WEG CFW-11 Programming Manual page 204

Faults and Alarms
P0159 – Motor thermal class
Adjustable
Range:
Proprieties:
Access groups
via HMI:
Description:
This parameter sets the motor thermal class, and the time for the correct actuation of the F072 fault depends on it.
The higher the thermal class, the longer the fault actuation time will be.
atteNtioN!
The incorrect selection of the thermal class may cause the burning of the motor.
atteNtioN!
In order that the CFW-11 motor overload protection be in conformity with the UL508C standard, use
a tripping class ≤ 20 (P0159 ≤ 3).
The necessary data for choosing the thermal class are the following:
- Motor rated current (I
- Blocked rotor current (I
- Blocked rotor time (T
- Service factor (SF).
* Note.: It must be verified if the given blocked rotor time is for hot or cold motor, so that the correspondent thermal
class curves be used.
With those values, the overload current and the overload time must be calculated using the following equations:
These equations provide the limit conditions for the error actuation, i.e., the motor cannot work with a longer fault
15
actuation time than this one, because of burning risk. Thus, a thermal class immediately inferior must be chosen so
that the motor protection is assured.
15-6
0 = Class 5
1 = Class 10
2 = Class 15
3 = Class 20
4 = Class 25
5 = Class 30
6 = Class 35
7 = Class 40
8 = Class 45
CFG
01 PARAMETER GROUPS
45 Protections
);
n
);
p
)*;
BR
Overload Current =
Overload Time = T
I
p
x 100 (%)
I x SF
n
(s)
BR
Factory 1
Setting: