Troubleshooting E51 Fault - Hitachi P1 Basic Instruction Manual

TROUBLESHOOTING E51 FAULT

WHAT IS AN E51 FAULT - An E51 fault is a motor torque proving fault. The motor responded with less than the anticipated motor
current.
HOW IS AN E51 FAULT DETERMINED – When the VFD is operating in closed loop vector control only (AA121 = 10) at the start of a lift
cycle the VFD applies a calculated output torque to the motor and allows a specific amount of time UE-32 for the motor to respond
with the motor current. If the motor responds with less than the anticipated output current based on the torque to required current
calculation, then a motor torque proving fault is determined to have occurred.
•
If this fault is occurring at random it might be caused due to a high load or overload. If a high load or overload occurs it can
some�mes set a value in which the VFD & motor would need to prove a value higher than allowed. Check to make sure the
motor brake circuit is not dropping out randomly. Check to see if the encoder signal in unstable by using dA-08 detected
speed monitor, this value while run should be close to the set-frequency value. The allowable tolerance for dA-08 is + / -
1.5hz from the commanded frequency.
•
Check the physical condi�on of the motor brake pads and springs and make sure the VFD is not driving through the motor
brake during the test. Driving through the motor brake will cause the VFD to reduce the output torque to maintain the set-
frequency of 0 Hz.
•
Check that the motor brake air gap is within the required spec for that brake. Try adjus�ng it to the smallest air gap allowed
in the brake spec.
•
Check that the motor connec�ons are secure both at the VFD output terminals and at the motor junc�on box terminals.
• Check to see if the motor Io constant Hb116 was changed to a larger value than what's on the motor nameplate. Please not
in some cases this value in the drive may be lower due to service factor or duty cycle ra�ngs.
•
Make sure all loads are removed from the hook block and switch the VFD to an open loop control mode and see if the hoist
works properly and the output current isn't high and running smoothly. This will help determine if an IGBT output from the
VFD is bad.
•
Check parameter UE-68 and UE-69 should have a value of 1500 – 2000.
•
Check parameter UE-32 should have a value around 250 – 400.
•
Check parameter bA103 = 0.00 and bA101 = 00: Disabled.
•
Check parameter bA110 = 07: Keypad.
•
Contact Detroit Hoist for further assistance.
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