Ignoramus23077 wrote:
thanks to everyone for your thoughts!

Many pictures and the story in several chapters:

http://igor.chudov.com/projects/Phase-Converter/

Wow, you certainly work fast! Glad it's working so far. It looks like
you got some nice equipment at good prices, too. Your induction motors
look quite different from the ones we usually get in the UK. The
majority of our three phase motors are either the standard aluminium
TEFC motors or the older cast iron type, of which there are still many
around. Yours look somewhere in between these.

For the experts on phase convertors, I've got a couple of questions. I'm
thinking of building the kind of convertor Dan Caster was talking about,
where a small single phase motor permanently drives a larger three phase
motor through a variable belt drive. The three phase motor has two
terminals connected to the single phase supply and generates on the
third terminal, and the belt drive ratio is adjusted so that the single
phase motor draws its rated current when the phase convertor is working
at maximum output.

Now my questions. Firstly, will the quality of the three phase output be
improved if the single phase motor is larger than a typical pony motor
(e.g., 3/4 hp single phase motor and 2 1/2 hp three phase motor)? This
seems logical to me, as there is more torque applied to the shaft of the
three phase motor which can assist in generating the current which flows
from the third terminal, but it's such a complicated situation - what do
other people think? (It also happens that I can get the 3/4 hp and 2 1/2
hp motors cheaply and easily.) Secondly, would the addition of a
flywheel to the idler motor shaft (not necessarily together with the
permanent drive from the single phase motor) help balance the output?
Again, I intuitively think it would, but I'd be interested to hear the
views of others.

Best wishes,

Chris

Very interesting, but what is a phase converter used for?
Since this is alt.home.repair, do I need a 10 hp phase converter?
Just puzzled
:-)

--
Walter
www.rationality.net
-
"Ignoramus23077" wrote in message
...
thanks to everyone for your thoughts!

Many pictures and the story in several chapters:

http://igor.chudov.com/projects/Phase-Converter/

Here's the copy and paste of the text from the webpage:

MAIN PAGE

This text details how I made a 10 horsepower rotary phase converter
from $45 worth of parts that I bought from an industrial junkyard
gloriously called Pioneer Industrial Services.

At some point, after reading rec.crafts.metalworking and this
excellent article on making homemade phase converters, I became
excited about the idea of making a rotary phase converter from second
hand parts.

I spent about an hour calling around and finally found a guy Dave from
Pioneer Industrial Services, who said that he had used 3 phase
motors. He has a junkyard full of used electrical components. Here's
what I bought, and for how much.

The nice surprise was that the 10 HP motor was possible for me to
manhandle alone.

My first prototype was a simple setup with no switch at all, I simply
touched the wires to the 240V pieces of the subpanel. Click here to
see and read about the first prototype. It sucked and took a long time
to spin up, due to poor contacts. It was atrocious.

My second prototype included installation of a 50 amp circuit breaker
into the panel, hard wiring of the wires to the breaker, and use of a
Definite Purpose Contactor and a regular lamp switch to turn the
contactor on. Click here to see and read about the second
prototype. This works great, but is ugly and unfinished.

My future plans nclude making a nice carriage on little wheels for the
converter, and hiding all electricals inside safely.

WHAT I BOUGHT

I bought the following:

* 10 HP 3 phase Century motor - $40.
* 7.5 HP US Electrical Motors 3 phase motor - $20. I bought it
just in case.
* 30A heavy duty Square D single throw switch - $8.
* 50A Definite Purpose 3 wire normally open relay - $3.
* Five 535 V 92 mF capacitors the size of a vodka bottle - $5 for
all ($1 each).

Dave from Pioneer Industrial Services is highly recommended, he is
friendly and his proces are reasonable. I was able to pick everything
that I needed, from him. He is in Addison, IL.

FIRST PROTOTYPE

The very first try was quite simple. I spun the motor by hand and
then applied power. No capacitors. The motor was finally able to
accelerate, after much difficulty. That proved to me that it was not
"fried".

My first prototype was simply a test of the concept -- would a three
phase motor spin up like they say, if I apply capacitance between one
power leg and the generated leg?

I wired the motor as follows: two legs of 240V were connected to the
two legs of the motor. These I call Leg 1 and Leg 2. Leg 3 was
connected to Leg 1 via three capacitors wirted in parallel. You can
see that on pictures.

That made the motor spin up reliably, but slowly due to very poor
contact between my wires and the subpanel. After that, I decided to
try better wiring. See next chapter.

SECOND PROTOTYPE

Since the concept obviously worked, I now wanted to go a little bit
farther and wire it more properly.

I wired it as follows. I installed a 50 A crcuit breaker in the
subpanel. I hard wired the 8 gauge wires with one end into the
breaker, and another into the 3 pole definite purpose contactor.

The contactor is a neat thing that, when 110 V is applied to two
sensing contacts, with very little current drawn from 110v it closes
the big contacts for all three poles.

Legs 1 and 2 of utility 240V were connected to legs 1 and 2 of the
motor. Leg 1 (on the motor side, not on utility side) was ALSO
connected to one side of the capacitor bank. Leg 3 (the wild,
generated leg) of the 3 phase motor was connected to the other side of
the capacitor bank. That's how self starting phase converters should
be wired according to this excellent article on making homemade phase
converters

The converter now would spin up in less than a second. My next task
was to measure voltages between legs, which would be suggestive of the
actual degree of phase shift. The voltages were as follows: 256 V
utility, 239V, and 271V. I did not like it.

I then removed one 92 mF capacitor from the bank, leaving only two
capacitors with the total capacitance of 184 mF. The effect of this
was that instead of less than a second, the motor would spin up in
about one second. Not a big deal to me. The voltages now were as
follows: 256 V utility, 240V, and 260V. I decided that I should go
with two capacitors.

Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.

"Christopher Tidy" wrote in message
...
Ignoramus23077 wrote:
thanks to everyone for your thoughts!

Many pictures and the story in several chapters:
http://igor.chudov.com/projects/Phase-Converter/

Wow, you certainly work fast! Glad it's working so far. It looks like you
got some nice equipment at good prices, too. Your induction motors look
quite different from the ones we usually get in the UK. The majority of
our three phase motors are either the standard aluminium TEFC motors or
the older cast iron type, of which there are still many around. Yours look
somewhere in between these.

For the experts on phase convertors, I've got a couple of questions. I'm
thinking of building the kind of convertor Dan Caster was talking about,
where a small single phase motor permanently drives a larger three phase
motor through a variable belt drive. The three phase motor has two
terminals connected to the single phase supply and generates on the third
terminal, and the belt drive ratio is adjusted so that the single phase
motor draws its rated current when the phase convertor is working at
maximum output.

Now my questions. Firstly, will the quality of the three phase output be
improved if the single phase motor is larger than a typical pony motor
(e.g., 3/4 hp single phase motor and 2 1/2 hp three phase motor)?


No difference in the 3 phase output. The pony is needed only to provide
enough RPM of the 3 phase idler so it will spin up to its no load max RPM.
Once the idler is spinning, the pony can be disconnected.

SNIP

Secondly, would the addition of a
flywheel to the idler motor shaft (not necessarily together with the
permanent drive from the single phase motor) help balance the output?


No again, the idler RPM doesnt vary (measureably) with toolmotor load
related RPM. Actually, the flywheel hinders the idler's acceleration when
it is initiated.



Again, I intuitively think it would, but I'd be interested to hear the
views of others.

Best wishes,

Chris

"Ignoramus23077" wrote in message
...
| thanks to everyone for your thoughts!
|
| Many pictures and the story in several chapters:
|
| http://igor.chudov.com/projects/Phase-Converter/
|
SNIP

I don't know jack about RPC's, so I just ask this as a sounding board
for those among us who can verify my concern. Should your contactor have an
overload on it? The overload's job is to protect the equipment if an
overcurrent exists on any or all legs. In essence, it shuts all three
phases off even if one has shorted to ground. Your supplier will have some
or you can trade the contactor in for one that has it. Overloads come with
a holding contact that turns off power to the contactor if an element
overheats.
I know that current in one leg will be lower in an RPC, but as long as
it doesn't exceed the overload element's rating it will work just fine.

Yep, Carl is right about the protection considerations.

The overload protection devices aren't just to protect against the motor
developing a short to ground, they react to protect the motor from being
overloaded by a jam or machine malfunction/breakage, stalled or any other
condition that causes the current to rise to a point where the motor would
be damaged/destroyed by the resulting heat in the windings.
The OLP's heaters are selected from a chart of currents for the specific
motor being used.
Some OLPs have adjustable trip settings so that heaters don't need to be
selected.
Each type of OLP will cause all 3 phases to be opened/interrupted.

The OLPs are also available as a separate device, but are commonly
integrated into the overall starter/contactor box.

The best setup for an RPC would be a magnetic starter/OLP rated for the size
of the RPC motor, and a separate (specifically sized) starter/OLP for each
machine motor that's powered from the RPC.
Choosing not to use a second, separate OLP for the (usually) smaller machine
motor will not offer any protection for the machine motor.

WB
.................

"carl mciver" wrote in message
ink.net...

I don't know jack about RPC's, so I just ask this as a sounding board
for those among us who can verify my concern. Should your contactor have
an
overload on it? The overload's job is to protect the equipment if an
overcurrent exists on any or all legs. In essence, it shuts all three
phases off even if one has shorted to ground. Your supplier will have
some
or you can trade the contactor in for one that has it. Overloads come
with
a holding contact that turns off power to the contactor if an element
overheats.
I know that current in one leg will be lower in an RPC, but as long as
it doesn't exceed the overload element's rating it will work just fine.





----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Ignoramus23077 wrote:
thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.

On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:

Ignoramus23077 wrote:
thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:

Ignoramus23077 wrote:
thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.

Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

Gunner wrote:
On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.


Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

That site is pretty disturbing. What kind guys build those machines? I
thought metalworking was a nice, innocent hobby :-).

Incindentally, those trolls don't think like engineers. Why spend
hundreds of bucks building something with your Kmart tools when you
could just rent a jackhammer for a day?

Chris

On Thu, 28 Jul 2005 16:17:58 +0000 (UTC), Christopher Tidy
wrote:

Gunner wrote:
On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.


Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

That site is pretty disturbing. What kind guys build those machines? I
thought metalworking was a nice, innocent hobby :-).

They are for that special woman..the gift that keeps on giving G

Incindentally, those trolls don't think like engineers. Why spend
hundreds of bucks building something with your Kmart tools when you
could just rent a jackhammer for a day?

Chris

Gunner


Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

"Gunner" wrote in message ...
Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

"To announce that there must be no criticism of the president,
or that we are to stand by the president right or wrong, is not
only unpatriotic and servile, but is morally treasonable to the
American public." -- Theodore Roosevelt

Gooney wrote:
On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.


Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Great pic of your wife there Gooney.


Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

Gooney,

When you're finished blowing Ingnorant, take a course in anger mgmt.
You seem very disturbed about something.

G Henslee wrote:
Gooney wrote:

On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair,
tried it out yourself and we'd never hear from you again. Think
about it for your next project.



Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php


Great pic of your wife there Gooney.


Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

Gunner

Liberals - Cosmopolitan critics, men who are the friends of every
country save their own. Benjamin Disraeli


Gooney,

When you're finished blowing Ingnorant, take a course in anger mgmt. You
seem very disturbed about something.

Er, it would appear to be you who started this, not Gunner?

Chris

On Thu, 28 Jul 2005 16:38:54 +0000 (UTC), Christopher Tidy
wrote:

G Henslee wrote:
Gooney wrote:

On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair,
tried it out yourself and we'd never hear from you again. Think
about it for your next project.



Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php


Great pic of your wife there Gooney.


Im sure you can, with your Kmart tools, manage to find a device simple
enough for even you to build, to **** yourself with.

Gunner

Liberals - Cosmopolitan critics, men who are the friends of every
country save their own. Benjamin Disraeli


Gooney,

When you're finished blowing Ingnorant, take a course in anger mgmt. You
seem very disturbed about something.

Er, it would appear to be you who started this, not Gunner?

Chris

He is just ****ed that he got bitch slapped.

Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

On Thu, 28 Jul 2005 09:37:44 -0700, G Henslee
wrote:

Gooney wrote:
On Thu, 28 Jul 2005 06:59:20 -0700, G Henslee
wrote:


Ignoramus23077 wrote:

thanks to everyone for your thoughts!


No problem. Glad to share.


Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.


Hey Ignorant, for $10 more you could have built an electric chair, tried
it out yourself and we'd never hear from you again. Think about it for
your next project.


Hey Gomer, why not putz off? While you are mucking around, dazed look
on your face, tongue sticking out the corner of your drooling mouth,
trying to figure out how to change a drawer pull, folks like Iggy are
making the drawer pulls from scratch.

Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Great pic of your wife there Gooney.

Glad you liked it. So how about posting a picture of your husband?


Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

Goonie wrote:
On Thu, 28 Jul 2005 09:37:44 -0700, G Henslee
wrote:



Tell you what..why not go play he
http://www.****ingmachines.com/menu.php

Great pic of your wife there Gooney.


Glad you liked it. So how about posting a picture of your husband?


Goonie


Fetch fido. Here boy...

Arright, good to hear it.

John

In article , Ignoramus23077 says...

thanks to everyone for your thoughts!


Of course it works. It's physics, it *has* to work.

Good that you installed the drop-out contactor.

BTW you absolutely have to have safety glasses on the
small fry in the shop, at all times. Even when power
tools are not in use. Have a special pair just for them,
and make it a bright-line rule that they be worn.

Never too early to start 'em!

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"Ignoramus23077" wrote in message
...
thanks to everyone for your thoughts!

Many pictures and the story in several chapters:

http://igor.chudov.com/projects/Phase-Converter/

Here's the copy and paste of the text from the webpage:

MAIN PAGE

This text details how I made a 10 horsepower rotary phase converter
from $45 worth of parts that I bought from an industrial junkyard
gloriously called Pioneer Industrial Services.

At some point, after reading rec.crafts.metalworking and this
excellent article on making homemade phase converters, I became
excited about the idea of making a rotary phase converter from second
hand parts.

I spent about an hour calling around and finally found a guy Dave from
Pioneer Industrial Services, who said that he had used 3 phase
motors. He has a junkyard full of used electrical components. Here's
what I bought, and for how much.

The nice surprise was that the 10 HP motor was possible for me to
manhandle alone.

My first prototype was a simple setup with no switch at all, I simply
touched the wires to the 240V pieces of the subpanel. Click here to
see and read about the first prototype. It sucked and took a long time
to spin up, due to poor contacts. It was atrocious.

My second prototype included installation of a 50 amp circuit breaker
into the panel, hard wiring of the wires to the breaker, and use of a
Definite Purpose Contactor and a regular lamp switch to turn the
contactor on. Click here to see and read about the second
prototype. This works great, but is ugly and unfinished.

My future plans nclude making a nice carriage on little wheels for the
converter, and hiding all electricals inside safely.

WHAT I BOUGHT

I bought the following:

* 10 HP 3 phase Century motor - $40.
* 7.5 HP US Electrical Motors 3 phase motor - $20. I bought it
just in case.
* 30A heavy duty Square D single throw switch - $8.
* 50A Definite Purpose 3 wire normally open relay - $3.
* Five 535 V 92 mF capacitors the size of a vodka bottle - $5 for
all ($1 each).

Dave from Pioneer Industrial Services is highly recommended, he is
friendly and his proces are reasonable. I was able to pick everything
that I needed, from him. He is in Addison, IL.

FIRST PROTOTYPE

The very first try was quite simple. I spun the motor by hand and
then applied power. No capacitors. The motor was finally able to
accelerate, after much difficulty. That proved to me that it was not
"fried".

My first prototype was simply a test of the concept -- would a three
phase motor spin up like they say, if I apply capacitance between one
power leg and the generated leg?

I wired the motor as follows: two legs of 240V were connected to the
two legs of the motor. These I call Leg 1 and Leg 2. Leg 3 was
connected to Leg 1 via three capacitors wirted in parallel. You can
see that on pictures.

That made the motor spin up reliably, but slowly due to very poor
contact between my wires and the subpanel. After that, I decided to
try better wiring. See next chapter.

SECOND PROTOTYPE

Since the concept obviously worked, I now wanted to go a little bit
farther and wire it more properly.

I wired it as follows. I installed a 50 A crcuit breaker in the
subpanel. I hard wired the 8 gauge wires with one end into the
breaker, and another into the 3 pole definite purpose contactor.

The contactor is a neat thing that, when 110 V is applied to two
sensing contacts, with very little current drawn from 110v it closes
the big contacts for all three poles.

Legs 1 and 2 of utility 240V were connected to legs 1 and 2 of the
motor. Leg 1 (on the motor side, not on utility side) was ALSO
connected to one side of the capacitor bank. Leg 3 (the wild,
generated leg) of the 3 phase motor was connected to the other side of
the capacitor bank. That's how self starting phase converters should
be wired according to this excellent article on making homemade phase
converters

The converter now would spin up in less than a second. My next task
was to measure voltages between legs, which would be suggestive of the
actual degree of phase shift. The voltages were as follows: 256 V
utility, 239V, and 271V. I did not like it.

I then removed one 92 mF capacitor from the bank, leaving only two
capacitors with the total capacitance of 184 mF. The effect of this
was that instead of less than a second, the motor would spin up in
about one second. Not a big deal to me. The voltages now were as
follows: 256 V utility, 240V, and 260V. I decided that I should go
with two capacitors.

Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.

It looks like you're only using 1 contactor to switch the incoming lines,
right? If that's the case, your converter will be imbalanced because, in
order to start the RPC motor quickly, you have a large amount of capacitance
permanently connected between L1 and L3. The correct way to wire it is using
a start contactor to switch a big capacitor between L1 and L3 and have
permanently connected smaller capacitors between L1 and L3 and also between
L2 and L3 to balance the converter. I also agree with the other posters, use
a No Volts Release circuit using a start and stop button and the spare or
auxiliary contact on the main contactor to hold it in. Well done on getting
the parts so cheap, those caps must be worth $40 a piece.
Martin

--
martindot herewhybrowat herentlworlddot herecom

Is there any way that I can rig up a phase converter such as shown below,
and attach another power source (read gas or diesel engine) to the actual
rotor, and come out with quality 3 phase eclectic power of 60 Hz?

thanks
"Ignoramus23077" wrote in message
...
thanks to everyone for your thoughts!

Many pictures and the story in several chapters:

http://igor.chudov.com/projects/Phase-Converter/

Here's the copy and paste of the text from the webpage:

MAIN PAGE

This text details how I made a 10 horsepower rotary phase converter
from $45 worth of parts that I bought from an industrial junkyard
gloriously called Pioneer Industrial Services.

At some point, after reading rec.crafts.metalworking and this
excellent article on making homemade phase converters, I became
excited about the idea of making a rotary phase converter from second
hand parts.

I spent about an hour calling around and finally found a guy Dave from
Pioneer Industrial Services, who said that he had used 3 phase
motors. He has a junkyard full of used electrical components. Here's
what I bought, and for how much.

The nice surprise was that the 10 HP motor was possible for me to
manhandle alone.

My first prototype was a simple setup with no switch at all, I simply
touched the wires to the 240V pieces of the subpanel. Click here to
see and read about the first prototype. It sucked and took a long time
to spin up, due to poor contacts. It was atrocious.

My second prototype included installation of a 50 amp circuit breaker
into the panel, hard wiring of the wires to the breaker, and use of a
Definite Purpose Contactor and a regular lamp switch to turn the
contactor on. Click here to see and read about the second
prototype. This works great, but is ugly and unfinished.

My future plans nclude making a nice carriage on little wheels for the
converter, and hiding all electricals inside safely.

WHAT I BOUGHT

I bought the following:

* 10 HP 3 phase Century motor - $40.
* 7.5 HP US Electrical Motors 3 phase motor - $20. I bought it
just in case.
* 30A heavy duty Square D single throw switch - $8.
* 50A Definite Purpose 3 wire normally open relay - $3.
* Five 535 V 92 mF capacitors the size of a vodka bottle - $5 for
all ($1 each).

Dave from Pioneer Industrial Services is highly recommended, he is
friendly and his proces are reasonable. I was able to pick everything
that I needed, from him. He is in Addison, IL.

FIRST PROTOTYPE

The very first try was quite simple. I spun the motor by hand and
then applied power. No capacitors. The motor was finally able to
accelerate, after much difficulty. That proved to me that it was not
"fried".

My first prototype was simply a test of the concept -- would a three
phase motor spin up like they say, if I apply capacitance between one
power leg and the generated leg?

I wired the motor as follows: two legs of 240V were connected to the
two legs of the motor. These I call Leg 1 and Leg 2. Leg 3 was
connected to Leg 1 via three capacitors wirted in parallel. You can
see that on pictures.

That made the motor spin up reliably, but slowly due to very poor
contact between my wires and the subpanel. After that, I decided to
try better wiring. See next chapter.

SECOND PROTOTYPE

Since the concept obviously worked, I now wanted to go a little bit
farther and wire it more properly.

I wired it as follows. I installed a 50 A crcuit breaker in the
subpanel. I hard wired the 8 gauge wires with one end into the
breaker, and another into the 3 pole definite purpose contactor.

The contactor is a neat thing that, when 110 V is applied to two
sensing contacts, with very little current drawn from 110v it closes
the big contacts for all three poles.

Legs 1 and 2 of utility 240V were connected to legs 1 and 2 of the
motor. Leg 1 (on the motor side, not on utility side) was ALSO
connected to one side of the capacitor bank. Leg 3 (the wild,
generated leg) of the 3 phase motor was connected to the other side of
the capacitor bank. That's how self starting phase converters should
be wired according to this excellent article on making homemade phase
converters

The converter now would spin up in less than a second. My next task
was to measure voltages between legs, which would be suggestive of the
actual degree of phase shift. The voltages were as follows: 256 V
utility, 239V, and 271V. I did not like it.

I then removed one 92 mF capacitor from the bank, leaving only two
capacitors with the total capacitance of 184 mF. The effect of this
was that instead of less than a second, the motor would spin up in
about one second. Not a big deal to me. The voltages now were as
follows: 256 V utility, 240V, and 260V. I decided that I should go
with two capacitors.

Costs of parts actually used, so far:

* 10 HP motor -- $40
* Definite Purpose contactor -- $3
* 2 capacitors, 92 mF each -- $2

The total cost, so far, is $45. Wires and new breaker do not count.

The amount of current that an induction motor draws depends on the
amount of power being produced. A motor that has no load does not draw
nearly as much current as one producing the horsepower listed on the
nameplate. The neat thing is that if you put a little power into the
motor it will draw even less current. More power in and the current
drawn goes negative......That is the motor is generating electricity.

Note while an induction motor can be made to generate power when it is
not hooked to the power grid, it requires some capacitors to do so and
will not work well over a wide range of power out. But if one attaches
another power source to the rotor and have single phase power connected
to two of the wires, it will produce quality 3 phase power of 60 hz (
assuming 60 hz single phase power ). Can even be driven with a single
phase electric motor, but must be driven at slightly over the
synchronous speed ( 1800 rpm for a 4 pole motor ).
So if doing this with a electric motor you need to belt drive and have
one of the pulleys adjustable. Then measure the current drawn by the
single phase motor and adjust the pulley ratio so that the current
drawn by the single phase motor is within its rated nameplate current .

You can also use a induction motor driven with a gas engine to keep the
rpms at a constant amount. This is used with the gasolene engines with
variable compression ratio used to test octane of gasolene.

Dan


The Tagge's wrote:
Is there any way that I can rig up a phase converter such as shown below,
and attach another power source (read gas or diesel engine) to the actual
rotor, and come out with quality 3 phase eclectic power of 60 Hz?

thanks