Wegner Crane CFW500 series Applications Manual - page 65
Parameters Description
Crane | 65
Description of the identified moments:
1 – The load forward command is given through the digital input DI1. The motor becomes magnetized, and
voltage and frequency are applied to it. The brake remains closed.
2 – The motor frequency reaches the threshold adjusted in P1041 and the command to release the mechanical
brake through the digital output DO1 is executed. Momentary overload detection delay time, programmed in
P1053, starts elapsing because the load forward and brake release commands are presented.
3 – With the brake release, the load forward with the speed reference 1 adjusted in P1031 begins.
4 – The overweight detection delay time has elapsed.
5 – The motor current is greater than the overweight threshold programmed in P1052, the momentary overload
alarm delay timer begins counting the time programmed in P1054.
6 – The overweight alarm delay time has elapsed and the alarm “A770: Momentary Overload”, is generated. The
crane horizontal motion continues to operate normally.
7 – The value of motor current is less than the value adjusted to momentary overload current threshold in P1052
and the momentary overload alarm condition is normalized. The crane horizontal motion continues to operate
normally
8 – The load forward command is removed from the digital input DI1. The motor deceleration begins. The brake
remains release.
9 – The motor frequency becomes less than or equal to the threshold adjusted in P1048, and the command to
close the mechanical brake is executed through the removal of the digital output DO1 command.
10 – The motor is decelerated down to 0 Hz and remains magnetized (If within the period programmed in
P1027 a new load forward or load reverse command does not occur, the motor will be demagnetized). The load
remains stopped, being held by the mechanical brake.
3.15 SLACK CABLE (VERTICAL)
This parameter group allows the user to adjust the conditions for the crane vertical motion slack cable detection
during the load lowering stage.
Slack cable is an abnormal condition detected during the lowering stage of the crane vertical motion, by the
verification of load existence.
NOTE!
The weight of the load is not measured directly, in other words, the load is detected observing the
behavior of the motor controlled by the CFW500 frequency inverter. It is known that while being
lowered, the load is usually braked by the motor, which regenerates energy to the inverter. If instead
of braking the load, the motor is actually driving the hoist down, this would indicate load absence
.
P1055 – Load Detection Time
Adjustable
0.00 to 650.00 s
Factory Setting: 0.75 s
Range:
Proprieties:
Access groups via HMI:
SPLC
Description:
This parameter defines a period with the motor regenerating energy after the lowering command has been
given, before initiating the slack cable monitoring.