Motor Power Factor
Motor Power Factor
(OP)
Does using a larger motor for the same load cause it to run at a lower power factor and result in a lower power consumption. If so what are the disadvantages of doing this which deter it from being a common practice.





RE: Motor Power Factor
http://www.turi.org/PDF/Chap%203%20-%20Motors.pdf
for a motor performance as a function of load
RE: Motor Power Factor
RE: Motor Power Factor
The core will be larger and more reactive magnetizing current required.
The real power output is determined by the load and will not change.
There are some losses within the motor which affect efficiency. With larger than required motor, portions of those losses will go up (core losses), and portions of those losses may go down (I^2*R losses... depending upon winding). Maybe someone else can comment which direction efficiency will go but I'm not sure.
Of course a big factor is initial cost. Larger than required motor will cost more. Usually motor is sized some margin above expected load to allow for errors in calculation and possible future change in loading.
RE: Motor Power Factor
RE: Motor Power Factor
RE: Motor Power Factor
1) pf tends to go down from the same manufacturer for the same horsepower rating as the numbers of poles increase, that's to say, from 2,4,6, 8 ...so on, the pf drops, can some one explain pls,
2) is it true that from the same manufacturer/manufacturing technique & design and same pole numbers, for a given horsepower rating say 200 hp, the pf is lower for a submersible motor (IP 68) direct coupled to submersible sewerage pump compared to the same motor rating of TEFC type from the same manufacturer,
Lastly, appreciate if you all out there can advise how to improve the pf of submerged motor to that of TEFC motor form the same manufacturer, and what's the IP rating possible with TEFC motors.
Cheers
Jyaces1
RE: Motor Power Factor