Electric Motors


I need to know about the efficiency of 3 phase electric motor where i have only input voltage,current,frequency & rpm.

What is the formula to find the efficiency?

asked 12/14/2016

3 Answers

an electric motor is an electrical machine thats convert electrical energy to mechanical energy most electric motors  operate through the interaction between the motors magnetic field and winding currents to generate force in the form of rotation
answered 1 week ago rajkishor 2

Po(power out)
Pi(power in)

thus, if you have the rating of the power delivered you just divide it and get your efficiency 

OR can use the following 

E=(746*HP)/[(746*HP)+(watts lost)] Where 746 is a constant and HP=horsepower

just my two humble cents, hope this helps

answered 4 months ago Expeditions Conquistador 2
Expeditions Conquistador
i think by using the relation of the losses so we can find the losses and subtract the losses we get output .
i think it is correct .we can get an appropriate efficiency. if wrong forgive me sir .
and please tell me the solution sir.
thank you
answered 12/30/2016 Thulasi 2

Your Answer

In order to provide an answer to this question, you must Login

I am flagging this question because...

10 inform moderator flags remaining

I am deleting this question because...

I am flagging this answer because...

10 inform moderator flags remaining

Flagging a Post

You have already flagged this post. Clicking "Remove Flag" below will remove your flag, thus reducing the count by one as well.

I am deleting this answer because...

Aluminium Windings - Dry Type Transformers

The other day I was talking to a colleague who is a building services consultant.  Despite regularly specifying dry-type/cast resin transformers he was...

Battery Cars A to Z

Battery powered cars are a hot topic and widely debated. The pros, cons, issues and time frames can be talked about endlessly. An article by the Telegraph...

UPS - Uninterruptible Power Supply

A UPS is an uninterruptible power supply.  It is a device which maintains a continuous supply of electrical power, even in the event of failure of the...

IEC Document Designation

Often document control is dictated by project requirements, for example a particular organisation may have an existing numbering system. Existing company...


A battery consists of one or more cells, each of which use stored chemical energy to produce electrical energy, There are many types of cells and these...

Alternating Current Circuits

Alternating current (a.c.) is the backbone of modern electrical power distribution. In this article I’ll be pulling some of the more important concepts...

Power Factor

Power factor is the ratio between the real power (P in kW) and apparent power (S in kVA) drawn by an electrical load. The reactive power (Q in kVAr)...

Network Theory – Introduction and Review

In electrical engineering, Network Theory is the study of how to solve circuit problems. By analyzing circuits, the engineer looks to determine the various...

Wiki Depreciation

We have had the Wiki with us for a long time now, but at last I have decided to say bye bye – more details on why below.

Fire Resistant and Fire Retardant Cables

Fire resistant and fire retardant cable sheaths are design to resist combustion and limit the propagation of flames. Low smokes cables have a sheath designed...

Our website uses cookies so that we can provide a better experience.
To learn more about what cookies are and how to manage them visit AboutCookies.org