Switching Frequency; Type Of Load Torque; Mechanical Characteristics; Mechanical Limit Speed - WEG Ex d Manual De Instalación, Operación Y Mantenimiento

3.1.3 SWITCHING FREQUENCY

The minimum switching frequency is 2,5 kHz.

3.1.4 TYPE OF LOAD TORQUE

For load with quadratic torque, motor can be operated at frequency range of 10% up to 100% of the rated
frequency if the load torque at the rated frequency is 95% of the motor rated torque.
For load with constant torque, motor can be operated at frequency range of 10% up to 100% of the rated
frequency if the load torque is lower than motor torque derating curve as showing below.
To operate at frequency above the rated frequency, use the derating curve and check if breakdown torque
is appropriate for the application in the maximum operating speed.
Note: For maximum motor speed selection, item 3.2.1. showing mechanical speed limits must be
considered.

3.2 MECHANICAL CHARACTERISTICS

3.2.1 MECHANICAL LIMIT SPEED

The mechanical limits speeds of the motor are indicated in the table following:
Frame
Motor
90 – 100
112
132
160
180
200
225
250
280
315
355
Note: For maximum motor speed selection, the derating curve of item 3.1.4 must be considered.
For other applications, please contact WEG.
- English -
2 pole 4 pole
7000
7000
6000
5000
4500
4000
3600
3600
3600
3600
3600
Part
Frequency
A 0.1 ≤ f/fr <0.25
B 0.25 ≤ f/fr <0.50
C
0.50 ≤ f/fr <0.83
D 0.83≤ f/fr ≤1.0
E
f/fr > 1.0
speed (rpm)
6 pole
7000 7000
6000 6000
5500 5500
5000 5000
4000 4000
3800 3800
3600 3600
3600 3600
3000 3000
2500 2500
1800 1800
INDUCTION MOTORS FOR HAZARDOUS AREAS | 11
Derating curve
Derating
Range
T = (f/fr) + 0.50
f
T = 0.4(f/fr) + 0.65
f
T = 0.3(f/fr) + 0.70
f
T = 0.95
f
T = 0.95 / (f/fr)
f
8 pole
7000
6000
5500
5000
4000
3800
3600
3600
3000
2500
1800