Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

"Lloyd E. Sponenburgh" wrote:

Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

I expect the efficiency is a bit lower with multiple motors due to
accumulated losses in bearings and whatnot. The best way to go is to
eliminate the need for three phase power as much as possible and use
VFDs in the few cases where it isn't possibly. VFDs are more efficient
and also much quieter than an RPC.

You can use a series of motors to get the capacity you need. If you
want, you can do a sequenced start where one motor comes on line, use
that one to start the second, the first two to start the third and so
on. As long as the combined HP of the on line motors is significantly
more than the newest one to come online, you can just run the new one as
a pure 3 phase motor. Since you are starting them off the previous
motors, you do not need to mechanically couple them. It does make sense
to couple the first one or two to a single phase starting motor.

The downside of all this is the extra motors, extra switching, extra
space, extra noise, extra power losses, and general hassle. Used 3 phase
motors are cheap. If the windings are ok, the only thing that goes wrong
is the bearings, cheap enough to replace.

Lloyd E. Sponenburgh wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

On 2009-01-19, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

Absolutely. No need to couple them mechanically.

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

I have a phase converter with two idlers, which has a lot of benefits
and no drawbacks. My idlers are 10 and 7.5 HP respectively. Using a
lot of 1-3 HP motors would be messy, but not really electrically
infeasible.

What were you quoted on a 7.5 HP motor?

Would you be interested in a new Reliance 10 HP motor?

I do not think that in a HSM context, you need a new motor for an
idler. Even used motors have thousands of hours of service ahead of
them, and phase converter does not load the bearings with anything
besides the weight of the rotor.

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On 2009-01-19, Pete C. wrote:

"Lloyd E. Sponenburgh" wrote:

Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

I expect the efficiency is a bit lower with multiple motors due to
accumulated losses in bearings and whatnot. The best way to go is to
eliminate the need for three phase power as much as possible and use
VFDs in the few cases where it isn't possibly. VFDs are more efficient
and also much quieter than an RPC.

He cannot do it on his CNC mill.
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On Mon, 19 Jan 2009 09:13:26 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

As far as Im aware..and do this in my own HS...multiple motors simply
add to the capacity.

My big 7.5hp Clausing 1500 didnt want to start on the 5hp RPC, but Id
turn on the MasterMill and the HLVH, leave them running and the Clausing
would fire right up.

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.

Ignoramus16024 wrote:

On 2009-01-19, Pete C. wrote:

"Lloyd E. Sponenburgh" wrote:

Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

LLoyd

I expect the efficiency is a bit lower with multiple motors due to
accumulated losses in bearings and whatnot. The best way to go is to
eliminate the need for three phase power as much as possible and use
VFDs in the few cases where it isn't possibly. VFDs are more efficient
and also much quieter than an RPC.

He cannot do it on his CNC mill.

Sure he can. If he were reasonable close to Dallas I'd offer to help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.

"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.


Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

I _could_ re-design all the speed control circuitry and hardware so
that it controlled a VFD, but it's a closed-loop system as it now
exists, and it wouldn't be a simple re-work.

My goal right now is to get the machine full-up working _as_designed_,
THEN think about an upgrade or retro-fit of the electronics.

In addition to that, it will take some re-wiring anyway, because the
R2E3 and R2E4 main electronics supplies derive their power from two
phases of the 3-phase, rather than only one.

LLoyd

Gunner Asch fired this volley in
:

but Id
turn on the MasterMill and the HLVH, leave them running and the
Clausing
would fire right up.



Sure... "no load" is the operative principle, though. Both the other
machines are acting as idlers. If you loaded the first two machines,
I'll bet the third wouldn't start.

LLoyd

Ignoramus16024 fired this volley
in :

Would you be interested in a new Reliance 10 HP motor?


Might be, Iggy; How much? (and how to ship economically?)
I love the old RE designs. They last forever. I have a 1968 RE 1HP
TENV motor on a powder granulator that is still running as quiet and
strong as it did new, and it's never had _anything_ done to it.

Are the 'new' ones as beefy as the 60's vintage motors? I re-painted
the '68 one a while ago, and it weighed in at just under 90lb. A new
one on another machine (of other manufacture; I think GE) weighed
about 60.

Yes, I know I don't need 'new' motors, but I can get 3HP NEW Dayton
motors for under $50, and with aggregate shipping, about $10 apiece to
ship. I already have two (only one working as an RPC right now_), and
they work fine with my 2HP spindle motor, even though the rotating
mass on the new motors is MUCH lower than the older designs.

LLoyd

On 2009-01-19, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus16024 fired this volley
in :

Would you be interested in a new Reliance 10 HP motor?


Might be, Iggy; How much? (and how to ship economically?)
I love the old RE designs. They last forever. I have a 1968 RE 1HP
TENV motor on a powder granulator that is still running as quiet and
strong as it did new, and it's never had _anything_ done to it.

This is that sort of thing, in a cardboard crate (plywood
bottom). TEFC motor. 10 HP.

$200 plus shipping, it is UPSable. Figure about 130 lbs weight.

This motor was never unbolted from plywood.

As I said, I think that if you look and find a used super cheap 10 HP
motor, for say $40, you will be fine with it for your phase converter
application, essentially forever. And no shipping to pay if you find
locally, at some tired guy's warehouse, hidden in layers of dust and
other crap. Given current economic environment, scrap price and
general fear level, you should be able to do that.

But, if you want new, my offer will stand for a week or so.

Are the 'new' ones as beefy as the 60's vintage motors? I re-painted
the '68 one a while ago, and it weighed in at just under 90lb. A new
one on another machine (of other manufacture; I think GE) weighed
about 60.

I am pretty sure that it is over 100 lbs, with the box but the box is
not much.

Yes, I know I don't need 'new' motors, but I can get 3HP NEW Dayton
motors for under $50, and with aggregate shipping, about $10 apiece to
ship. I already have two (only one working as an RPC right now_), and
they work fine with my 2HP spindle motor, even though the rotating
mass on the new motors is MUCH lower than the older designs.

I would love to sell this motor to you, but in my honest opinion it is
overkill for what you want. Find some garbage used motors and that
will work just as well.

Just one more disclaimer, the motor I have is under a pile of stuff,
and there is a very small chance that I either do not have it, or it
is not 10 HP, but my memory is pretty good in this instance.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
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Ignoramus16024 fired this volley
in :
Just one more disclaimer, the motor I have is under a pile of stuff,
and there is a very small chance that I either do not have it, or it
is not 10 HP, but my memory is pretty good in this instance.



G Thanks, Iggy. I'll pass, partly because of the distance, and partly
because you're right -- if I really need a bigger unit, I can dig one up
locally for a good price.

LLoyd

Lloyd E. Sponenburgh wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

You'll probably have less kinetic energy stored in several small motors,
assuming they all run at the same speed. Whether this matters or not is
a subject of debate. I haven't formed an opinion on the subject, and it
doesn't seem that anyone has tried it and published the results.

There was a discussion about it at RCM a few years ago:
http://groups.google.com/group/rec.c...ba39677940455f

I am pretty sure that your phase convertor will work with either one
large idler motor or several small motors with the same total horsepower
rating. But to say that there won't be any difference at all is going
beyond the evidence we have, I think.

I'd be interested to hear what Bob has to say. Some day I may try this
experiment, and if I do I'll post the results here.

Best wishes,

Chris

On Mon, 19 Jan 2009 14:16:56 -0600, Ignoramus16024
wrote:

On 2009-01-19, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

Absolutely. No need to couple them mechanically.

That assertion certainly bespeaks authority.

On 2009-01-20, Don Foreman wrote:
On Mon, 19 Jan 2009 14:16:56 -0600, Ignoramus16024
wrote:

On 2009-01-19, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

Absolutely. No need to couple them mechanically.

That assertion certainly bespeaks authority.

So, why do you think that they need to be coupled mechanically?
--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

Ignoramus26200 fired this volley
in :

So, why do you think that they need to be coupled mechanically?


Iggy, I don't think that was the issue he was addressing.

LLoyd

Chris sez:

" . . .I am pretty sure that your phase convertor will work with either one
large idler motor or several small motors with the same total horsepower
rating. But to say that there won't be any difference at all is going
beyond the evidence we have, I think . . ."

Although I've never set up specific experiments substituting several small idlers for one large
idler I am reasonably certain the difference, if any, is miniscule. I would think accumulated
friction and windage losses from many small idlers would become objectionable only over a large
number of idlers. Not likely to be problematical in quantities used in a home shop.

Problems with differing pole arrangements and speed is a non-issue. One might consider all the
motors running in any 3-phase distribution system. Those motors, irrespective of speed, numbers of
poles, even phase, are all interchanging current with each other on some level. That analogy is
applicable to the entire grid.

Bob Swinney












"Christopher Tidy" wrote in message
...
Lloyd E. Sponenburgh wrote:
Bob, I've got a theory question I might put in practice, if I've got
the right idea.

I have built a couple of low-horse RPCs. No problems there.

As I study the "rotary transformer" theory, it seems to me that both
schematically and practically, there should be absolutely no
difference in using multiple lower-horsepower idlers than in using one
larger one; perhaps it might matter that they all have the same pole
arrangement and speed... but maybe not even then.

And it appears that there would be no benefit derived (or lost) from
coupling them mechanically.

Am I on the right track?

I hope so, as I can buy spankin' new-in-box old stock 1-3HP motors for
about 1/6th the price of NOS 5-7HP ones.

You'll probably have less kinetic energy stored in several small motors,
assuming they all run at the same speed. Whether this matters or not is
a subject of debate. I haven't formed an opinion on the subject, and it
doesn't seem that anyone has tried it and published the results.

There was a discussion about it at RCM a few years ago:
http://groups.google.com/group/rec.c...ba39677940455f


I'd be interested to hear what Bob has to say. Some day I may try this
experiment, and if I do I'll post the results here.

Best wishes,

Chris

"Robert Swinney" fired this volley in
:

Those motors, irrespective of speed, numbers of poles, even
phase, are all interchanging current with each other on some level.
That analogy is applicable to the entire grid.


Thanks, Bob. That's what I supposed, but don't have the power
distribution experience to confirm it, except empirically.

LLoyd

On Tue, 20 Jan 2009 08:16:01 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Ignoramus26200 fired this volley
in :

So, why do you think that they need to be coupled mechanically?


Iggy, I don't think that was the issue he was addressing.

LLoyd

Right!

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.


Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

I _could_ re-design all the speed control circuitry and hardware so
that it controlled a VFD, but it's a closed-loop system as it now
exists, and it wouldn't be a simple re-work.

My goal right now is to get the machine full-up working _as_designed_,
THEN think about an upgrade or retro-fit of the electronics.

In addition to that, it will take some re-wiring anyway, because the
R2E3 and R2E4 main electronics supplies derive their power from two
phases of the 3-phase, rather than only one.

LLoyd

Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

Pete C.

On 2009-01-20, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.


Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

I _could_ re-design all the speed control circuitry and hardware so
that it controlled a VFD, but it's a closed-loop system as it now
exists, and it wouldn't be a simple re-work.

My goal right now is to get the machine full-up working _as_designed_,
THEN think about an upgrade or retro-fit of the electronics.

In addition to that, it will take some re-wiring anyway, because the
R2E3 and R2E4 main electronics supplies derive their power from two
phases of the 3-phase, rather than only one.

LLoyd

Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

Pete, if I understood Lloyd right, and I think that I heard the same
thing a while ago from someone else, the BOSS controls really need all
three phases to operate. And then from then on, all control circuitry
is 220v or 110v based and thus you need extra relays and stuff just to
operate the VFDs which usually use 10v for signaling.

Easy with a phase converter, hard with drives.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

It may not be so simple because contactors may be interlocked with one
another in a way that requires 110 or 220v. (something like, the
spindle must be running in order to move table, etc)

What you say is possible, but what is also possible is that it will
not work due to interlocking etc.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

A good start can be found here.

http://igor.chudov.com/manuals/Bridg.../Chapter-4.pdf

there is a power distribution schematic. It does not look very
discouraging. But I would be leery of altering this mill.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
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Ignoramus26200 wrote:
On 2009-01-20, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.

Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

I _could_ re-design all the speed control circuitry and hardware so
that it controlled a VFD, but it's a closed-loop system as it now
exists, and it wouldn't be a simple re-work.

My goal right now is to get the machine full-up working _as_designed_,
THEN think about an upgrade or retro-fit of the electronics.

In addition to that, it will take some re-wiring anyway, because the
R2E3 and R2E4 main electronics supplies derive their power from two
phases of the 3-phase, rather than only one.

LLoyd
Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.



Pete, if I understood Lloyd right, and I think that I heard the same
thing a while ago from someone else, the BOSS controls really need all
three phases to operate. And then from then on, all control circuitry
is 220v or 110v based and thus you need extra relays and stuff just to
operate the VFDs which usually use 10v for signaling.

The axis drives are single phase.

As for control voltages, the VFD will accept a dry contact closure for
run, and there is certainly a contactor controlling the spindle now that
will readily provide that dry contact closure with 5 min of rewiring.


Easy with a phase converter, hard with drives.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

It may not be so simple because contactors may be interlocked with one
another in a way that requires 110 or 220v. (something like, the
spindle must be running in order to move table, etc)

What you say is possible, but what is also possible is that it will
not work due to interlocking etc.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.



A good start can be found here.

http://igor.chudov.com/manuals/Bridg.../Chapter-4.pdf

there is a power distribution schematic. It does not look very
discouraging. But I would be leery of altering this mill.


I didn't see a schematic, all I saw was a mediocre block diagram.

Give me a VFD of an appropriate size for the spindle motor, and a couple
hours and I'd have the machine happily running on a 240V 1ph input.

Ignoramus26200 wrote:
On 2009-01-20, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.

Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

I _could_ re-design all the speed control circuitry and hardware so
that it controlled a VFD, but it's a closed-loop system as it now
exists, and it wouldn't be a simple re-work.

My goal right now is to get the machine full-up working _as_designed_,
THEN think about an upgrade or retro-fit of the electronics.

In addition to that, it will take some re-wiring anyway, because the
R2E3 and R2E4 main electronics supplies derive their power from two
phases of the 3-phase, rather than only one.

LLoyd
Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

Pete, if I understood Lloyd right, and I think that I heard the same
thing a while ago from someone else, the BOSS controls really need all
three phases to operate. And then from then on, all control circuitry
is 220v or 110v based and thus you need extra relays and stuff just to
operate the VFDs which usually use 10v for signaling.

Easy with a phase converter, hard with drives.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

It may not be so simple because contactors may be interlocked with one
another in a way that requires 110 or 220v. (something like, the
spindle must be running in order to move table, etc)

What you say is possible, but what is also possible is that it will
not work due to interlocking etc.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

A good start can be found here.

http://igor.chudov.com/manuals/Bridg.../Chapter-4.pdf

there is a power distribution schematic. It does not look very
discouraging. But I would be leery of altering this mill.


Per your chapter 4, the two transformers are single phase, so they can
each be wired to the 240V single phase supply and their taps set
appropriatly.

The three phas goes only to the spindle motor start/reversing contactor.
contacts from the start/reversing contactor can be used for the
VFD control, or better yet, those contactors are most likely driven by
smaller relays in the control and the contacts of those relays would be
a better choice to use.

Either way, a $200 VFD and a couple hours work. Very simple.

Where was Lloyd located anyway? I've got some comp time to blow...

Pete C.

"Pete C." fired this volley in news:gl5kip$b33$1
@news.motzarella.org:

The "two phases" feeding the controls simply connect to your 240V
single
phase feed with appropriate voltage tap adjustments.

Nope. One AC supply runs off one 240V phase, a DC supply runs off a
second 240V phase, and the motor runs off all three.

The motor controls are nearly as simple. You locate the contactor
....snip
Nothing else in the maching needs
three phase power,

True, but I still have to rewire the main harness to get both internal
supplies on one phase.

No noisy and inneficient RPC, just a small, silent VFD to stick on
or in
the control cabinet.

Unfortunately, it's also about four to eight times the cost for that
VFD than what my RPC (locate OUTSIDE the shop, and thus "silent")
would cost.

Oddly... even the folks who sell retro-fit kits for the R2E4,
converting them entirely to new electronics, don't seem to want to
mess with the spindle motor. They sell VFDs. They recommend an RPC
for that machine. (?)


LLoyd

"Pete C." fired this volley in news:gl5p0g$rp0$1
@news.motzarella.org:

Either way, a $200 VFD and a couple hours work. Very simple.


Ok... but my 3HP RPC cost me $63, all up, including a brand new motor.

And you still told us "rewiring". Well... If I have to re-wire the
cabinet anyway, why not get the machine working per stock, first.
THEN mess with it, if it seems reasonable. I don't have any
particular love for the old technology, but it's a good foundation to
thoroughly understand how the hardware, electronics, and firmware
interact.

BTW... I'm in Northeast Central Florida. (it's even cold here for the
next two days). If you've got a spare 2HP VFD and the time, "come on
DOWN!" G.


LLoyd

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5kip$b33$1
@news.motzarella.org:
The "two phases" feeding the controls simply connect to your 240V
single
phase feed with appropriate voltage tap adjustments.



Nope. One AC supply runs off one 240V phase, a DC supply runs off a
second 240V phase, and the motor runs off all three.
The motor controls are nearly as simple. You locate the contactor

Yep, they are two seperate single phase transformers, they each connect
to your 240V input. They were only connected to seperate phases on the
three phase supply to better balance the load on the three phase and
lower the amperage requirements.

...snip
Nothing else in the maching needs
three phase power,

True, but I still have to rewire the main harness to get both internal
supplies on one phase.

That's just a few wires, 30 min of work.


No noisy and inneficient RPC, just a small, silent VFD to stick on
or in
the control cabinet.

Unfortunately, it's also about four to eight times the cost for that
VFD than what my RPC (locate OUTSIDE the shop, and thus "silent")
would cost.

The used VFDs I got from Iggy for $100ea would do it. New ones for a 2hp
spindle are a couple hundred dollars.


Oddly... even the folks who sell retro-fit kits for the R2E4,
converting them entirely to new electronics, don't seem to want to
mess with the spindle motor. They sell VFDs. They recommend an RPC
for that machine. (?)

Don't know, haven't seen their retrofit packages.

From Iggy's docs, there is nothing special about the spindle motor. The
speed control setup is funky and probably not worth messing with, but
that in no way precludes the use of a VFD set for simple 60hz output to
power the spindle motor.

I spent some 5+ years doing CNC service BTW, however, the machines I
worked on were generally newer. How far are you from Dallas anyway?

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5p0g$rp0$1
@news.motzarella.org:

Either way, a $200 VFD and a couple hours work. Very simple.


Ok... but my 3HP RPC cost me $63, all up, including a brand new motor.

And you still told us "rewiring". Well... If I have to re-wire the
cabinet anyway, why not get the machine working per stock, first.

The "rewiring" is barely more than the power connections. The power
inputs to the two transformers and the VFD, the connection from the VFD
to the spindle motor, and the three wires for the control connection to
the VFD.

THEN mess with it, if it seems reasonable. I don't have any
particular love for the old technology, but it's a good foundation to
thoroughly understand how the hardware, electronics, and firmware
interact.

Yes, but I consider "mess with it" as retrofit for Mach3, not just
rewire power and a VFD to get it running on single phase.


BTW... I'm in Northeast Central Florida. (it's even cold here for the
next two days). If you've got a spare 2HP VFD and the time, "come on
DOWN!" G.

Actually, I do have a spare 3HP VFD on hand (got two from Iggy, one is
on my Bridgeport now), and some comp time available. Got any good dive
sites in the area? On second though scratch the dive thing, it's cold
and I loaned my dry suit to someone in my dive club.

I could stick the spare VFD in the priority mail pretty easily...

"Pete C." fired this volley in news:gl5qj1$fs9$1
@news.motzarella.org:

I could stick the spare VFD in the priority mail pretty easily...

That, I really appreciate, Pete. Thanks. How much?

I might take you up on that, because my goal really IS to overhaul
this beautiful hunk'o'metal into a modern machine. But right now, I
have the RPC, it IS outside my machine room (out in the compressor
shack), and it works fine. So, all I have to do is move around a
couple of harness wires to get the two transformers on one phase, and
I should be (hope!) cutting metal.

The machine was presumably "in service" when they unplugged it to load
on my trailer.

However, as you maintained -- If I ran it off a VFD, it would at least
be quieter and more efficient. It will get one sooner or later.

One question, please. How's the "spin up time" on a VFD-powered motor
that's triggered externally like you recommend, vs. a motor running on
an extant 3-phase supply switched by a contactor? I don't know what
the BOSS controller expects, in terms of wait time for expected RPM.

LLoyd

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5qj1$fs9$1
@news.motzarella.org:

I could stick the spare VFD in the priority mail pretty easily...

That, I really appreciate, Pete. Thanks. How much?

I got it from Iggy for $100 and figured I'd keep a spare on hand or for
future projects. I could send it to you to try out if you want.


I might take you up on that, because my goal really IS to overhaul
this beautiful hunk'o'metal into a modern machine. But right now, I
have the RPC, it IS outside my machine room (out in the compressor
shack), and it works fine. So, all I have to do is move around a
couple of harness wires to get the two transformers on one phase, and
I should be (hope!) cutting metal.

If you already have the RPC up, you can certainly test the machine on
it. The VFD is ultimitely where you want to go however.

Upgrading to a "modern machine" is certainly an involved project, but
there are a lot of resources available these days.

I'm building up a small CNC plasma table based on Mach3 at the moment. I
expect to have it completed in a month or two.


The machine was presumably "in service" when they unplugged it to load
on my trailer.

However, as you maintained -- If I ran it off a VFD, it would at least
be quieter and more efficient. It will get one sooner or later.

Yep. I believe Driveswarehouse.com is a decent source.


One question, please. How's the "spin up time" on a VFD-powered motor
that's triggered externally like you recommend, vs. a motor running on
an extant 3-phase supply switched by a contactor? I don't know what
the BOSS controller expects, in terms of wait time for expected RPM.


Spin up, spin down, dynamic braking, speeds, etc. are all programmable
on a VFD. For your application you'd be looking at setting the VFD for
60hz output, and zero acceleration ramp (immediate full speed), and
probably coast on stop to match the original performance since there is
a brake in the machine.

"Pete C." fired this volley in news:gl5s3e$tka$1
@news.motzarella.org:

Pete, if you can sit on that "test deal" for a few weeks, I'll probably
take you up on it, and either return it or pay for it, as you choose
after I'm done.

Right now, I'm busting out a 2-1/2" slab section, and re-forming for a
5" pour in and around where the new machine will sit. (one expenditure
begets another... sigh...)

LLoyd

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5s3e$tka$1
@news.motzarella.org:

Pete, if you can sit on that "test deal" for a few weeks, I'll probably
take you up on it, and either return it or pay for it, as you choose
after I'm done.

Right now, I'm busting out a 2-1/2" slab section, and re-forming for a
5" pour in and around where the new machine will sit. (one expenditure
begets another... sigh...)

LLoyd

No problem, just delete the .DOH. to eamil me.

On 2009-01-21, Pete C. wrote:

Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5qj1$fs9$1
@news.motzarella.org:

I could stick the spare VFD in the priority mail pretty easily...

That, I really appreciate, Pete. Thanks. How much?

I got it from Iggy for $100 and figured I'd keep a spare on hand or for
future projects. I could send it to you to try out if you want.

How is the other one, working for you? Sounds like you are happy.

By the way I have more, some I can sell for cheap due to cosmetic
damage.


I might take you up on that, because my goal really IS to overhaul
this beautiful hunk'o'metal into a modern machine. But right now, I
have the RPC, it IS outside my machine room (out in the compressor
shack), and it works fine. So, all I have to do is move around a
couple of harness wires to get the two transformers on one phase, and
I should be (hope!) cutting metal.

If you already have the RPC up, you can certainly test the machine on
it. The VFD is ultimitely where you want to go however.

Upgrading to a "modern machine" is certainly an involved project, but
there are a lot of resources available these days.

I am very happy with a VFD on my mill.

I wish I could put one on my lathe, but this 40 year old motor that is
220v only, has bad insulation and leaks through insulation if powered
by a VFD.

I'm building up a small CNC plasma table based on Mach3 at the moment. I
expect to have it completed in a month or two.


The machine was presumably "in service" when they unplugged it to load
on my trailer.

However, as you maintained -- If I ran it off a VFD, it would at least
be quieter and more efficient. It will get one sooner or later.

Yep. I believe Driveswarehouse.com is a decent source.


One question, please. How's the "spin up time" on a VFD-powered motor
that's triggered externally like you recommend, vs. a motor running on
an extant 3-phase supply switched by a contactor? I don't know what
the BOSS controller expects, in terms of wait time for expected RPM.


Spin up, spin down, dynamic braking, speeds, etc. are all programmable
on a VFD. For your application you'd be looking at setting the VFD for
60hz output, and zero acceleration ramp (immediate full speed), and
probably coast on stop to match the original performance since there is
a brake in the machine.

With a braking resistor, I programmed my mill to stop in 0.5 seconds
with electric braking.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

Ignoramus26200 wrote:
On 2009-01-21, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:gl5qj1$fs9$1
@news.motzarella.org:

I could stick the spare VFD in the priority mail pretty easily...
That, I really appreciate, Pete. Thanks. How much?
I got it from Iggy for $100 and figured I'd keep a spare on hand or for
future projects. I could send it to you to try out if you want.

How is the other one, working for you? Sounds like you are happy.

It's working very nicely. Having it mounted on the wall next to the
Bridgeport works just fine. The only times I change speed I'm also
changing tooling so reaching over and entering a new fewquency works
fine. Otherwise with the original Brideport switch feeding the fwd/rev
inputs it's just as easy as normal.


By the way I have more, some I can sell for cheap due to cosmetic
damage.

You should post what's available. Lloyd will be wanting one, probably
other folks. Not sure if I need another at the moment since I don't have
any more three phase machines.


I might take you up on that, because my goal really IS to overhaul
this beautiful hunk'o'metal into a modern machine. But right now, I
have the RPC, it IS outside my machine room (out in the compressor
shack), and it works fine. So, all I have to do is move around a
couple of harness wires to get the two transformers on one phase, and
I should be (hope!) cutting metal.
If you already have the RPC up, you can certainly test the machine on
it. The VFD is ultimitely where you want to go however.

Upgrading to a "modern machine" is certainly an involved project, but
there are a lot of resources available these days.

I am very happy with a VFD on my mill.

In a lot of ways they're better than having real three phase power.


I wish I could put one on my lathe, but this 40 year old motor that is
220v only, has bad insulation and leaks through insulation if powered
by a VFD.

I bet a motor shop could re-varnish and bake that motor and get it in
better shape. Adding a line reactor between it and the VFD might help.
Or of course you could scroung a better motor.


I'm building up a small CNC plasma table based on Mach3 at the moment. I
expect to have it completed in a month or two.

The machine was presumably "in service" when they unplugged it to load
on my trailer.

However, as you maintained -- If I ran it off a VFD, it would at least
be quieter and more efficient. It will get one sooner or later.
Yep. I believe Driveswarehouse.com is a decent source.

One question, please. How's the "spin up time" on a VFD-powered motor
that's triggered externally like you recommend, vs. a motor running on
an extant 3-phase supply switched by a contactor? I don't know what
the BOSS controller expects, in terms of wait time for expected RPM.

Spin up, spin down, dynamic braking, speeds, etc. are all programmable
on a VFD. For your application you'd be looking at setting the VFD for
60hz output, and zero acceleration ramp (immediate full speed), and
probably coast on stop to match the original performance since there is
a brake in the machine.

With a braking resistor, I programmed my mill to stop in 0.5 seconds
with electric braking.


I just set mine to 1 sec start and 1 sec stop. 1 sec is certainly faster
than the stock coast to a stop.

On 2009-01-20, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.


Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

[ ... ]

Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

Assuming that it is not like the Bridgeport Series 1 BOSS-3
through BOSS-6. Those have a *big* three phase transformer in the back
power box, with each phase separately feeding a saturable reactor and a
bridge rectifier and filter capacitors. These three supplies power the
three large stepper motors. The power needed by these steppers is
sufficient tha they felt that they needed to spread it out over the
three phases. The actual computer and lower power driver circuits are
all derived from a single phase as you describe below.

Later versions, starting with the BOSS-8 used servo motors, and
were not nearly as power hungry, so they could be driven from single
phase except for the spindle motor.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

Unless it is an old stepper motor driven axis machine, in which
case it may indeed be using the full three phases to power those
electronics.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

An imbalanced (voltage mode) RPC can fry the power transistors
driving the stepper motors on this old design, so if you use a RPC, you
need to take care to balance it beforehand -- at least with the
BOSS-[3-6]).

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Ignoramus26200 fired this volley
in :

I wish I could put one on my lathe, but this 40 year old motor that
is
220v only, has bad insulation and leaks through insulation if
powered
by a VFD.


Not sinusoidal or modified sine-wave output from the VFD? What leaks,
where?

40 years ago, they were using sophisticated varnishes on magnet wire.
That's way later than the leaky old cotton or silk days. Of that, I
know. I worked in the research and testing lab for Florida Transitron
in 1968-69, before 'Nam slapped me out of the work-force for a couple
of years.

(and to paraphrase someone you might know personally... Used 3-phase
motors are a dime-a-dozen G)

LLoyd

DoN. Nichols wrote:
On 2009-01-20, Pete C. wrote:
Lloyd E. Sponenburgh wrote:
"Pete C." fired this volley in news:497509cc$0
:

Sure he can. If he were reasonable close to Dallas I'd offer to
help. A
lot of stuff takes three phase power but doesn't actually use it as
three phase.

Unless I want to re-design the mill AND the controls, Iggy's right.

The motor on an R2E4 is constant-speed. Speed is controlled by
valving air cylinders and brakes to control a variable-pitch sheave.

[ ... ]

Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

Assuming that it is not like the Bridgeport Series 1 BOSS-3
through BOSS-6. Those have a *big* three phase transformer in the back
power box, with each phase separately feeding a saturable reactor and a
bridge rectifier and filter capacitors. These three supplies power the
three large stepper motors. The power needed by these steppers is
sufficient tha they felt that they needed to spread it out over the
three phases. The actual computer and lower power driver circuits are
all derived from a single phase as you describe below.

Later versions, starting with the BOSS-8 used servo motors, and
were not nearly as power hungry, so they could be driven from single
phase except for the spindle motor.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

Unless it is an old stepper motor driven axis machine, in which
case it may indeed be using the full three phases to power those
electronics.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

An imbalanced (voltage mode) RPC can fry the power transistors
driving the stepper motors on this old design, so if you use a RPC, you
need to take care to balance it beforehand -- at least with the
BOSS-[3-6]).

Enjoy,
DoN.


Iggy's docs indicate it is a servo driven system and that the power
supplies are all single phase.

"DoN. Nichols" fired this volley in
:

An imbalanced (voltage mode) RPC can fry the power transistors
driving the stepper motors on this old design, so if you use a RPC,
you
need to take care to balance it beforehand -- at least with the
BOSS-[3-6]).


BOSS-9, Don. Pete was right in all respects, except that the two
internal supplies do run off two phases. But they certainly can be
made to run off one. The BOSS-9 R2E4 is all servo driven, and not
power-hungry, at all.

LLoyd

On 2009-01-20, Ignoramus26200 wrote:
On 2009-01-20, Pete C. wrote:

[ ... ]

Sorry for the delay in getting back to you, I've been having some news
server / client issues.

You are thinking too complicated, it is really very, very simple.

The "two phases" feeding the controls simply connect to your 240V single
phase feed with appropriate voltage tap adjustments.

Pete, if I understood Lloyd right, and I think that I heard the same
thing a while ago from someone else, the BOSS controls really need all
three phases to operate.

Probably from me -- and this only applies that I am sure of for
the BOSS-3 through BOSS-6 machines. BOSS-8 had moved to servo motors
instead of steppers, and are probably easier to run from single phase
(except for the spindle motor, of course.)

Looking at the manual chapter which you posted a link to, this
appears to be for the later ones, with a single power supply providing
128 VDC for all three axes from a single power supply -- thus it is
probably running servo motors and servo amps (the "Motor Drive Module
Assemblies"). This one will be easier to convert than the BOSS-[3-6]
machines are.

The BOSS-[3-6] machines have a *big* three-phase transformer,
providing lower voltage AC to each axis motor electronics from a
different phase.

Each phase goes through a saturable reactor (mag-amp) and a
bridge rectifier to a filter capacitor to provide power to the stepper
driver for that axis. When stopped and stepping slowly, there is no
current through the control winding of the mag-amp, so the voltage
reaching the rectifier and filter capacitor is reduced to about 50V DC
or less out of the filter. However, when stepping rapidly, a DC current
is fed through the control winding, lowering the inductance greatly, and
getting more of the AC through the bridge rectifier through to the
filter capacitor (and the stepper drivers and motor). This produces an
80V power to the stepper motors to overcome the inductance of the
stepper windings.

The stepper motor machines have big cooling fins on each stepper
motor to deal with the heat from the current. The servo motors are just
plain cylinders with brush caps sticking out.

And then from then on, all control circuitry
is 220v or 110v based and thus you need extra relays and stuff just to
operate the VFDs which usually use 10v for signaling.

Easy with a phase converter, hard with drives.

The motor controls are nearly as simple. You locate the contactor
currently controlling the three phase spindle motor, and disconnect the
motor and power connection from it. Select one set of contacts on this
contactor and they will connect to the run/stop input on the VFD (and
it's control common). The VFD input power connects to your 240V single
phase supply. The VFD output connects to the spindle motor.

When the control starts the spindle by closing the contactor, the VFD
receives it's control input and starts the spindle motor. When the
control stops the spindle, the VFD receives the control input and stops
the spindle motor.

It may not be so simple because contactors may be interlocked with one
another in a way that requires 110 or 220v. (something like, the
spindle must be running in order to move table, etc)

At least on mine, the contactors are mechanically interlocked.
Actuate one (with a short pulse of AC) and the other drops out before
the first closes.

IIRC, the contactor coils run from 120 VAC (developed from a
large step-down transformer which powers other things as well), and they
are controlled by a 24 VCD coil relay plugged into an octal socket in
the computer rack on the opposite side of the machine itself. (There
are three boxes -- high power on the back, electronics on the right (as
seen from the operator's position, and the interlocked reversing relay
in another box on the side which also contains an outlet for a coolant
pump, and another outlet for an operator's light.

If you are running the spindle motor from a VFD, you want to get
rid of the interlock reversing relay, and give low-voltage commands to
the VFD (easily derived from the relay which switches the reversing
contactor.

I really should scan all of what I have for the older machines
and send to you -- but too many of the pages are too large for me to
scan reasonably, and I'm having problems getting the just acquired SGI
computer (which comes with scanning software) to talk to the SCSI
interfaced HP Color Scanjet 5c. (It is expecting a Scanjet IIc at best,
I think.) The manual has gazillions of fold-out schematics too big for
my scanner.

What you say is possible, but what is also possible is that it will
not work due to interlocking etc.

No reversing contactors should be between the VFD and the spindle
motor. The VFD should receive commands to stop or to run forward or
reverse -- at the 5V or 10V level.

No changes to the speed controls are required. The speed continues to be
controlled normally.

The only thing you rewire is the only thing in the machine that needs
three phase power - the spindle motor. Nothing else in the maching needs
three phase power, and the control only cares that the motor starts when
it closes it's control contactor.

No noisy and inneficient RPC, just a small, silent VFD to stick on or in
the control cabinet.

A good start can be found here.

http://igor.chudov.com/manuals/Bridg.../Chapter-4.pdf

there is a power distribution schematic. It does not look very
discouraging. But I would be leery of altering this mill.

It all depends on which version of the BOSS series he has. If
it is BOSS-3 through BOSS-6, then things are more difficult. If it is a
BOSS-8 or later, things are easier, and match your manuals. And your
chapter 4 is a *lot* shorter than mine. :-)

Enjoy,
DoN.

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On 2009-01-21, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ignoramus26200 fired this volley
in :

I wish I could put one on my lathe, but this 40 year old motor that
is
220v only, has bad insulation and leaks through insulation if
powered
by a VFD.


Not sinusoidal or modified sine-wave output from the VFD? What leaks,
where?

40 years ago, they were using sophisticated varnishes on magnet wire.
That's way later than the leaky old cotton or silk days. Of that, I
know. I worked in the research and testing lab for Florida Transitron
in 1968-69, before 'Nam slapped me out of the work-force for a couple
of years.

(and to paraphrase someone you might know personally... Used 3-phase
motors are a dime-a-dozen G)

Lloyd, used three phease motors are a dome a dozen. I brought home two
yesterday, one cost me $10 and another $15, both 2 HP.

What is not as easy to find is a 2 speed motor.

My alternative is to put a 5 HP inverter duty motor (which I have,
also 184T) in the lathe, and rewire the starting lever to operate the
drive instead. I am not in a hurry to do it, since the lathe works as
of now. I postponed it until I would understand it condition a little
better.


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On 2009-01-21, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:

[ ... ]

40 years ago, they were using sophisticated varnishes on magnet wire.
That's way later than the leaky old cotton or silk days. Of that, I
know. I worked in the research and testing lab for Florida Transitron
in 1968-69, before 'Nam slapped me out of the work-force for a couple
of years.

Hmm ... I worked for the original Wakefield Transitron, and one
in East Boston.

What ever happened to them over the years?

Enjoy,
DoN.

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