Cos Phi Monitoring - Siemens SIMOCODE pro System Manual

5.4

Cos phi monitoring

Description
Cos phi monitoring monitors the load condition of inductive loads. The main
field of application is for asynchronous motors in 1-phase or 3-phase
networks with loads that fluctuate significantly. The power factor fluctuates
more than either the motor current or the active power does, particularly in
the low-end performance area of a motor. Therefore, power factor
monitoring is particularly suitable for distinguishing between non-load
operation and faults, e.g. a broken drive belt or drive shaft. If the set trip
level or warning level is undershot, a signal is generated or the motor is
switched off, depending upon the setting.
Cos phi from
Current/voltage
measuring module
1)
Hysteresis for voltage, cos phi, power
(see "Voltage Monitoring" function block)
Fig. 5-5: "Cos Phi Monitoring" function block
Trip level, warning level
You can parameterize two different response levels (trip level/warning level)
for cos phi monitoring.
Trip level:
Warning level:
0 % = cos phi = 0.00
50 % = cos phi = 0.50
100 % = cos phi = 1.00
SIMOCODE pro
GWA 4NEB 631 6050- 22 DS 03
Cos phi monitoring
Trip level
Response
Delay
Warning level
Response
Delay
1)
Hysteresis
0 - 100 %
0 - 100 %
Monitoring functions
QE1
QE2
QE3
Tripping
QE4
QE5
See
Event
Table 5-9
- Trip level cos phi <
See
Event
Table 5-10
- Warning level cos phi <
5-11