iam stuck in a gruesome situation..have placed orders for some heavy
duty wood working machinery from US.Most of these involve 3ph,220v,60hz
motors but i need to operate them at 220v,3ph,50hz supply.
can anyone please advice me on what will happen to the production(
efficiency wise.) in this case.
eagerly waiting for ur help..
thnks a ton.
You would loose 20% in speed. But most important, most of the 60Hz
motors are not build for running permanently on 50Hz (too little iron),
so they will overheat.
Possible solutions: Frequency converter (this way you will have an
electronic speed adjustment) or change the motors.
Good News and more good news. The machines will most likely work just
fine on 50Hz. If these are 3 phase machines they are most likely common
squirrel cage induction motors. Three phase induction motors are
frequently powered with variable frequency AC drives at less than base
speed (60 Hz in your case) with no damage or overheating. Yes the speed
will be 16.6% slower, but I doubt you will notice any difference. The
motor will see full mains voltage at 50Hz and will effectively be
operating slightly overvoltage, this also will most likely not be an
issue with only a slight increase in the no load mag current of the
stator windings. Most induction motors are designed to tolerate up to a
20% variance in line voltage. I would be much more concerned if you were
operating in an undervoltage condition, which will definitely fry your
motor slowly. If the equipment includes any control transformers or
starters/contactors then 50Hz may damage the transformers or coil
windings if they are not dual frequency rated. Any electronic controls
are also a concern and probably beyond the scope of discussion on the
newsgroup without specific controller data from the manufacturer.
> hi all..
> iam stuck in a gruesome situation..have placed orders for some heavy
> duty wood working machinery from US.Most of these involve 3ph,220v,60hz
> motors but i need to operate them at 220v,3ph,50hz supply.
> can anyone please advice me on what will happen to the production(
> efficiency wise.) in this case.
> eagerly waiting for ur help..
> thnks a ton.
You have a problem.
60Hz motors will fail if operated at load with 50Hz power.
You need to buy 50Hz replacement motors.
Why not order the correct motors from whomever you are ordering your
equipment from, most major manufacturers provide motors in various phase and
voltage configurations and probably in both frequencies. This way they will
have the correct size pulleys and belts to provide the proper working speed
for each tool.
On 23 May 2006 02:19:30 -0700, email@example.com wrote:
It'll be fine. They _will_ work. They _will_ run slower.
-- Unless they're actually US made, where some of the makers have been
known to under-size laminations so that they only achieved their full
rated power when run on 60Hz. At frequencies below this the lower
frequency was less magnetically efficient and caused higher losses.
Fortunately the days America doesn't make anything any more and your
motors are probably Chinese -- the Chinese appreciate world markets and
design motors appropriately.
60 Hz motors all work at 50Hz. As the limit on motor power is basically
the acceptable temperature rise when under full load, the only effect of
moving from 60Hz to 50Hz on _any_ motor is at worst a reduced maximum
output power available. It's rare that you run motors in this region and
it's more likely that a high ambient temperature and poor colling would
be causing you more trouble anyway.
A frequency converting inverter will cost far more than a new motor and
is only sensible if you also need the variable speed feature. It's also
quite liekly to make the motors run _hotter_. If the inverter's output
isn't a smooth sine wave (and quality output costs real money) then the
extra high frequency harmonics in the output will cause more excess
heating than the frequency drop ever did.
Assuming you specified motors that can run on 50 hz (It is not unusual
for motors to be rated for both) they will run at about 83% of the
of their 60 hz rated speed when running at 50hz. Whether that is a
problem or not would depend on the specific application. If the motors
are NOT rated for 50 hz operation, they will run hot, though perhaps
on a lightly loaded machine you could be OK.
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