How to setup a 3-phase 240V to 480V transformer?
 

I just bought my first lathe, which is a Rivett 1020S, and I'm
obviously excited and ready to get it running. The motor is a 3-phase
5HP 240/480V and it is currently wired for 480V.

I plan to setup a phase converter using at least a 3-phase 240V 10HP
motor.

I've never setup a transformer to increase the voltage from my
converted 3-phase 240V to 480V and so I'm seeking advice on this.

Instead of the 10HP 3-phase 240V motor for the phase converter, will I
need to increase the HP any? Does this motor need to be a 240/480V?

Thanks in advance for any advice.

How to setup a 3-phase 240V to 480V transformer?
 

It should be a six lead motor.
There is probably a diagram on the nameplate showning the lead
numbers which will be marked in the motor junction box.
in general the wiring scheme is:

480V. 240V.
Com. Ph.A Ph.A Ph.A
.| |. .| |.
/ \ / \
coil coil coil coil
Ph. C _./ \._ Com. Ph. C_./ \._ Ph. B

Com.-.___coil___._ Ph.B Ph. C -.____coil___._ Ph. B

Com.= leads tied together.

Be careful to get the rotation right.

Sorry but this dinky little diagram is the best I can do.
MadDog

How to setup a 3-phase 240V to 480V transformer?
 

On 17 Apr 2006 15:45:17 -0700, "Mark Main" wrote:

When I open the power panel on the end of the lathe I see the 3 wires
for the service power... but those wires hook into what looks like a
fairly complex power panel (I think it's the original Vari-Drive), and
from that it leads to the motor. I've never rewired a motor from 480V
to 240V.

I would prefer doing this the simplest way possible and so wiring 240V
would be great if I knew how to do it. Thanks.
Greetings Mark,
We need the motor data to help you. Someone here should be able to
tell you how to connect the motor for 240 volt operation. If the motor
is dual voltage then it makes sense that the control electrics will
also work with either 240 or 480 volts. Anyway, if you have 240 volt
service, then it will be lots easier and cheaper to build a 240 volt
rotary phase converter and change the internal motor connections. It's
not like you need to remove the motor windings and have it re-wound.
The motor will probably have 9 wires that can be connected two
different ways for either 240 or 480 volt operation. A common wiring
configuration is having the wires numbered 1 through 9. For 480 volt
operation the wires would be connected thusly: 6+9, 5+8, 4+7, with
wires 3, 2, and 1 connected to the power. For 240 volts the
connections a 6+5+4, 9+3, 8+2, 7+1, with the power again connected
to wires 3, 2, and 1. Of course, since this is a three phase motor,
swapping any two of the three power wires will reverse the motor. I
bet someone here has the actual wiring specs for your lathe.
ERS

How to setup a 3-phase 240V to 480V transformer?
 

Hey Mark,

So far, all the replies have been about "the motor", and simply
rewiring it. I am not at all familiar with what else might be on your
Rivett lathe, but I think, as you do, that it will be more than just
the main spindle motor.

That said, I still think that the best advice is to change the taps
and terminals to suit the 240, but it won't be as simple as has so far
been stated, and maybe you should get some assistance from somebody
close by that can help, or at least be asking for a complete set of
wiring schematics for the model you have. It is quite possible that
in fact the "whole machine" can be switched form 440 to 220, and has
an internal transformer to do so, and that with a schematic you'll see
what wires have to go where.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX.




On Mon, 17 Apr 2006 17:20:52 -0700, Eric R Snow
wrote:

On 17 Apr 2006 15:45:17 -0700, "Mark Main" wrote:

When I open the power panel on the end of the lathe I see the 3 wires
for the service power... but those wires hook into what looks like a
fairly complex power panel (I think it's the original Vari-Drive), and
from that it leads to the motor. I've never rewired a motor from 480V
to 240V.

I would prefer doing this the simplest way possible and so wiring 240V
would be great if I knew how to do it. Thanks.
Greetings Mark,
We need the motor data to help you. Someone here should be able to
tell you how to connect the motor for 240 volt operation. If the motor
is dual voltage then it makes sense that the control electrics will
also work with either 240 or 480 volts. Anyway, if you have 240 volt
service, then it will be lots easier and cheaper to build a 240 volt
rotary phase converter and change the internal motor connections. It's
not like you need to remove the motor windings and have it re-wound.
The motor will probably have 9 wires that can be connected two
different ways for either 240 or 480 volt operation. A common wiring
configuration is having the wires numbered 1 through 9. For 480 volt
operation the wires would be connected thusly: 6+9, 5+8, 4+7, with
wires 3, 2, and 1 connected to the power. For 240 volts the
connections a 6+5+4, 9+3, 8+2, 7+1, with the power again connected
to wires 3, 2, and 1. Of course, since this is a three phase motor,
swapping any two of the three power wires will reverse the motor. I
bet someone here has the actual wiring specs for your lathe.
ERS

How to setup a 3-phase 240V to 480V transformer?
 

That model has an electrically driven speed control and an oil pump
(which may or may not have its own motor). Those may have to be
rewired as well -- but they probably don't operate on 480 volts now
and may already be wired for 220.

Ignoramus22652 wrote:

Mark, you made me confused, why don't you rewire the 240/480 lathe
motor to run off 240V? That would be easiest and would not require
buying a bulky, and costly transformer, as well as eliminate
transformer losses.

i

How to setup a 3-phase 240V to 480V transformer?
 

Mark,
This is entirely doable. I have a RPC giving me my 240 3 ph. It is
wired into a 240V distribution panel and a transformer. The
transformer takes 240 3ph in and 480 3ph out. Then I go into a 480
distribution panel. The cost of the used transformer, panel and wiring
was about $300.

I had one piece of equipment that was impracical to convert to 240 from
480. The coils for the starter would have had to be changed,
everything else switched, so I wanted to run it on 480. 2 other lathes
were 480 only. I can run smaller wire and the large motors start
easier on high voltage.

This was especially proven to me on my air compressor. On 240 I could
not start it when cold. On 480, the compressor starts much easier and
faster.

Now I have the option to run most equipment and not have to worry about
converting.

Bob

How to setup a 3-phase 240V to 480V transformer?
 

Thanks to all for writing in and helping. I've been working tons of
overtime hours and so I had to wait for the weekend to look at the
motor.

I looked at the wire diagram on the motor and it's exactly as Eric
stated. I only see lables for wires 1, 2 & 3 from my motor and so I'm
going to try and figure out which wire number belong to the others.

The motor has the following listed on another plate:

Star Kimble
5 HP Constant Duty
60 Hz
13.4/6.7A
220/440V
1690 RPM
254 Type/Frame

Let me know if you need any other information. I've taken some
pictures but I misplaced my cord to load them into my computer. I'll
find it and load them for you to see close-ups of stuff.

Thanks again to all for your help.

How to setup a 3-phase 240V to 480V transformer?
 

According to Mark Main :

[ ... ]

Let me know if you need any other information. I've taken some
pictures but I misplaced my cord to load them into my computer. I'll
find it and load them for you to see close-ups of stuff.

Hmm ... what media in the camera? CF, SD, one of the others?
There are quite inexpensive USB devices in your local computer store
(I've found mine in Micro Center, FWIW) which will allow you read the
cards directly into the computer without the camera being involved. It
is much faster than doing so from the camera, and it is less strain on
the camera's battery as well.

You do know to post the images to the dropbox, not to the
newsgroup, I hope? The instructions can be found on the dropbox.

http://www.metalworking.com

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 ---