Faults And Alarms; Motor Overload Protection (F072 And A046) - WEG CFW100 Programming Manual

13 FAULTS AND ALARMS

The problem detection structure in the inverter is based on the fault and alarm indication.
In case of fault, the locking the IGBTs and motor stop by inertia will occur.
The alarm works as a warning for the user of critical operating conditions and that may cause a fault if the situation
is not corrected.
Refer to chapter 6 of the CFW100 user manual and the
AND FAULTS on page 0-1

13.1 MOTOR OVERLOAD PROTECTION (F072 AND A046)

The motor overload protection is based on the use of curves that simulate the heating and cooling of the motor in
cases of overload. The motor overload protection fault and alarm codes are F072 and A046 respectively.
The motor overload is given considering the reference value In x FS (motor rated current multiplied by the duty
factor), which is the maximum value at which the overload protection must not actuate, because the motor can
work continuously at that current value without damages.
However, for that protection to actuate properly, the winding-temperature supervision (which corresponds to the
time of heating and cooling of the motor) is estimated.
This winding-temperature supervision is approximated by a function called Ixt, which integrates the output current
value from a level previously defined by P156. When the accumulated value reaches the limit, an alarm and/or
fault are indicated
In order to ensure greater protection in case of restart, this function keeps the value integrated by the function
lxt in the inverter non-volatile memory. Thus, after the energizing, the function will use the Ixt value saved in this
memory to perform a new evaluation of overload.
P156 – Overload Current
Adjustable
0.1 to 2xI
Range:
Properties:
Description:
These parameters define the motor overload current (Ixt - F072). The motor overload current is the current value
(P156) based on which the inverter will understand that the motor is operating in overload
The greater the difference between the motor current and the overload current (P156) the faster the actuation
of fault F072.
It is recommended that parameter P156 (motor overload current at rated speed) be set at a value 10 % above
the used motor rated current (P401).
In order to deactivate the motor overload function just set parameters P156 to values equal to or above two
times the inverter rated current P295.
Figure 13.1 on page 13-2
relation to the overload current (P156), that is, for a constant output current with 150 % of overload, fault
F072 occurs in 60 seconds. On the other hand, for output current value below P156, according to the output
frequency, fault F072 does not occur. Whereas for values above 150 % of P156 the fault actuation time is below
60 s.
of this manual to obtain more information regarding Faults and Alarms.
nom
shows the overload actuation time considering the normalized output current in
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Faults and Alarms
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P156 =
Setting: 1.2xI
nom
CFW100 | 13-1
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