NEED HELP WITH VFD/MOTOR

[Jraef]

So why are you so worried about this? 150 degrees on an AC motor is nothing to get excited about. Sure, it's a lot more than the other motor, but do you know for ABSOLUTE SURE that the applications are EXACTLY the same in every possible way? For instance, is the cool motor pump output FEEDING into the hotter motor intake? If so, you would have some heat gain in the fluid itself that might be transmitting. Could be any number of unknowns like that.

Most basic motors now will come with at least Class F insulation, which means they are good for 155 degree C (311 degrees F), as a maximum temperature at which you can expect 20,000 hours of operating life at. If it has Class H insulation, it's even higher than that. With the OUTER case temperature being 150F, about 65C, you can assume the windings might be 10C hotter, so 75C maybe. That means even at Class F you are STILL looking at in excess of 100,000 hours of life, which is 24/7/365 for over 11 years, who knows how long if it occasionally gets turned off. Is that a problem for you?

Again, check to make sure someone has not tweaked the carrier frequency and if it is not EXACTLY the same as the other drives, make it so. Then hit it with a vibration analyzer and if it's OK, no serious side bands, I wouldn't waste a lot more thought on it.

 

[bure961]

Jraef, all good information for me . Thanks for all you help.

 

[Besoeker]

Correct, I myself may swap drives around before swapping motors - seems like it would be less labor intensive, and those motors are never on grade level with easy access for simple material handling equipment. The drives may all be in same control room - maybe even an air conditioned room:thumbsup:, one may not even need to move drives just re-route conductors.

Good thinking. Different approach. Same idea. Especially if it can be done by just rerouting the power conductors.
But what about controls? Push a remote start button and the wrong motor runs?

That's why I would go for the motor swap. And it isn't such a big motor.

 

[kwired]

Good thinking. Different approach. Same idea. Especially if it can be done by just rerouting the power conductors.
But what about controls? Push a remote start button and the wrong motor runs?

That's why I would go for the motor swap. And it isn't such a big motor.

Compared to what some people run into, correct it is not a big motor.

It is big in comparison to 10hp and below motors, and is much more likely to require additional equipment just to lift the motor.

Most of what I work on 200 hp is a big motor, and always is/has been a much bigger job to install/remove the motor then it is for applications using 10 HP or below.

If you are swapping power conductors why wouldn't you also swap control conductors so that you keep consistency in the control scheme? Maybe some applications where you could get away with out switching contols, but most times you would want to.

 

[Besoeker]

Compared to what some people run into, correct it is not a big motor.

It is big in comparison to 10hp and below motors, and is much more likely to require additional equipment just to lift the motor.

Most of what I work on 200 hp is a big motor, and always is/has been a much bigger job to install/remove the motor then it is for applications using 10 HP or below.

If you are swapping power conductors why wouldn't you also swap control conductors so that you keep consistency in the control scheme? Maybe some applications where you could get away with out switching contols, but most times you would want to.

Greater risk of errors the more conductors you have to move.