Toshiba VF-s15 fault codes
Toshiba VF-S15 Fault Codes and Troubleshooting
If a Toshiba VF-S15 trips because of a fault, do not simply reset the drive and start the machine again. First find and remove the cause of the trip. If the original problem is still present, the inverter will normally trip again and repeated resets may create additional problems for the motor or machine.
How to reset the VF-S15 after a trip
The VF-S15 can be reset in several ways. If you reset it by switching off the power, leave the drive off until the LED display has completely gone out. The way trip information is retained after power-off is related to the F802 – Trip record retention setting.
For an external reset, the RES function must be assigned to one of the digital input terminals. The reset command is applied through the assigned RES terminal and CC or P24. Reset input function numbers are 8 and 9.
The drive can also be reset from the operation panel or by sending a trip-clear command through communication.
Resetting from the keypad: Press the STOP key while the trip is displayed. When cLr appears, press STOP again. If the cause of the trip has already been removed, the drive will reset.
Some overload trips cannot be reset immediately. The VF-S15 uses a virtual cooling period before allowing a reset.
OL1 – Inverter overload: approximately 30 seconds.
OL2 – Motor overload: approximately 120 seconds.
OLr – Braking resistor overload: approximately 20 seconds.
OL3 – Main module overload does not use a virtual cooling period.
For an OH – Overheat trip, the drive checks its internal temperature. Allow the inverter to cool before trying to reset it. Check cabinet temperature, airflow, cooling conditions and motor load if the fault returns.
The drive cannot be reset while an emergency-stop signal is active or while a condition that prevents resetting is still present.
Caution: Turning the power off and back on can reset the inverter quickly, but it should not be used as a normal troubleshooting method. Repeated power cycling without correcting the cause of the fault may damage the drive, motor or connected machine.
Motor Does Not Run, but No Trip Code Is Displayed
If the VF-S15 shows no trip but the motor does not run, first check two basic things: Is the drive receiving a RUN command, and is the frequency reference above zero?
If the display is completely off: Check the incoming power supply, fuses and MCCB. If the correct supply voltage is present but the display remains off, there may be a problem in the drive power circuit.
Also check the connection between P0 and PA where the model or installation requires the factory shorting bar.
If OFF is displayed: Check the standby condition. Make sure the terminal assigned to ST – Standby is in the correct state and that any terminal assigned to the F/RR – Coast stop function is not preventing operation.
Also check F110 – Always active function selection. An incorrect setting here can leave the drive in standby even though no actual fault is present.
If a fault message is displayed: Find and correct the cause before resetting the drive. Clearing the code without fixing the problem is not a repair.
If rtry and a fault code are displayed alternately: The VF-S15 is in the automatic retry process. The retry sequence can be stopped by a normal stop, emergency stop or by switching off the inverter as appropriate for the machine.
If the RUN/STOP LED is on but the motor does not turn: If panel control is selected, press the RUN key and make sure the panel frequency reference is not zero. If the run command is expected from another source, check the CMOd – Command mode selection setting.
If the RUN/STOP LED is off: Check whether the external RUN command is actually reaching the inverter. Also check the input-terminal assignments and the SW1 SINK / PLC / SOURCE logic setting.
If 0.0 is displayed: Check whether the frequency reference is set to zero. Confirm the FMOd – Frequency setting mode, analog input scaling, preset-speed values and minimum/start frequency settings.
Also make sure the motor is not mechanically locked and that the load is not too heavy for the motor to start.
The VF-S15 monitor screens can show the actual state of the input terminals. This is very useful for finding out whether a problem is caused by wiring, a terminal assignment or a parameter setting.
If the reason is still not obvious, use the drive's parameter display and status-monitor functions. RUN command status, frequency reference, terminal states, output frequency and motor current usually provide useful clues.
Motor Runs in the Wrong Direction
If the motor turns in the wrong direction, swap any two motor phases at U/T1, V/T2 and W/T3. If forward/reverse control is coming from external terminals, check the FWD and REV commands as well.
If direction is selected from the operation panel or parameters, check the related forward/reverse setting before changing the motor wiring.
Motor Runs, but the Speed Does Not Change Normally
First check whether the mechanical load is too heavy for the motor or drive. If stall prevention becomes active, the VF-S15 may intentionally limit the output frequency to protect the system.
Check FH – Maximum frequency and UL – Upper limit frequency. If either value is set too low, the motor cannot reach the required speed.
Also check the external speed-reference signal, analog input level, potentiometer and associated wiring.
If the motor struggles at low speed, check the torque boost setting. Too much boost can increase motor current and cause current limiting or stall prevention to operate. Adjust the torque boost and ACC – Acceleration time if necessary.
Motor Does Not Accelerate or Decelerate Smoothly
The acceleration or deceleration time may be too short for the machine. Increase ACC or DEC if the drive reaches its current or voltage limit during speed changes.
On high-inertia machines, an excessively short deceleration time can raise the DC bus voltage and cause an overvoltage trip.
Motor Current Is Too High
Check whether the mechanical load is excessive. A torque-boost setting that is too high can also increase motor current, especially at low speed.
Make sure the motor rated current and other motor data entered in the VF-S15 match the actual motor nameplate.
Motor Runs Faster or Slower Than Expected
Check the motor rated voltage, drive output frequency and the machine's mechanical transmission ratio.
If the voltage at the motor terminals is lower than expected, check the VLV – Base frequency voltage setting and voltage drop in the motor cable.
A long or undersized motor cable can produce additional voltage drop. Use a suitable cable size for the motor current and installation length.
If the machine uses a gearbox, also check the gear reduction ratio, motor pole count and commanded output frequency.
Motor Speed Fluctuates During Operation
First check whether the mechanical load itself is changing. A rapidly changing load can naturally cause speed variation.
Check that the motor and inverter are large enough for the application. An undersized motor or drive may not maintain stable speed under changing load.
If the frequency reference comes from an analog signal or communication network, monitor the actual reference value. Noise or an unstable external reference will also cause motor speed to change.
If vector control is being used, check the motor data and auto-tuning settings as well.
VF-S15 Parameters Cannot Be Changed
Check F700 – Parameter setting selection. If parameter editing is locked, change the setting as required by the application. With the normal unlocked setting, F700 = 0.
If password protection is active, the password configured through F738 must be verified through F739 before protected settings can be changed.
Digital input functions can also lock parameter access. If an input has been assigned one of the 200–203 parameter read/write lock functions, parameter editing may be blocked while that input is active.
Some parameters cannot be changed while the motor is running. Stop the machine normally and try the setting again.
VF-S15 Communication Does Not Work
For RS485 or Modbus problems, check the drive address, baud rate, parity, communication wiring and termination settings.
If communication is being used for the frequency command or RUN command, also make sure the CMOd and FMOd settings are selecting the intended command sources.
For detailed network troubleshooting, use the relevant VF-S15 communication manual for RS485, Modbus, CANopen, DeviceNet, EtherCAT, PROFIBUS or the installed communication option.
If You No Longer Remember Which Parameters Were Changed
The VF-S15 includes parameter-search functions that can help identify settings that differ from the standard values. This is usually safer than immediately restoring the entire drive to factory defaults.
If a factory reset is necessary, first record the motor data, terminal assignments, communication settings and machine-specific parameters. Otherwise the drive may no longer operate correctly with the machine after the reset.
Toshiba VF-S15 – User Manuals and Fault Codes
VF-S15 main page | VF-S15 user manuals | Fault codes and troubleshooting | Fault code index
Fault Codes 1: Overcurrent, phase loss and overvoltage
Fault Codes 2: Drive overload, motor overload, torque and overheating
Fault Codes 3: Emergency stop, memory, communication and auto-tuning faults
Fault Codes 4: Ground fault, synchronization loss, overspeed and hardware faults
Fault Codes 5: PM motor auto-tuning, status messages and warnings
* The information on this page is intended to help with troubleshooting. Before making electrical measurements, changing wiring or carrying out physical work on the drive, always follow the original Toshiba VF-S15 documentation and the safety procedures for the machine.