6.4 Fault Detection
YASKAWA ELECTRIC
SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual
253
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LED Operator Display
Fault Name
PF
Input Phase Loss
Drive input power has an open phase or has a large imbalance of voltage between phases. Detected
when L8-05 = 1 (enabled).
Cause
Possible Solution
There is phase loss in the drive input power.
• Check for wiring errors in the main circuit drive input power.
• Correct the wiring.
There is loose wiring in the drive input
power terminals.
• Ensure the terminals are tightened properly.
• Apply the tightening torque specified in this manual to fasten the terminals.
and Tightening Torque on page 53
There is excessive fluctuation in the drive
input power voltage.
• Check the voltage from the drive input power.
• Review the possible solutions for stabilizing the drive input power.
• Disable Input Phase Loss Detection (L8-05 = “0”). PF is detected if DC bus ripple is too high. If it
is disabled, there is no fault but the ripple is still too high, thereby the capacitors are stressed more
and lose lifetime.
There is poor balance between voltage
phases.
• Stabilize drive input power or disable phase loss detection.
The main circuit capacitors are worn.
• Check the maintenance time for the capacitors (U4-05).
• Replace the drive if U4-05 is greater than 90%.
• Check for anything wrong with the drive input power.
• If nothing is wrong with the drive input power, try the following solutions if the alarm continues:
• Disable Input Phase Loss Protection selection (L8-05 = “0”). PF is detected if DC bus ripple is too
high. If it is disabled, there is no fault but the ripple is still too high, thereby the capacitors are
stressed more and lose lifetime.
• Replace the drive.
LED Operator Display
Fault Name
PGo
PG Disconnect (for Simple V/f with PG)
No PG pulses are received for longer than the time set to F1-14.
Cause
Possible Solution
Pulse input (RP) is disconnected.
Reconnect the pulse input (RP).
Pulse input (RP) wiring is wrong.
Correct the wiring.
Motor brake engaged.
Ensure the motor brake releases properly.
LED Operator Display
Fault Name
rH
Braking Resistor Overheat
Braking resistor protection was triggered.
Fault detection is enabled when L8-01 = 1 (disabled as a default).
Cause
Possible Solution
Deceleration time is too short and excessive
regenerative energy is flowing back into the
drive.
• Check the load, deceleration time and speed.
• Reduce the load.
• Increase the acceleration and deceleration times (C1-01 through C1-08).
• Replace the braking option with a larger device that can handle the power that is discharged.
Excessive braking inertia.
Recalculate braking load and braking power. Then try reducing the braking load and checking the
braking resistor settings and improve braking capacity.
The proper braking resistor has not been
installed.
• Check the specifications and conditions for the braking resistor device.
• Select the optimal braking resistor.
Note:
The magnitude of the braking load trips the braking resistor overheat alarm, NOT the surface temperature. Using the braking resistor more
frequently than its rating trips the alarm even when the braking resistor surface is not very hot.
LED Operator Display
Fault Name
rr
Dynamic Braking Transistor
The built-in dynamic braking transistor failed.
Cause
Possible Solution
The braking transistor is damaged.
• Cycle power to the drive and check if the fault reoccurs.
Refer to Diagnosing and Resetting Faults
.
• Replace the drive if the fault continues.
The control circuit is damaged.
