Crompton Greaves Induction Motor Data

Is the motor efficiency stated on the nameplate? Is the power factor (or cos phi) stated? Most 415 volt systems are in SI countries, so why does the nameplate specify hp?

The FLA will vary according to rpm, due to efficiency losses....

http://www.roycecross.com.au/documents/manualsPDF/CG%20THREE%20PHASE%20CATALOGUE.pdf

the efficiency at full load is: 86% and rpm is 950 as mentioned in the nameplate,

Regs,

Is there an echo in the room?

sorry, 85% full load efficiency, frame 132M, ambient 50 degree centigrade, RPM 950.

Regs,

Yes, you should have divided by that as well to get FLC. Rpm does not affect current.

taking the value of efficiency as 0.861048 gives FLC of 11.30 Amp, but with 85% efficiency, we get FLC as 11.447 Amps. Is there adjustment for ambient temperature of 50 degree centigrade?

Regs,

At this point, I think you are 'splitting hairs'.

• "...taking the value of efficiency as 0.861048 gives FLC of 11.30 Amp, but with 85% efficiency, we get FLC as 11.447 Amps. Is there adjustment for ambient temperature of 50 degree centigrade?"
• "At this point, I think you are 'splitting hairs'."
  

Working so hard to account for 0.147A out of 11.447A is in my opinion more like splitting the split ends of hairs... This should be nominated for being the defining statement in describing "anal retentive" for the year.

That level (1.28417926094173%) of exactitude can be more than accounted for by measurement error.

Not that I'm aware of, but you might look on the internet. It's not an exact science, definitely not to 6 decimal places!

I agree with #9. One minute you're wondering why it's 11.3 amp, not 9.73, next you're querying 1 percentage point.

I want to see how that guy above sets a thermal relay with a precsion around 1 mA. :)

Neither the motor current nor the settings of conventional thermal motor protection relays is very precise, let allow a +/- couple of % and surrounding temperature play a role too.

The above link for induction motor from Crompton Greaves showsFrame size too. It is mentioned in the catalog as: 63 to 400 for TEFC.

But in my motor nameplate rating, Frame has been defined as MD132M and BPM123M. How to interpret this?

Regs,

The 123 is a typo. The prefix letters may designate items such as extended or stepped shafts, such as used for some types of pumps. They have little or no effect on amperage characteristics.

Is it FLC or Staring Current?. I would like to what is the problem in the performance of the motor?. Is it getting heated up?. We have used similar size motors suitable for Crane Duty and they have worked well without any problem. Crompton is well known and reliable make.