Digital Operator Display Fault Name
oL7
High Slip Braking oL
The output frequency stayed constant for longer than the time set in n3-04 during High Slip Braking.
Cause Possible Solution
Excessive load inertia
• Reduce deceleration times in parameters C1-02, C1-04, C1-06, and C1-08 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 the 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. Then reconnect the operator and turn the
drive input power back on.
Digital Operator Display Fault Name
oS
Overspeed (for Control Mode with PG)
The motor speed feedback exceeded the F1-08 setting.
Cause Possible Solution
Overshoot is occurring
• Increase the settings for C5-01 (Speed Control Proportional Gain 1) and reduce 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.
Refer to the Overvoltage Protection row in the A.3 Drive Specifications section on page 374 for trip level
values.
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 dynamic 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.
Excessive braking load
The braking torque was too high, causing regenerative energy to charge the DC bus. Reduce the braking
torque, use a dynamic braking option, or lengthen decel time.
Surge voltage entering from the drive input
power
Install a DC reactor.
Note: Voltage surge can result from a thyristor convertor and phase advancing capacitor using the
same input power supply.
Ground fault in the output circuit causes the
DC bus capacitor to overcharge
• Check the motor wiring for ground faults.
• Correct grounding shorts and turn the power back on.
6.4 Fault Detection
YASKAWA ELECTRIC SIEP C710616 31B YASKAWA AC Drive – A1000 Technical Manual
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6
Troubleshooting
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