IMPULSE•VG+ Series 3 Instruction Manual – 07/25/05
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If the memorized value is less than the programmed value in C8-03 (Minimum Brake Release
torque), then C8-03 is used as the next brake release value. If the feature must be disabled, C8-03
will override C8-16 if it is a greater value than C8-16.
Once the brake has been commanded to release, the output remains in Load Float for the amount of
time programmed into C8-04. During C8-04, the drive waits for the brake to completely open and
watches encoder feedback. If the amount of feedback is less than the setting in C8-05 (Roll Back
Count), then the drive proceeds to the BE3 check. If it is not, a BE1 alarm is displayed on the keypad
and the sequence stops. For the BE3 check, if the brake opened mechanically, then the encoder
feedback must be greater than or equal to the value programmed in C8-07 (BE3 Detect Count)
within the time set in C8-06 (BE3/Alternate Torque Time). If it is not, then BE3 is displayed. By the
time the drive has completed the BE3 check, there should be a significant amount of motor shaft
movement and the NLB start sequence is complete.
The NLB Stop Sequence begins when the run command has been removed and the output frequency
has decelerated to zero. Once at zero speed, the motor maintains a Load Float position for the
duration of C8-10 (Load Float Time). During the Load Float time, run commands in either direction
are accepted and will begin accelerating immediately in the commanded direction thereby skipping
the NLB Start Sequence entirely. The Load Float Timer is reset after each new run command. Once
the Load Float Timer expires, the brake output command is removed (thereby closing the brake) and
Zero Servo is maintained for the time set in C8-11 (Brake Delay Time) to allow the brake to fully
close. Once the Brake Delay Time has expired, the BE6 check is executed. The BE6 check monitors
encoder feedback and compares it to C8-13 (BE6 Max count). The encoder feedback must not
exceed the number of counts in C8-13 within the C8-12 (BE6 Detect Timer) time. If it does
(meaning the load slipped through the brake), a BE6 alarm is displayed on the keypad and the drive
will reset its zero servo position and maintain its new position. Run commands will still be accepted
with the exception of a reduced speed in the up direction set by C8-17 (BE6 Up speed) and the NLB
stop sequence will begin again once the run command had been removed.
NOTE: All brake faults are annunciated by both the keypad, and via a programmed digital
output. Since the keypad is not visible by the operator, an external warning device must be
used to ensure proper safety of personnel and equipment. Annunciating a brake fault can be
accomplished by using one, or both, of the following methods. 1) An indicating or strobe light
that is continuously “ON”, indicating proper operation. If the light should turn “OFF”, this
indicates that the light bulb has either burned out, or there is a drive or brake problem. Either
scenario requires immediate corrective action. The use of an indicating light wired to relay
output terminals MC-MB, a N/C contact, an audible warning device that will sound during a
brake fault condition. A 120 VAC audible warning device can be wired directly to terminals
MC-MA, provided that it’s ratings do not exceed the 1 Amp, 120 VAC, Inductive.
If a brake fault is annunciated during a “Start” sequence, it is recommended that the crane be
moved to a safe location with the load on the hook. The hoist should only be operated if
absolutely necessary. In this type of alarm sequence, either the brake is seized or the drive
cannot develop enough torque in the motor in the time allotted. To troubleshoot the hoist it will
be necessary to monitor the keypad on the drive and operate the hoist at the same time. Two
people are recommended for this procedure. With one person operating the hoist and the other
person monitoring the keypad, run the hoist. The keypad should display one of the following
alarms: BE1, BE2, BE3, BE4. For corrective action, refer to “Troubleshooting the Drive” in
Chapter 6 of this manual.
If a brake fault is annunciated after the hoist has come to a complete stop, and Load Float (C8-
10) has timed out, it would indicate that the drive has checked the brake and determined that
the brake has insufficient torque available to hold the load, DO NOT TURN OFF POWER.
Summary of Contents for IMPULSE VG+ Series 3
Page 1: ...Software 8001 X July 2005 Part Number 140 10257 Copyright 2005 Magnetek Instruction Manual...
Page 6: ...c h a p t e r 1 Introduction...
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Page 14: ...c h a p t e r 2 Installation...
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Page 24: ...c h a p t e r 3 Wiring...
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Page 40: ...c h a p t e r 4 Programming Basic Features...
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Page 54: ...c h a p t e r 5 Programming Advanced Features...
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Page 149: ...IMPULSE VG Series 3 Instruction Manual 07 25 05 5 96...
Page 150: ...Troubleshooting IMPULSE VG Series 3 c h a p t e r 6...
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Page 170: ...A p p e n d i x A IMPULSE VG Series 3 Parameter Listing...
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Page 183: ...IMPULSE VG Series 3 Instruction Manual 07 25 05 A 14...