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