6.4 Fault Detection
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual 285
Troubleshooting
6
The electrical thermal relay is operating at the wrong
level.
• Check the current rating listed on the motor nameplate.
• Check the value set for the motor rated current (E2-01).
Motor overheated by overexcitation operation.
• Overexcitation increases the motor losses and the motor temperature. If applied too long, motor damage can occur. Prevent
excessive overexcitation operation or apply proper cooling to the motor.
• Reduce the excitation deceleration gain (n3-13).
• Set L3-04 (Stall Prevention during Deceleration) to a value other than 4.
Speed Search related parameters are set incorrectly.
• Check values set to Speed Search related parameters.
• Adjust the Speed Search current and Speed Search deceleration times (b3-02 and b3-03 respectively).
• After Auto-Tuning, enable Speed Estimation Speed Search (b3-24 = 1).
Output current fluctuation due to input phase loss Check the power supply for phase loss.
Digital Operator Display Fault Name
oL2
Drive Overload
The thermal sensor of the drive triggered overload protection.
Cause Possible Solution
Load is too heavy. Reduce the load.
Acceleration or deceleration times are too short. Increase the settings for the acceleration and deceleration times (C1-01 through C1-08).
The output voltage is too high.
• Adjust the preset V/f pattern (E1-04 through E1-10). This will mainly involve reducing E1-08 and E1-10.
• Be careful not to lower E1-08 and E1-10 excessively because this reduces load tolerance at low speeds.
Drive capacity is too small. Replace the drive with a larger model.
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 (C4-01) until there is no speed loss but less current.
Speed Search related parameters are set incorrectly.
• Check the settings for all Speed Search related parameters.
• Adjust the current used during Speed Search and the Speed Search deceleration time (b3-03 and b3-02 respectively).
• After Auto-Tuning the drive, enable the Speed Estimation Speed Search (b3-24 = 1).
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 the settings of parameters L6-02 and L6-03.
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
oL4
Overtorque Detection 2
The current has exceeded the value set for Overtorque Detection 2 (L6-05) for longer than the allowable time (L6-06).
Cause Possible Solution
Parameter settings are not appropriate for the load. Check the settings of parameters L6-05 and L6-06.
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. Next reconnect the operator and turn the drive input power back on.
Digital Operator Display Fault Name
oS
Overspeed
The motor speed feedback exceeded the F1-08 setting.
Cause Possible Solution
Overshoot is occurring.
• Reduce the settings for C5-01 (Speed Control Proportional Gain 1) and increase C5-02 (Speed Control Integral Time 1).
• If using a Closed Loop Vector mode, enable Feed Forward and perform Inertia Auto-Tuning.
Incorrect speed feedback scaling if terminal RP is used
as speed feedback input in V/f control.
• Set H6-02 to the value of the speed feedback signal frequency when the motor runs at the maximum speed.
• Adjust the input signal using parameters H6-03 through H6-05.
Incorrect number of PG pulses has been set. • Check and correct parameter F1-01.
Inappropriate parameter settings. Check the setting for the overspeed detection level and the overspeed detection time (F1-08 and F1-09).
Digital Operator Display Fault Name
ov
Overvoltage
Voltage in the DC bus has exceeded the overvoltage detection level.
• For 200 V class: approximately 410 V
• For 400 V class: approximately 820 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, C1-04, C1-06, C1-08).
• Install a braking resistor or a dynamic braking resistor unit.
• Enable stall prevention during deceleration (L3-04 = 1).
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.
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