I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i

On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer.
Blows a fuse in the metering panel almost every time. So, the
transformer is never shut off using the circuit breakers.

Paul

On 2011-11-01, Paul Drahn wrote:
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer.
Blows a fuse in the metering panel almost every time. So, the
transformer is never shut off using the circuit breakers.

Paul, can you clarify this, how else do you shut it off?

And how do you switch it on? I am confused.

i

On Mon, 31 Oct 2011 22:27:54 -0500, Ignoramus23114
wrote:

I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
'Ayup. Works fine

Gunner, who does this several times a month


One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch

On 10/31/2011 9:23 PM, Ignoramus23114 wrote:
On 2011-11-01, Paul wrote:
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer.
Blows a fuse in the metering panel almost every time. So, the
transformer is never shut off using the circuit breakers.

Paul, can you clarify this, how else do you shut it off?

And how do you switch it on? I am confused.

i
We don't. The oven is turned on/off by an internal computer. So, if
power is off, we can't turn it on before powering up the oven. I think
the previous owner ran a 120 volt extension cord into the oven just to
power the computer. We chose not to try that. So, power to the oven is
on 24/7/365.

The transformer and oven are on their own 200 amp 208/3 meter. Each leg
has a 200 amp fuse right after the meter. They blow at about 201 amp!

For your use, connect up the equipment and turn it on before powering up
the transformer. Or permanently connect some other load, like a heater,
to the 460/3 circuit. Then add your new equipment to the line.

460/3 is not something to be careless with!

Paul

Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

On Tue, 01 Nov 2011 13:05:07 -0500, Ignoramus18836
wrote:

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

No. Startup surge will eithe pop the fuses..or take out the windings of
your motor in the RPCoverter.

Gunner

One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch

Hey Iggy,

Simple math says "Yes"....50Hp X 750 watts = 37500 Watts X 1.15 (15%
derate) = 43125 Watts, so your 45000 Watt transformer should do. What
size is the disconnect for the 45KVA fused at??? Needs close to 200
amps.

Brian Lawson,
Bo6thwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX

On Tue, 01 Nov 2011 13:05:07 -0500, Ignoramus18836
wrote:

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

On 2011-11-01, Brian Lawson wrote:
Hey Iggy,

Simple math says "Yes"....50Hp X 750 watts = 37500 Watts X 1.15 (15%
derate) = 43125 Watts, so your 45000 Watt transformer should do. What
size is the disconnect for the 45KVA fused at??? Needs close to 200
amps.

There is no disconnect, only the transformer in the back of my truck.

KVA is not watts and I am not sure if it is enough to start the
compressor.

i

Brian Lawson,
Bo6thwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX

On Tue, 01 Nov 2011 13:05:07 -0500, Ignoramus18836
wrote:

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

On 2011-11-01, Gunner Asch wrote:
On Tue, 01 Nov 2011 13:05:07 -0500, Ignoramus18836
wrote:

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

No. Startup surge will eithe pop the fuses..or take out the windings of
your motor in the RPCoverter.

There is no RPC there.

i

On Tue, 01 Nov 2011 14:52:19 -0500, Ignoramus18836
wrote:

On 2011-11-01, Brian Lawson wrote:
Hey Iggy,

Simple math says "Yes"....50Hp X 750 watts = 37500 Watts X 1.15 (15%
derate) = 43125 Watts, so your 45000 Watt transformer should do. What
size is the disconnect for the 45KVA fused at??? Needs close to 200
amps.

There is no disconnect, only the transformer in the back of my truck.

KVA is not watts and I am not sure if it is enough to start the
compressor.

i

Brian Lawson,
Bo6thwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX

On Tue, 01 Nov 2011 13:05:07 -0500, Ignoramus18836
wrote:

On 2011-11-01, Cydrome Leader wrote:
Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.

you sure can, but may need to fiddle with the taps to get the voltages
right.

OK, thanks.

I have another question. I bought a 50 HP rotary screw compressor for
resale. I want to test it.

I realized today that it is 460v. Would this 45 kva transformer, be
able to run this compressor UNLOADED, just as a power up test -- not
pumping at full PSI.

Thanks

That would be a hell of a load to start on temp wiring. Now, put a
soft start on it and it would be a piece of cake.

Karl

"Paul Drahn" wrote in message
...
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer. Blows
a fuse in the metering panel almost every time. So, the transformer is
never shut off using the circuit breakers.


I switch power into an unloaded 30kva transformer via a 20 amp triplex
breaker every single day withouy any problems whatsoever.

On 11/1/2011 4:14 PM, PrecisionmachinisT wrote:
"Paul wrote in message
...
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer. Blows
a fuse in the metering panel almost every time. So, the transformer is
never shut off using the circuit breakers.


I switch power into an unloaded 30kva transformer via a 20 amp triplex
breaker every single day withouy any problems whatsoever.



Ours is a 75kva. A 100 amp circuit breaker is between it and the meter
base with quick blow 200 amp fuses. Replaced one or more fuses in a two
week period. That cost more than running continuously for several years.

Paul

On 2011-11-02, Paul Drahn wrote:
On 11/1/2011 4:14 PM, PrecisionmachinisT wrote:
"Paul wrote in message
...
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer. Blows
a fuse in the metering panel almost every time. So, the transformer is
never shut off using the circuit breakers.


I switch power into an unloaded 30kva transformer via a 20 amp triplex
breaker every single day withouy any problems whatsoever.



Ours is a 75kva. A 100 amp circuit breaker is between it and the meter
base with quick blow 200 amp fuses. Replaced one or more fuses in a two
week period. That cost more than running continuously for several years.

Paul

What fuses do you need, I can sell you some cheaply. Let me know asap,
I will visit my fuse contact tomorrow.

i

On 11/1/2011 7:25 PM, Ignoramus18836 wrote:
On 2011-11-02, Paul wrote:
On 11/1/2011 4:14 PM, PrecisionmachinisT wrote:
"Paul wrote in message
...
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer. Blows
a fuse in the metering panel almost every time. So, the transformer is
never shut off using the circuit breakers.


I switch power into an unloaded 30kva transformer via a 20 amp triplex
breaker every single day withouy any problems whatsoever.



Ours is a 75kva. A 100 amp circuit breaker is between it and the meter
base with quick blow 200 amp fuses. Replaced one or more fuses in a two
week period. That cost more than running continuously for several years.

Paul

What fuses do you need, I can sell you some cheaply. Let me know asap,
I will visit my fuse contact tomorrow.

i
No, don't bother. I can't find out without shutting off the power to the
oven and pulling the fuse. I believe they used silver elements rated for
200 amp continuous and will blow at 202 amps.

It's been at least 4 years since we had the problem.

Paul

On Tue, 01 Nov 2011 14:52:19 -0500, Ignoramus18836
wrote:

On 2011-11-01, Brian Lawson wrote:
Hey Iggy,

Simple math says "Yes"....50Hp X 750 watts = 37500 Watts X 1.15 (15%
derate) = 43125 Watts, so your 45000 Watt transformer should do. What
size is the disconnect for the 45KVA fused at??? Needs close to 200
Hey Iggy,

There is no disconnect, only the transformer in the back of my truck.

?????? What ???????? What does that mean, and what does any of this
have to do with your truck?????

KVA is not watts and I am not sure if it is enough to start the
compressor.

You are correct of course. A watt is not a volt-amp. But you only
asked if the 45Kva transformer hooked step-up versus the step-down
mode it was designed for would handle the load of the 50Hp compressor
start-up. So send me the power-factor for the whole set-up I'll do it
again, accurate to one watt.

Take care. Have fun.

Brian Lawson.

On 2011-11-03, Brian Lawson wrote:
On Tue, 01 Nov 2011 14:52:19 -0500, Ignoramus18836
wrote:

On 2011-11-01, Brian Lawson wrote:
Hey Iggy,

Simple math says "Yes"....50Hp X 750 watts = 37500 Watts X 1.15 (15%
derate) = 43125 Watts, so your 45000 Watt transformer should do. What
size is the disconnect for the 45KVA fused at??? Needs close to 200
Hey Iggy,

There is no disconnect, only the transformer in the back of my truck.

?????? What ???????? What does that mean, and what does any of this
have to do with your truck?????

KVA is not watts and I am not sure if it is enough to start the
compressor.

You are correct of course. A watt is not a volt-amp. But you only
asked if the 45Kva transformer hooked step-up versus the step-down
mode it was designed for would handle the load of the 50Hp compressor
start-up. So send me the power-factor for the whole set-up I'll do it
again, accurate to one watt.

Brian, I will see, first, if I can rewire the compressor to 230v... It
may be easier than messing around with power factors and unknowns.

i

"Paul Drahn" wrote in message
...
On 11/1/2011 4:14 PM, PrecisionmachinisT wrote:
"Paul wrote in message
...
On 10/31/2011 8:27 PM, Ignoramus23114 wrote:
I have bought a 3 phase 45 kvs transformer 480 - 240.

Since I buy and sell industrial equipment, I will be sure to come
across 460v only machines. So, I thought, I could use this transformer
to make 460v from 230v, which is what my building has.

So, realistically, can it be used in reverse? to make 460v.


i
Sure. We have been using such a configuration for 5-6 years to power a
large convection oven that melts the solder paste on circuit boards. The
KVA rating is reduced about 10-15%.

We learned the hard way to never switch on an unloaded transformer.
Blows
a fuse in the metering panel almost every time. So, the transformer is
never shut off using the circuit breakers.


I switch power into an unloaded 30kva transformer via a 20 amp triplex
breaker every single day withouy any problems whatsoever.



Ours is a 75kva. A 100 amp circuit breaker is between it and the meter
base with quick blow 200 amp fuses. Replaced one or more fuses in a two
week period. That cost more than running continuously for several years.


Just sayin...

--people all around the world routinely switch unloades transformers on and
off without any problem whatsoever--and so it's definitely something else
that's wrong with whatever situation you have going on causing the problem
there.

Paul Drahn wrote:


We learned the hard way to never switch on an unloaded transformer.
Blows a fuse in the metering panel almost every time. So, the
transformer is never shut off using the circuit breakers.

Paul

I may be your experience, but it is one of those
"things that you know...That just ain't so"

The inrush to a transformer depends on several things, one of them is
the load, but the load ALWAYS adds to the inrush.

THe other things are the magnetic state the transformer core was left
at, and the where on the sine wave the voltage is at the moment you
close in.
jk

Paul Drahn wrote:



The transformer and oven are on their own 200 amp 208/3 meter. Each leg
has a 200 amp fuse right after the meter. They blow at about 201 amp!



The typical fuse curves for a 200A fuse would probably never reach
"minimum melt" at 201 A, at nominal temp, and would take several
hundred to several thousands of seconds at 300A.
For example an RK1 fuse
http://www.cooperindustries.com/cont...RK_70-600A.pdf
A 200A will melt in ~ 1000 seconds at 300A, 10 sec at ~1200A, and 1
sec at ~2200A.



jk

On 2011-11-03, jk wrote:
Paul Drahn wrote:



The transformer and oven are on their own 200 amp 208/3 meter. Each leg
has a 200 amp fuse right after the meter. They blow at about 201 amp!



The typical fuse curves for a 200A fuse would probably never reach
"minimum melt" at 201 A, at nominal temp, and would take several
hundred to several thousands of seconds at 300A.
For example an RK1 fuse
http://www.cooperindustries.com/cont...RK_70-600A.pdf
A 200A will melt in ~ 1000 seconds at 300A, 10 sec at ~1200A, and 1
sec at ~2200A.

He indicated that he has a very special fuse.

i

Ignoramus8802 wrote:



He indicated that he has a very special fuse.

i
Even semicon fuses don't blow that fast that low.

jk