Difference in kw

lokesh.dee · Apr 7, 2014

Hi

we have a 50 h p motor driving a agittaor thru gear box 50 hp 1500:155 rpm ration rpm.
Frequency drive is dranfoss we are monitoring the power drwan by the motor is very less at 100% load.

The readings are as below at 100%

v 390 v

kw 19

amps 34

rpm 1470

motor name plate details

v 380 v

hp 50

amps 59

rpm 1460

telectrix · Apr 7, 2014

50hp does not equate to 19kW. something is not right here.

Deleted member 72666 · Apr 7, 2014

Don't forget your running at unity pf! (Not done the calcs as icba.)

plugsandsparks · Apr 7, 2014

I think the info you have from the inverter does not demonstrate 100% load, maybe 100% speed. Numbers look about right for a motor NOT at full load.

Marvo · Apr 7, 2014

How are you measuring the running current?

As Telectrix points out the kW rating and HP you give for your motor don't add up. A 50 HP motor would nominally be around 37kW.

Simonslimline · Apr 7, 2014

50 x 745.7 watts equals 37.285 Kw

37285 /1.732 x 380 x 0.96 equals 59A

Why does it say 19Kw !

Knobhead · Apr 7, 2014

I’ll leave it to you lot, I’ve tried getting information out of him before. It’s a long protracted process. If you’re lucky you get a clue a day.

lokesh.dee · Apr 7, 2014

Thank you

speed is 100% the mechanical load is agitation of 4.5-5 K L liquid in 5 K L tank.it is fermenter.

lokesh.dee · Apr 7, 2014

thank you

i also confused

lokesh.dee · Apr 7, 2014

the current and all other reading i given from Frequency drive display

lokesh.dee · Apr 7, 2014

hi tony

this is different post than other

Darkwood · Apr 8, 2014

Is the drive set up correctly?
How does the drive monitor speed? (Open/closed loop). This may account for
Can you take a pic of the motor plate and post...

As above the readings you list sound like the readings off the drive while running so 19KW reflects the power usage while running and not what the motor is capable of at full load. What is the KW rating of the drive written on the rating label somewhere about the drive?

lokesh.dee · Apr 8, 2014

Thank you sparks

if motor speed is 100% does not it mean 100% load. Then how can we measure the load???!!as i told the mechanical load is agitation for fermentation process if quantity or sp gravity increases load will increse??