Efficiency of Induction Motor

Says who?

In my books the efficiency is maximum when there is no losses!

I believe that the motor efficiency is given by output shaft power divided by input electrical power. So if you are trying to be "cute" and imply when not running the efficiency is highest, you now have a troublesome division, with 0 being divided by 0.

So I must ask if you have developed such a motor? (one with no losses) If so, there is a spot for you on YouTube, right along side of the internal combustion motor that breaks down water into hydrogen and oxygen, burns it, and outputs more power than input.

It's like everyone forgets about L'Hôpital's rule once they leave school.

Make me go back 40 years. I first learned of L'Hôpital's rule in a class taught by a French mathematician. Neat huh? Can't remember his name, but that accent - never will forget that. It was not classic Inspector Clouseau, as he was from the Brittany region. Seems they have regional dialects over there too.

Now if I'm not mistaken, the rule applies to functions tending to 0 in the limit, not to a hard number 0. What we have here is an absolute absence of power divided by an absolute absence of power, not a function of power tending to 0.... you get the idea.

Maximum efficiency is reached when power in = power out....

or...

http://www.electrical4u.com/losses-and-efficiency-of-induction-motor/

There is no such thing as a constant loss. If there were then an induction motor would draw power from something all the time, even while disconnected from a power source.

Nonsense.

A constant is just that, constant, without variation. A variation is not constant by its very nature. Ergo, the statement above is incomplete and not true. Both variation loss and constant loss is output and two calculation may be required to find a mean average.

Efficiency is defined as the ratio of the output to that of input,

Three phase induction motor efficiency,