WEG CFW-11 Series, Programming Manual, Page: 225 / 307

15-5
15
Faults and Alarms
Description:
These parameters are used for the motor overload protection (I x t – F072).
The motor overload current (P0156, P0157 and P0158) is the value from which the inverter starts considering that
the motor is operating with overload.
The bigger the difference between the motor current and the overload current, the faster F072 trip will occur.
When P0202 = 6 or 7 (Sensorless Vector Control or Vector Control with Encoder, both for PM motor) and P0406 = 0
(Self-ventilated Motor), the parameters P0156, P0157 and P0158 must be adjusted 5 % higher than the motor rated
current (P0401).
The parameters P0156, P0157 and P0158 are adjusted automatically when P0401 (Motor Rated Current), P0406
(Motor Ventilation Type) or P0298 (Inverter Application) are set during the "Oriented Start-up" routine (refer to this
parameter description in the section 11.7 – Motor Data of CFW-11 Programming Manual V3.1X).
The overload current is given as a function of the speed being applied to the motor, according to the overload
curve. The parameter P0156, P0157 and P0158 are the three points used to form the motor overload curve, as
presented in the
Figure 15.2 on page 15-5 .
% Rated Speed
% P0401
P0156
0 5 50 100
110
105
100
98
90
65
0
P0157
Curve for a motor with separated ventilation
Curve for a Self-ventilated motor
P0158
Figure 15.2 - Overload protection levels
With the setting of the overload current curve, it is possible to set an overload value that varies according to the
operation speed of the motor (factory setting), improving the protection for self-ventilated motors, or a constant
overload level for any speed applied to the motor (motors with separated ventilation).
This curve is adjusted automatically when P0406 (Motor Ventilation Type) is set during the "Oriented Start-up" routine
(refer to this parameter description in the
Section 11.7 MOTOR DATA [43] on page 11-10 ).