PGo - PG Disconnection (with Simple V/f and PG)
PG pulses were not received for a longer time than set in F1-14.
Possible Causes and Solutions:
+ Pulse input (RP) connection is disconnected. Reconnect the pulse input (RP).
+ Pulse input (RP) wiring is incorrect. Correct the wiring.
+ Motor brake is engaged. Ensure the motor brake is properly released.

rH - Overheating of Brake Resistor
Brake resistor protection was triggered.
Possible Causes and Solutions:
+ Deceleration time is too short, and excessive regenerative energy is flowing back to the drive. Check the load, deceleration time, and speed.
+ Excessive braking inertia. Recalculate the braking load and braking power.

rr - Dynamic Brake Transistor
The internal dynamic brake transistor is malfunctioning.
Possible Causes and Solutions:
+ Brake transistor is damaged. Power cycle the drive and check if the error recurs.

SEr - Too Many Speed Search Restarts
The number of speed search restarts exceeded the number set in b3-19.
Possible Causes and Solutions:
+ Speed Search parameters are set to incorrect values. Reduce the detection compensation gain during Speed Search.

STO - Motor Stall or Step Loss Detection
Motor stall or step loss occurred. The motor exceeded the stall torque.
Possible Causes and Solutions:
+ Incorrect motor code set (for Yaskawa motors). Enter the correct motor code for the used PM in E5-01.
+ The load is too heavy. Increase the value of n8-55 (Load Inertia for PM).

UL3 - Low Torque Detection 1
The current fell below the minimum value set for torque detection (L6-02) for longer than the allowed time (L6-03).
Possible Causes and Solutions:
+ Parameter settings are not suitable for the load type. Check the settings of L6-02 and L6-03 parameters.
+ There is a fault on the machine side. Check if there is any problem with the load.

UL4 - Low Torque Detection 2
The current fell below the minimum value set for torque detection (L6-05) for longer than the allowed time (L6-06).
Possible Causes and Solutions:
+ Parameter settings are not suitable for the load type. Check the settings of L6-05 and L6-06 parameters.
+ There is a fault on the machine side. Check if there is any problem with the load.

UL5 - Mechanical Weakness Detection 2
Operating conditions met the conditions set in L6-08.

Uv1 - DC Bus Low Voltage
One of the following conditions occurred when the drive stopped:
+ The voltage in the DC bus fell below the low voltage detection level (L2-05).
+ The fault is issued only when L2-01 = 0 or L2-01 = 1 and the DC bus voltage is lower than L2-05 for longer than L2-02.
Possible Causes and Solutions:
+ There is phase loss in the drive's input power. Check wiring errors in the main circuit of the drive's input power and correct the wiring.
+ One of the drive's input power wiring terminals is loose. Ensure there are no loose terminals and apply the torque specified in this guide to tighten the terminals.
+ There is an issue with the voltage coming from the drive's input power. Check the voltage and correct it according to the range listed in the drive's input power specifications.
+ There was a power outage. Correct the drive's input power.
+ Drive internal circuits are worn out. Check the maintenance time of capacitors (U4-05) and replace the drive if U4-05 exceeds 90%.
+ The drive's input power transformer is not large enough, and the voltage drops after power is turned on. Check the capacity of the drive's input power transformer.
+ The air inside the drive is too hot. Check the internal temperature of the drive.
+ There is an issue with the CHARGE indicator. Replace the drive.

Uv2 - Control Power Supply Voltage Error
The voltage for the control drive input power is too low.
Possible Causes and Solutions:
+ For drives of 7.5 kW or smaller, L2-02 was changed from the default value without Instantaneous Power Loss Transition. Correct the L2-02 parameter setting or install an optional Instantaneous Power Loss Transition unit.
+ Control power supply wiring is damaged. Power cycle the drive and check if the error recurs.

Uv3 - Low Voltage 3 (Current Limiting Circuit Error)
The current limiting circuit is malfunctioning.
Possible Causes and Solutions:
+ The contactor in the current limiting circuit is damaged. Power cycle the drive and check if the error recurs.

Diagnosing and Resetting Faults
When a fault occurs and the drive stops, follow the instructions below to eliminate the conditions that triggered the fault and then restart the drive.

u If a Fault Occurs Simultaneously with Power Loss

WARNING! Risk of Electric Shock. Before restarting the drive, ensure there is no short circuit between the main circuit terminals (R/L1, S/L2, and T/L3) or between ground and the main circuit terminals. Failure to comply can result in serious injury or death and damage to the equipment.

   Turn on the drive's input power.
   Use the U2-oo monitoring parameters to display data showing the drive's operating condition just before the fault occurred.
   Eliminate the cause of the fault and reset it.

Note: Check U2-02 (Fault History) to learn which faults were triggered. Information on the drive's condition when the fault occurred, such as frequency, current, and voltage, can be found between U2-03 and U2-17. Refer to the section on Displaying Fault Monitoring Data After a Fault on page 266 for information on how to display fault monitoring data.

Note: If the fault is still displayed after a power cycle, eliminate the cause of the fault and reset it.

+ Yaskawa V1000 Fault index 

+ V1000 User Manual

+ Yaskawa 2 Homepage 

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