Yaskawa Z1000 AC Drive HVAC - Manual (Page 206)

Overload occurred when operating at low
speeds
• Reduce the load when operating at low speeds.
• Replace the drive with a model that is one frame size larger.
• Lower the carrier frequency (C6-02).
Excessive torque compensation Reduce the torque compensation gain in parameter C4-01 until there is no speed loss but less current.
Parameters related to Speed Search are set
incorrectly
• Check the settings for all Speed Search related parameters.
• Adjust the current used during Speed Search (b3-03) and the Speed Search deceleration time (b3-02).
• After Auto-Tuning, set b3-24 to 1 to enable Speed Estimation Speed Search.
Output current fluctuation due to input phase
loss
Check the power supply for phase loss.
Digital Operator Display Fault Name
oL3
Overtorque Detection 1
The current has exceeded the value set for torque detection (L6-02) for longer than the allowable time
(L6-03).
Cause Possible Solution
Parameter settings are not appropriate for the
load
Check L6-02 and L6-03 settings.
Fault on the machine side (e.g., machine is
locked up)
Check the status of the load. Remove the cause of the fault.
Digital Operator Display Fault Name
oL7
High Slip Braking oL
The output frequency stayed constant for longer than the time set to n3-04 during High Slip Braking.
Cause Possible Solution
Excessive load inertia
• Reduce deceleration times in parameters C1-02 and C1-04 for applications that do not use High Slip
Braking.
• Use a braking resistor to shorten deceleration time.
Motor is driven by the load
Something on the load side is restricting
deceleration
The overload time during High Slip Braking
is too short
• Increase parameter n3-04 (High-slip Braking Overload Time).
• Install a thermal relay and increase the setting of n3-04 to maximum value.
Digital Operator Display Fault Name
oPr
External Digital Operator Connection Fault
The external operator has been disconnected from the drive.
Note: An oPr fault will occur when all of the following conditions are true:
• Output is interrupted when the operator is disconnected (o2-06 = 1).
• The Run command is assigned to the operator (b1-02 = 0 and LOCAL has been selected).
Cause Possible Solution
External operator is not properly connected to
the drive
• Check the connection between the operator and the drive.
• Replace the cable if damaged.
• Turn off the drive input power and disconnect the operator. Reconnect the operator and reapply drive
input power.
Digital Operator Display Fault Name
ov
Overvoltage
Voltage in the DC bus has exceeded the overvoltage detection level.
• For 600 V class drives: approximately 1040 V
Cause Possible Solution
Deceleration time is too short and regenerative
energy is flowing from the motor into the drive
• Increase the deceleration time (C1-02 and C1-04).
• Install a dynamic braking resistor or a dynamic braking resistor unit.
• Set L3-04 to 1 to enable stall prevention during deceleration. Stall Prevention is enabled as the default
setting.
Fast acceleration time causes the motor to
overshoot the speed reference
• Check if sudden drive acceleration triggers an overvoltage alarm.
• Increase the acceleration time.
• Use longer S-curve acceleration and deceleration times.
• Enable the Overvoltage Suppression function (L3-11 = 1).
• Lengthen the S-curve at acceleration end.
5.4 Fault Detection
206 YASKAWA ELECTRIC TOEP YAIZ1U 03A YASKAWA AC Drive – Z1000 User Manual