Overloading of S1 Duty Motor

if its really an S1 its continuously duty rated

1) Maximum nameplate current rating. Overloading a motor continuously will cause it to prematurely fail.

2) No, it is not a good idea to further overload the motor at 130%.

Since the motor is already experiencing a 120% overload condition I would suggest you purchase a new motor large enough rated to handle the increased load if you want the equipment to operate reliably.

It would be best for you to contact the Original Equipment Manufacturer of the motor and ask them your questions if you want to be absolutely sure.

You should monitor temperature, that's the bottom line....class 'B' insulation I think is good for 20k hrs @120°C....

http://www.pdhonline.org/courses/e156/e156content.pdf

https://www.youtube.com/watch?v=cMG2hTac39M

What is the service factor of the motor?

This should be on the nameplate.

93°C is not too hot.

You can run the motor at 130% load if you want.

Even 150% load may be OK.

You won't know until you try it.

Let us know how it works out for you.

Lyn, for motors in the IEC world there is no such thing as "Service Factor" as we know it in NEMA world. All of their motor designs are what we would consider a 1.0SF, with the possible exception of S9. All the rest of their design designations, S2 -S8, are variations of what we would call "intermittent duty", S1 is continuous duty, but no Service Factor at all.

Thanks. Yes, I lived/worked in the NEMA world.

Looking at his operating temperature it would seem the motor is not being overworked.

Are the materials used in the motor winding made according isolation class B (max 130°C) and is the temperature rise in de motor limited to a temperature rising according class B (50 to 130 gives an allowed temperature rise from 80°C)?

Or

Are the materials used in the motor winding made according isolation class F (max 155°C) and is the temperature rise in the motor limited to a temperature rise according class B (50 to 150 gives an allowed temperature rise from 100°C)?

In this latter case, you have a much more safety margin.

For this application you should select S4 duty motor. Sorry no overloading permitted on such motors.

I agree with suresh Sharma. The actual duty has to be S10.

In my opinion, if no pause is expected- the motor operates continuously in this cycle-no overload is permitted. If I1=120% within 130 sec and I2=65% within 130 sec the average current Iav=sqrt((I1^2*t1+I2^2*t2)/(t1+t2)) is 96.5%

Thanks to all for your valuable feedbacks

If it were allowable then, logically, it wouldn't be an overload! Thanks for this post, for it has considerable amusement value. Do keep a list of motor suppliers and some fire extinguishers to hand, for they will inevitably be needed.

Duty cycle is related to the number of starts per hour, It has nothing to do with overloading the motor. You will need to use the correct KW motor to stop the motor from overloading and select the correct duty cycle to prevent premature failure.