OLR - Resistor Overload:

Excessive current at the Dynamic Braking Resistor.

    The deceleration time is too short.
    The DBR configuration is improperly set.

OP - Overvoltage:

The DC bus voltage exceeds the specified limits.

    The VFD is attempting to start a rotating motor after a temporary power loss.
    The incoming utility power is above the specified range.
    The deceleration time is too short.
    Voltage fluctuations at the 3-phase input; install an inductive filter.
    A DBR is required.
    The DBR resistance value is too high.
    The DBR function is turned off.
    Overvoltage Stall feature is disabled.
    The system is regenerating.
    Load instability.
    Disable the Ridethrough function (F302).

OT - Overtorque:

The torque requirement exceeds the settings of parameter F616 or F617 for a duration longer than that set by parameter F618.

    The VFD is not properly matched to the application.
    The setting of parameter F616 or F617 is too low.
    The load is obstructed.

POFF - Control Undervoltage:

A low voltage condition at the 5, 15, or 24 VDC supply.

    Defective Control board.
    Excessive load on the power supply.
    Low input voltage.

PtSt - Reference Point:

Two speed reference frequency setpoints are too close to each other.

    Increase the difference between the two speed reference frequency setpoints.

UC - Undercurrent:

The output current of the VFD is below the level defined by parameter F611 and remains there for the time set by parameter F612.

    Reset is ignored if active.

Alarms

Below are the alarm codes that may be displayed during the operation of the Q7 VFD, along with their descriptions and possible causes. If the source of the malfunction cannot be determined, contact your Toshiba Sales Representative for further information and appropriate solutions. Active alarms are displayed on the Frequency Command screen, and multiple active alarms are shown sequentially at one-second intervals.
Q7 VFD Alarm Codes and Descriptions

CM1 - Comm1 Error:

Internal communication error.

    Incorrectly programmed VFD.
    Incorrect communication settings.
    Improperly connected cables.

CM2 - Comm2 Error:

External communication error.

    Connection problems or faults in communication devices.

EMG - Emergency Off:

The output signal from the VFD is terminated, and a brake may be applied if configured.

    The Stop/Reset button was pressed twice on the keypad.
    An EOFF command was received remotely.
    The VFD needs to be reset.

MOFF - Main Undervoltage:

Low voltage condition at the 3-phase AC input to the VFD.

    Low 3-phase utility voltage.

OC - Overcurrent:

The output current of the VFD exceeds the setting of parameter F601.

    Faulty IGBT (U, V, or W).
    The VFD output is incorrectly connected to the motor. Disconnect the motor and retry.
    Phase-to-phase short at the VFD output.
    The VFD is starting into a rotating motor.
    Motor/machine is jammed.
    The mechanical brake is engaged while the VFD is starting or running.
    Acceleration/deceleration time is too short.
    Voltage Boost setting is too high.
    Load fluctuations.
    The VFD is operating at an elevated temperature.

OH - Overheat:

The ambient temperature of the VFD is excessively high.

    The VFD is operating at an elevated temperature.
    The VFD is too close to heat-generating equipment.
    The cooling fan vent is obstructed (see VFD Installation).
    The cooling fan is inoperative.
    The internal thermistor is disconnected.

OJ - Timer:

The runtime counter has exceeded its limit.

    A Type Reset is required; clear the run timer.

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