Hi,
my father recently purchased a used piece of equipment. After plugging
it in one of the relays stuck. A repairman said it was because he had
the wrong form of 3 phase power. I'm a new to this but from the best I
can understand, I think he has 3 phase delta and the machine requires
wye.
Is there an easy way to test this, and what is the easiest fix?
Someone told him the power can be converted by using three transformers
but I havne't been able to find any information on how this is done, or
if it's even possible.
Any help would be greatly appreciated.
Thank you,
Dan
Please provide the information from the equipment name plate and I do
mean all of it. Is the equipment is 240 volt, 3 phase or is it 208 volt
three phase or perhaps something else all together. Also provide the
configuration and voltage of the buildings power system.
sounds like your description of delta 3 phase with the neutral tap on
one leg. From the way it was described to me, one leg measures 220 and
the other two measure 110. Does this sound correct?
The machPhase: 3
Wire: 3
Volt: 220
Cycle: 60 Hz
Load: 37.0 KVA
It came from an auction and apparently it originally had a box
containing transformers that were sold seperately.
Does the nameplate describe the power requirements? Also is it easy to
measure the source? I can check with a voltmeter. Thanks a lot for
the help.
Dan
The problem that you have, if any, is that the voltage of the equipment is 220v
and not 240v. Normally this is not a problem, but since it is CNC equipment it
could be. Usually
this occurs if the equipment is rated 208v.
You will need to obtain 3 buck/boost transformers or find a vendor that produces
one in one enclosure.
Your description sounds like your supply is 3 wire like this
/- 240V -\
A - 120V - N - 120V - B with 3 wires: A, B, N
then your supply is single phase.
Looks like the lathe requires 3 phase that is supplied as a delta (as
Don said it the machine doesn't require a delta, but that is how 240V is
normally supplied). Essentially repeating from the post above, if you
measure voltage between any 2 of 3 hots it should be 240V (there are 3
measurements).
Deltas mostly have the center point one one side as the neutral and
grounded. From 2 of the hots to neutral the voltage is 120V. From the
3rd hot to neutral the voltage is 208V - the high leg, orange wire, B
phase in but old panels.
3 phase 3 wire shouldn't require a neutral.
It is possible the transformers were necessary but I would doubt it.
There should be terminal bars for transformer connection if they are
required. There should be a control transformer to supply relays and the
numerical control. Be careful - with not a lot of effort the computer
control could wind up fried.
Might be worth asking the repairman what he was talking about now that
you are a 3 phase expert.
My understanding of the difference between 240V and 220V is that 240V is
nominal at the supply (service) and 220V is nominal at the load. The
lathe manufacturer sounds non-US which may be different.
bud--
Taking the obvious step of Googling Mori Seki turned up
Mori Seki - US
formatting link
Mori Seki - world
formatting link
likely know about them, but just in case...
-------------------
Warning - way of topic - some may be interested in
Googling "failure" using "I'm feeling lucky"
bud--
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