I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

KD wrote:
I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

Ask your electrical supply store for a "manual double throw three phase
transfer switch" with sufficient ampacity for the heavier of the two
loads. Wire it in where you can easily reach it to throw the handle.

Lots of companies make them.

If cost is a factor and you've got a well stocked electrical junk pile,
but no transfer switches in it...... You could use a couple of three
phase disconnect switches (fused or unfused) and rig some kind of a
mechanical interlock between them so that they won't both be "on" at the
same time. It shouldn't take much more than appropriate mounting
locations and some sort of center pivoted lever to accomplish that. (No
warranty from me on an electrical or insurance inspector "buying" it
though. G)

Good Luck,

Jeff

--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."

On Tue, 22 Jun 2004 12:35:19 -0400, the renowned Jeff Wisnia
wrote:

KD wrote:
I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

Ask your electrical supply store for a "manual double throw three phase
transfer switch" with sufficient ampacity for the heavier of the two
loads. Wire it in where you can easily reach it to throw the handle.

Lots of companies make them.

If cost is a factor and you've got a well stocked electrical junk pile,
but no transfer switches in it...... You could use a couple of three
phase disconnect switches (fused or unfused) and rig some kind of a
mechanical interlock between them so that they won't both be "on" at the
same time. It shouldn't take much more than appropriate mounting
locations and some sort of center pivoted lever to accomplish that. (No
warranty from me on an electrical or insurance inspector "buying" it
though. G)

Good Luck,

Jeff

I'd probably wire the two up and just remember not to switch both on
at once... but that would be wrong.

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

In article ,
what says...
On Tue, 22 Jun 2004 12:35:19 -0400, the renowned Jeff Wisnia
wrote:

KD wrote:
I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

Ask your electrical supply store for a "manual double throw three phase
transfer switch" with sufficient ampacity for the heavier of the two
loads. Wire it in where you can easily reach it to throw the handle.

Lots of companies make them.

If cost is a factor and you've got a well stocked electrical junk pile,
but no transfer switches in it...... You could use a couple of three
phase disconnect switches (fused or unfused) and rig some kind of a
mechanical interlock between them so that they won't both be "on" at the
same time. It shouldn't take much more than appropriate mounting
locations and some sort of center pivoted lever to accomplish that. (No
warranty from me on an electrical or insurance inspector "buying" it
though. G)

Good Luck,

Jeff

I'd probably wire the two up and just remember not to switch both on
at once... but that would be wrong.


That's what I do with my 3 phase machines that do not have
VFDs. As long as the wiring is adequate, in most case
there's no problem starting another machine when another is
already running, with either a static or rotary converter.
In other words, I don't understand why the OP feels it's
necessary to have only one machine connected at a time.

I do have a pair of 30A motor starting switches wired as
Jeff describes above to select either the rotary or static
converter. One switch is mounted upside down and a bar
between the handles prevents both from being on at the same
time.

Ned Simmons

Ned Simmons wrote:

snipped

I do have a pair of 30A motor starting switches wired as
Jeff describes above to select either the rotary or static
converter. One switch is mounted upside down and a bar
between the handles prevents both from being on at the same
time.

Ned Simmons


Hey, thanks Ned! I thought I was going to get all sorts of jazz from
folks for that "interlock" suggestion.

My first thought was to recommend your "upside down" (and I presume
offset by one width.) trick, but I wasn't sure how much an upside down
disconnect switch would agitate an inspector. G

That reminds of what some critic called Laurel and Hardy...."Two minds
without a single thought.."

Jeff

--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."

In article ,
says...
Ned Simmons wrote:

snipped

I do have a pair of 30A motor starting switches wired as
Jeff describes above to select either the rotary or static
converter. One switch is mounted upside down and a bar
between the handles prevents both from being on at the same
time.

Ned Simmons


Hey, thanks Ned! I thought I was going to get all sorts of jazz from
folks for that "interlock" suggestion.

My first thought was to recommend your "upside down" (and I presume
offset by one width.) trick, but I wasn't sure how much an upside down
disconnect switch would agitate an inspector. G

Inspector? You need a code before you can have an
inspector. This is a town with no shortage of multi-million
dollar waterfront homes with no building code or electrical
code. The State of Maine does require towns to have a
plumbing code and shoreland zoning, but that's about it.

Here's a photo of the switches...
http://www.suscom-maine.net/~nsimmons/XferSw.JPG

If anyone wants to do something like this I have quite a
few of those switches, 3 pole 30A @ 600VAC, 7.5/15/20 HP @
240/480/600 VAC 3 phase.


That reminds of what some critic called Laurel and Hardy...."Two minds
without a single thought.."


Speak for yourself, I thought it was pretty clever g.

Ned Simmons

"Jeff Wisnia" wrote in message
...
Ned Simmons wrote:

snipped

I do have a pair of 30A motor starting switches wired as
Jeff describes above to select either the rotary or static
converter. One switch is mounted upside down and a bar
between the handles prevents both from being on at the same
time.

Ned Simmons


Hey, thanks Ned! I thought I was going to get all sorts of jazz from
folks for that "interlock" suggestion.

My first thought was to recommend your "upside down" (and I presume
offset by one width.) trick, but I wasn't sure how much an upside down
disconnect switch would agitate an inspector. G

My commercially made MTS transfer panel works that way. It is impossible
to have our generator connected to the panel and still be connected to the
service. It's a slick way, and perfectly acceptable by code. They use a
Square D panel and add the interlock. Real slick system.

Harold

Why not just use a 3 phase power plug for the switching?
Either that or a large switch will do.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works every time it is tried!

Do you mean a static phase converter, a rotary phase converter or a VFD?

If you don't have a VFD and your machines have their own power switches, you
can keep both machines hooked up to the converter, you don't need a switch.
If you have a VFD its best to use a switch.

Paul T.

"KD" wrote in message
om...
I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

Use two disconnects, side-by-side, one upside-down, with the handles
duct-taped together...untill you make a bracket from metal.

--

"KD" wrote in message
om...
I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks

Hey KD,

Not sure I follow EXACTLY what you mean, but what I have done is
gang-mount three sockets for clothes dryers (6 bucks Canadian each)
side by side on the wall, all inter-connected as three phase ( instead
of two hots and a neutral). The 220 circuit breaker feeds two of
these legs. Then for my purposes, I've scrounged up five used plugs
from old clothes dryers (new = 15 bucks each.......at garage sale, a
buck or two). I've hooked each individual motor's leads for the
machines to the individual dryer plugs, including the rotary phase
convertor. For two of them, the cord set itself is long enough, and
for the other three I just joined the motor cab-tire to the cord set
with wire-nuts and taped them all up. Bit lumpy, but not bad if
you're neat. So I just plug in as required. Very simple, and I can
have just 220 single phase for a welder or whatever, by not wiring the
neutral on the plug.

Sorry if I've mis-understood, and this isn't what you meant.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXX
On 22 Jun 2004 08:51:47 -0700, (KD) wrote:

I have 2 machine tools both 3 phase. I have a phase converter. I have
been in the past, just pulling the 3 wires from the motor off of the
converter, and plugging in the motor wires from the other machine.
Its a bigger pain that it sounds. I am looking for some kind of swith
to just switch between the two without having to pull wires. ANybody
know what I should be looking for? Thanks for the help. if trying to
email me direct, email
Thanks