Service Factor - WEG SSW-07 Manual Del Usuario

CALL NOW 800-985-6929

5.2.2 Service Factor

CALL NOW 800-985-6929
http://www.automatedpt.com/
Chapter 5 - prOGraMMING INFOrMatION aND SUGGeStIONS
NOTE!
Remember that this protection has as a standard the Three Phase
IP55 Standard WEG Motor, therefore if your motor is different, then
do not program the thermal class to its maximum, instead, program
it near its minimum thermal class to start.
Example of how setting the thermal class:
Motor data:
Power: 50 hp
Voltage: 380 V
Nominal Current (ln): 71 A
Service Factor (S.F.): 1.00
lp/ln: 6.6
Stall time: 12 s in hot condition
Speed: 1770 rpm
Motor + load starting data:
Starting by Voltage Ramp, starting current average:
3 x the nominal current of the motor during 17 s (3 x ln @ 17 s).
1) In the graph, figure 4.8 in cold condition, one can see the minimum
Thermal Class that will allow the start with a reduced voltage:
For 3 x ln of the motor @17 s, the next highest is adopted: Class 10.
2) In the graph, figure 4.9 in hot condition, one can see the maximum
Thermal Class that the motor can stand due to the stall time in hot
condition:
For 6.6 x ln of the motor @ 12 s, the next lowest is adopted. Class 30.
One now knows that Thermal Class 10 allows a start and Thermal
Class 30 is the maximum limit. Thus, a Thermal Class between the
two should be adopted, according to the quantity of starts per hour
and the interval of time between Off/On procedures the motor.
The closer to Class 10, the more protected the motor will be, the
fewer the starts per hour and the greater the interval of time must
be between Off/On procedures the motor.
The closer to Class 30, the closer it gets to the maximum limit of the
motor, thus there can be more starts per hour and lower intervals of
time between Off/On procedures the motor.
When the Service Factor (S.F.) is different from 1.00 and if there is
the need to use it in the application, this must be considered in the
setting of the overload protection. To avoid tripping of the overload
protection, when the service factor is used, the nominal motor current
set at the SSW-07 must be readjusted. If an acessorie with parameter
access is used, the service factor can be set directly in the P406,
avoiding the readjustment of the nominal currrent.
http://www.automatedpt.com/
Email: charles@automatedpt.com
45
Email: charles@automatedpt.com