970
0
Gary Pace said:
I am going to start designing induction motors (flux density, rotor bars,
pole faces, stator slots, insulation systems etc etc) up to a few MW at
various voltages and frequencies

Tesla's works comes to mind :)

You could try googling on XBR and induction motor. You may find the
information you need is on line at some university.
 
Gary said:
Howdy Y'all :

Somewhat OT.

I am going to start designing induction motors (flux density, rotor bars,
pole faces, stator slots, insulation systems etc etc) up to a few MW at
various voltages and frequencies

I've been controlling them for decades, so I know a bit about this.

Does anyone know :

- Any good books on this subject
- A better newsgroup to ask

Thanks
Gary
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D

Don Lancaster

Jan 1, 1970
0
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See the ads in Appliance, Appliance New Product Digest, and Appliance
Designer magazines.


--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
S

Spehro Pefhany

Jan 1, 1970
0
Howdy Y'all :

Somewhat OT.

I am going to start designing induction motors (flux density, rotor bars,
pole faces, stator slots, insulation systems etc etc) up to a few MW at
various voltages and frequencies

I've been controlling them for decades, so I know a bit about this.

Does anyone know :

- Any good books on this subject
- A better newsgroup to ask

Thanks
Gary

A quick search finds:

THE INDUCTION MOTOR. ITS THEORY AND DESIGN SET FORTH BY A PRACTICAL
METHOD OF CALCULATION. Translation from the French by C. O. Mailloux.
De La Tour, Henry Boy. NY: McGraw, 1903


THE PERFORMANCE AND DESIGN OF ALTERNATING CURRENT MACHINES:
Transformers, Three-phase Induction Motors and Synchronous Machines.
M.G.SAY. London. Sir Isaac Pitman & Sons Ltd. 1948.

Induction Machines: Their Behavior and Uses
by Philip L. Alger (first published in 1970)

All those are pre-computer modelling--
more modern work undoubtedly uses computer modelling extensively,
along with a whole bunch of proprietary and empirical knowlege. The
IEEE IEMDC conference proceedings and vendor list would be a good
starting point for access to products and papers in that area. Most
recent one was in San Antonio, TX (USA) in May 2005.

But the fastest way to learn in this area is probably to get a job in
a company that already does this, which I assume is what you've done,
unless your post is a troll.


Best regards,
Spehro Pefhany
 
G

Glen Walpert

Jan 1, 1970
0
Howdy Y'all :

Somewhat OT.

I am going to start designing induction motors (flux density, rotor bars,
pole faces, stator slots, insulation systems etc etc) up to a few MW at
various voltages and frequencies

I've been controlling them for decades, so I know a bit about this.

Does anyone know :

- Any good books on this subject
- A better newsgroup to ask

Thanks
Gary

Induction motors are infrequently used in the few MW size range where
the advantages of synchronous machines are generally significant, but
they do have their applications. In these larger sizes it is common
to design and build to suit a specific application, normally done by
the engineering departments of the few large companies which build
motors of these sizes, by a team of experienced mechanical and
electrical engineers whom I would expect to be using the latest and
greatest in finite element analysis software to deal with the immense
complexity of the interrelated thermal, mechanical and electrical
issues.

Taking a wild guess that you will be tweaking existing standard
designs for some smaller mfgr or merely specifying what exactly you
want from a larger mfgr, and assuming you have already read NEMA MG-1,
IEEE 115 and the rest of the common motor standards, and that you have
a solid understanding of the basic theory which is probably still best
explained in Principles of Alternating Current Machinery by Lawrence
and Richards (4th ed, 1953) and the generic info in the McGraw Hill
Electric Motor Handbook, then you might want to read Analysis of
Electrical Machines by Richard Smith.

If your motors will be powered by inverters also look at the new
induction motor design by Chorus Motors, which triples low speed
torque compared to a standard 3 phase design in the same frame size.

http://www.chorusmotors.gi/
 
D

Don Lancaster

Jan 1, 1970
0
Spehro said:
A quick search finds:

THE INDUCTION MOTOR. ITS THEORY AND DESIGN SET FORTH BY A PRACTICAL
METHOD OF CALCULATION. Translation from the French by C. O. Mailloux.
De La Tour, Henry Boy. NY: McGraw, 1903


THE PERFORMANCE AND DESIGN OF ALTERNATING CURRENT MACHINES:
Transformers, Three-phase Induction Motors and Synchronous Machines.
M.G.SAY. London. Sir Isaac Pitman & Sons Ltd. 1948.

Induction Machines: Their Behavior and Uses
by Philip L. Alger (first published in 1970)

All those are pre-computer modelling--
more modern work undoubtedly uses computer modelling extensively,
along with a whole bunch of proprietary and empirical knowlege. The
IEEE IEMDC conference proceedings and vendor list would be a good
starting point for access to products and papers in that area. Most
recent one was in San Antonio, TX (USA) in May 2005.

But the fastest way to learn in this area is probably to get a job in
a company that already does this, which I assume is what you've done,
unless your post is a troll.


Best regards,
Spehro Pefhany

Actually, induction motors are horribly obsolete.

Because of their difficulty of single phase starting, lousy power factor
energy inefficiency, and difficult/limited speed control.

Virtually all newer designs are going switched reluctance instead.
The challenges today lie in the cogging and stability algorithms.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
G

Glen Walpert

Jan 1, 1970
0
Actually, induction motors are horribly obsolete.

Because of their difficulty of single phase starting, lousy power factor
energy inefficiency, and difficult/limited speed control.

Virtually all newer designs are going switched reluctance instead.
The challenges today lie in the cogging and stability algorithms.

I assume you are talking about small single phase motors such as the
appliance motors you refered to earlier. Does anyone make MW sized
(well over 1000 HP) 3-phase switched reluctance motors, or is there
any reason someone might want to?
 
G

Gary Pace

Jan 1, 1970
0
Spehro Pefhany said:
A quick search finds:

THE INDUCTION MOTOR. ITS THEORY AND DESIGN SET FORTH BY A PRACTICAL
METHOD OF CALCULATION. Translation from the French by C. O. Mailloux.
De La Tour, Henry Boy. NY: McGraw, 1903


THE PERFORMANCE AND DESIGN OF ALTERNATING CURRENT MACHINES:
Transformers, Three-phase Induction Motors and Synchronous Machines.
M.G.SAY. London. Sir Isaac Pitman & Sons Ltd. 1948.

Induction Machines: Their Behavior and Uses
by Philip L. Alger (first published in 1970)

All those are pre-computer modelling--
more modern work undoubtedly uses computer modelling extensively,
along with a whole bunch of proprietary and empirical knowlege. The
IEEE IEMDC conference proceedings and vendor list would be a good
starting point for access to products and papers in that area. Most
recent one was in San Antonio, TX (USA) in May 2005.

But the fastest way to learn in this area is probably to get a job in
a company that already does this, which I assume is what you've done,
unless your post is a troll.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
[email protected] Info for manufacturers:
http://www.trexon.com
Embedded software/hardware/analog Info for designers:
http://www.speff.com

Thanks - I'll try to get copies of these.
 
G

Gary Pace

Jan 1, 1970
0
Don Lancaster said:
Actually, induction motors are horribly obsolete.

Because of their difficulty of single phase starting, lousy power factor
energy inefficiency, and difficult/limited speed control.

Virtually all newer designs are going switched reluctance instead.
The challenges today lie in the cogging and stability algorithms.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

There are certainly alternative motor technologies that have advantages over
the induction motor, I don't think you can say they're obsolete - mature
would be a better word. The issues of starting and power factor mainly apply
to DOL situations. What other motor technology can connect DOL in any
circumstance ?

SR motors have advantages of cheap and robust construction, but present
control problems of their own especially in wide speed range torque
controlled applications.

DC machines are a very easy control proposition (cheap and robust SCR's),
but the (somewhat over-blown) issue of comm/brush maintenance has made them
increasingly unpopular.

Synchronous motors have higher power densities and are easy to control. PM
machines are problematic to control in field weakening, and sep.ex. motors
bring back brushes (or extra windings). These are typically expensive
machines.

My experience has been that for most low voltage (or low-end medium voltage)
applications below a few MW, a voltage-source inverter (with v/hz control,
vector control or direct torque control) and an induction motor is always a
good technical and economic candidate.
 
G

Gary Pace

Jan 1, 1970
0
Glen Walpert said:
Induction motors are infrequently used in the few MW size range where
the advantages of synchronous machines are generally significant, but
they do have their applications. In these larger sizes it is common
to design and build to suit a specific application, normally done by
the engineering departments of the few large companies which build
motors of these sizes, by a team of experienced mechanical and
electrical engineers whom I would expect to be using the latest and
greatest in finite element analysis software to deal with the immense
complexity of the interrelated thermal, mechanical and electrical
issues.

Taking a wild guess that you will be tweaking existing standard
designs for some smaller mfgr or merely specifying what exactly you
want from a larger mfgr, and assuming you have already read NEMA MG-1,
IEEE 115 and the rest of the common motor standards, and that you have
a solid understanding of the basic theory which is probably still best
explained in Principles of Alternating Current Machinery by Lawrence
and Richards (4th ed, 1953) and the generic info in the McGraw Hill
Electric Motor Handbook, then you might want to read Analysis of
Electrical Machines by Richard Smith.

If your motors will be powered by inverters also look at the new
induction motor design by Chorus Motors, which triples low speed
torque compared to a standard 3 phase design in the same frame size.

http://www.chorusmotors.gi/

Glen :
Thanks for your reply. I will get copies of all the spec's and books you
recommend. No - these are brand new atypical designs.

From reading the various replies to my original post, I received the
impression that folks thought it was a troll post (whatever that means) - so
here's the background (in case anybody's interested)

We are a manufacturer of motors and drives. I design the drives (IGBT's,
DSP's, software, FPGA's, motor control algorithm - all that stuff) and to
me, the motors have always been an equivalent circuit with saturation,
leakage, resistance etc etc
The electro-magnetics of our motors have typically been designed elsewhere,
and we've just designed the cooling, selected the bearings, stacked
laminates, wound coils, pressed in rotor bars, VPI'ed them...etc etc
This is an increasing problem (why is it too hot? why's the power factor bad
?...) so we have decided to find out if we can learn to design motors
ourselves in a reasonable amount of time.

Maybe I'll conclude that this is a whole career's work - in which case my
next post may well be "who is the best consultant to design the
electro-magnetics of our motors"
Gary
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
Induction motors are infrequently used in the few MW size range where
the advantages of synchronous machines are generally significant, but
they do have their applications. In these larger sizes it is common
to design and build to suit a specific application, normally done by
the engineering departments of the few large companies which build
motors of these sizes, by a team of experienced mechanical and
electrical engineers whom I would expect to be using the latest and
greatest in finite element analysis software to deal with the immense
complexity of the interrelated thermal, mechanical and electrical
issues.

I have on occasion seen ABB design motors to some customer spec. What they
use is a software application that basically generate the input to the
mostly robotic factories; and of course generate build-orders to the factory
workers that assemble the large machines. You get the delivery schedule
documentation and everything of that sort in less than an hour.

It is a *very* mature business.

PS:

Outside the staff cafeteria in Vesteras, Sweden, there is a motor the size
of a caravan. The point is that it does not run - but is was built exactly
according to the specifications entered into the robotic factory ;-).
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
From reading the various replies to my original post, I received the
impression that folks thought it was a troll post (whatever that means) - so
here's the background (in case anybody's interested)

We are a manufacturer of motors and drives. I design the drives (IGBT's,
DSP's, software, FPGA's, motor control algorithm - all that stuff) and to
me, the motors have always been an equivalent circuit with saturation,
leakage, resistance etc etc
The electro-magnetics of our motors have typically been designed elsewhere,
and we've just designed the cooling, selected the bearings, stacked
laminates, wound coils, pressed in rotor bars, VPI'ed them...etc etc
This is an increasing problem (why is it too hot? why's the power factor bad
?...) so we have decided to find out if we can learn to design motors
ourselves in a reasonable amount of time.

Easy: You are not good enough at building motors ;-)

If this is just reasonably standard stuff, why not just drop it and buy the
whole thing assembled, tested and ready from one of the large manufacturers?
Maybe I'll conclude that this is a whole career's work - in which case my
next post may well be "who is the best consultant to design the
electro-magnetics of our motors"

The motor business is so mature that, I.M.O., there is no way to do better
than the COTS stuff.
 
T

Terry Given

Jan 1, 1970
0
Frithiof said:
Easy: You are not good enough at building motors ;-)

If this is just reasonably standard stuff, why not just drop it and buy the
whole thing assembled, tested and ready from one of the large manufacturers?




The motor business is so mature that, I.M.O., there is no way to do better
than the COTS stuff.

the bvest way to learn how to do this is by secondment. get your boss to
pay you to take a job at, say, WEG, and learn as much as possible. it'll
be heaps faster. Or better yet, approach a senior motor designer at one
of these companies, and hire him (or her, but odds on its a him).

Cheers
Terry
 
K

Ken Smith

Jan 1, 1970
0
of a caravan. The point is that it does not run - but is was built exactly
according to the specifications entered into the robotic factory ;-).

Um, do you mean, "Caravan", as in "Dodge Caravan", the SUV, or do you
mean it's as big as a string of camels and stuff across the desert?[/QUOTE]

I think he means what an American would call a "motor home".
And, the more important question - _would_ it run, if pressed into
service? It's true, there are considerations when scaling stuff, but
I've seen pictures of HUGE hydroelectric generators - why not a HUGE
motor?

It could also be that they applied power too it once and the result was a
lot of smoke.
 
G

Glen Walpert

Jan 1, 1970
0
Glen :
Thanks for your reply. I will get copies of all the spec's and books you
recommend. No - these are brand new atypical designs.

Check that those specs actually apply to you first, MG-1 defines
standard sizes, ratings, insulation classes etc. and IEEE Std 115 is
motor and generator testing standards per my decade old recollection,
but these are US standards which may or may not apply to you.

The McGraw-Hill handbook is probably more useful to motor users than
designers.

I first read Lawrence when an electrical designer taking an AC
machines course at Drexel University gave me a copy about 15 years
ago. His professor, whose day job was designing custom substation
transformers, handed them out as textbooks for the course, claiming
that it was written by the people who first developed rigorous AC
machine theory at MIT, and that nothing written since is nearly as
good. I liked it so much I bought used copies of both the first
(1916) and fourth (1953) editions, which present an intersting view of
AC machine theory development over that period.

Smith goes beyond Lawrence in presenting useful induction motor design
theory, taking the approach of "reflecting" (his terminology) stator
and rotor currents as well as copper and iron losses "into the air
gap", or expressing everything in terms of the air gap magnetic field.
I intended to use his equations as the starting point of a motor model
a few years ago when I thought I would have time to model the 18 phase
Chorus design and have one wound on a standard 36-slot frame, but
other priorities have pushed that project somewhere behind the back
burner.

Books are cheap, why not look into the one Sphero recommended too.
From reading the various replies to my original post, I received the
impression that folks thought it was a troll post (whatever that means) - so
here's the background (in case anybody's interested)

You are obviously new here. A troll post is usually something like
posting 101 things to do with a dead cat to a cat lovers group, but on
this group any question from an unknown poster which does not include
a schematic, part numbers, design calculations and measurements
contradicting those calculations is considered by some to be a troll,
inciting a blast delivered in the same spirit as the cat recipe post
:).
We are a manufacturer of motors and drives. I design the drives (IGBT's,
DSP's, software, FPGA's, motor control algorithm - all that stuff) and to
me, the motors have always been an equivalent circuit with saturation,
leakage, resistance etc etc
The electro-magnetics of our motors have typically been designed elsewhere,
and we've just designed the cooling, selected the bearings, stacked
laminates, wound coils, pressed in rotor bars, VPI'ed them...etc etc
This is an increasing problem (why is it too hot? why's the power factor bad
?...) so we have decided to find out if we can learn to design motors
ourselves in a reasonable amount of time.

Maybe I'll conclude that this is a whole career's work - in which case my
next post may well be "who is the best consultant to design the
electro-magnetics of our motors"
Gary

Interesting stuff indeed. An alternate question you might ask is who
is the best consultant to hire to help get you and your company up to
speed on motor magnetics modeling and design. This NG might not be
the best place for that question, but the professors who teach AC
machines at the few universities which still have a decent power
program in their EE department might be a good source of leads. I
don't know if MIT still does power or not, but if so they might have
their AC machines course available on line too.

BTW I have never designed a motor (although I have tested a bunch of
them), just find the subject entertaining. Don't treat my posts as
authoritative but as just a bunch of top of the head ideas for you to
think about.

Regards,
Glen
 
D

Don Lancaster

Jan 1, 1970
0
Ken said:
Um, do you mean, "Caravan", as in "Dodge Caravan", the SUV, or do you
mean it's as big as a string of camels and stuff across the desert?


I think he means what an American would call a "motor home".

And, the more important question - _would_ it run, if pressed into
service? It's true, there are considerations when scaling stuff, but
I've seen pictures of HUGE hydroelectric generators - why not a HUGE
motor?


It could also be that they applied power too it once and the result was a
lot of smoke.
[/QUOTE]

All electronic components run on smoke.
If you let the smoke out, they do not work any more.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
Rich said:
Um, do you mean, "Caravan", as in "Dodge Caravan", the SUV, or do you
mean it's as big as a string of camels and stuff across the desert?
;-)

The box some people drag after their cars the entire summer holiday - mostly
to create rolling road-blocks and annoy the hell out of motorists.
And, the more important question - _would_ it run, if pressed into
service? It's true, there are considerations when scaling stuff, but
I've seen pictures of HUGE hydroelectric generators - why not a HUGE
motor?

Or is your point that robots are stupid?

Point is that - as far as I remember - the "designer" set the number of
poles in the rotor and stator wrong (equal?), so it never starts. It just
lets out a gentle hum (until the smoke signals a need of maintenance).

And that the thing went all the way through the build-process on schedule
too.
Speaking of stupid specifications, I was in on writing a transformer
spec one time for a very weird power supply - I don't remember the
exact numbers, but this tranny had two secondaries, but it was
guaranteed in the spec that only one of them would be used at any
time. I was only a tech, but I tried to explain to the PHB, "You
don't need to spec the tranny to use both secondaries simultaneously
- you could spec this thing about 33% smaller (or whatever the figure
was)" but he overrode me, ordered the oversized transformer, and when
it came in, it didn't even fit in the enclosure.

It is also guranteed that regardless of what the spec sez, the two
secondaries will be on at the same time eventually - OTOH one sells more
product that way.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Glen Walpert <[email protected]>
You are obviously new here. A troll post is usually something like
posting 101 things to do with a dead cat to a cat lovers group, but on
this group any question from an unknown poster

Well, not ANY question. The troll-detector does tend to respond to
people who post the equivalent of, 'I don't know anything about
doctoring, so please tell me which web sites show me how to be a brain
surgeon.'

Usually less well spelled and less gramatiqual.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that "Rich, Under the Affluence"
Um, do you mean, "Caravan", as in "Dodge Caravan", the SUV, or do you
mean it's as big as a string of camels and stuff across the desert?
;-)

'Caravan' is British English for 'trailer'.
And, the more important question - _would_ it run, if pressed into
service? It's true, there are considerations when scaling stuff, but
I've seen pictures of HUGE hydroelectric generators - why not a HUGE
motor?

I've been close to some 60 MW motors at a water pumping station (3300 A
at 11 kV 3-phase), quite big but I don't suppose they are the biggest.
 
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