Motor Brake Slip Detection (Clv) - Hitachi P1 Basic Instruction Manual

MOTOR BRAKE SLIP DETECTION (CLV)

Motor brake slip detection is safety check feature that checks to make sure the motor brake can hold the suspended load at the end
of each lift cycle prior to removing complete power from the motor. This is safety check feature is only available when operating in
closed loop vector control only (AA121 = 10).
HOW IT WORKS – At the end of a lift cycle and when the load float time expires the motor brake will be commanded to close. Once
the motor brake closes and the brake delay set time has expired the test will begin. The VFD will start to controllably limit the output
torque to the motor while checking for movement on the motor shaft via the encoder signal. If a slip is detected the VFD will restore
the torque limiter back to the default value and hold the load at 0hz / 0 speed, any digital outputs configured for 75:M07 will turn on
for brake slip detection indication, and the hoist up and high-speed function will be disabled and only hoist down will be allowed.
Once the test passes either by lower the load to the ground or removing the weight the VFD will trip with a E50 fault code to indicate
a brake slip was detected and the motor brake should be inspected immediately!
IMPORTANT! – If a brake slip is detected do not turn off power or load may fall, inspect motor brake immediately!
IMPORTANT! – Disabling this feature is not recommended unless troubleshooting without a load. Disabling this safety check feature
with a load suspended may result in dropping of the load.
TROUBLESHOOTING E50 – If an E50 fault occurs check the motor brake immediately. If the motor brake is verified, then check for
electromagnetically induced signals on the encoder line, if there is induced signals try adding a ferrite core magnet double wrapped
around the encoder wire. Verify the encoder wire shield or drain wire is terminated to a ground source. If the motor brake is delayed
and is casing premature trips, then increase the motor brake delay set time.
Function
Motor Brake Slip Detection Test
Motor Brake Slip Detection Max Pulse Count
IMPORTANT! - Increasing the detection pulse count can result in a delayed detection or no detecting and load my fall.
Motor Brake Slip Detection Torque
Reduction Time
Motor Brake Slip Detection Output Signal
Parameters
UE-34
UE-35
UE-37
CC-03 – CC-06
CC-03 (factory default)
Page 26
Value
0 = Disabled
1 = Enabled
5 pulses (default)
15
(0.15 seconds default)
75:MO7