Mitsubishi Electric A500 Inverter

The inverter output is stopped if a contact fault occurs at the connector between the inverter and a communication option, or if there is a fault of the communication option itself. The numbers 1 to 3 indicate the specific option slot numbers where the fault is detected.

This function stops the inverter output if a fault occurs in the brake circuit, typically due to damaged brake transistors. When this alarm appears, the inverter power must be switched off immediately to prevent further damage to the unit.

The inverter self-determines a CPU error and stops output if the arithmetic operation of the built-in CPU does not complete within a predetermined period. This typically indicates an internal processor malfunction or a severe software execution issue.

The inverter output is stopped if the encoder signal is lost or turned off. This typically occurs during orientation, PLG feedback, or vector control when executed with the FR-A5AP, indicating a break or interruption in the encoder signal wire.

This function stops the inverter output if the cooling fin overheats, causing the internal overheat sensor to actuate. This indicates that the inverter's heat dissipation is compromised, potentially due to environmental factors or cooling system issues.

This function stops the inverter output if a ground fault overcurrent flows due to a ground fault occurring in the inverter's output side (load side). This indicates an insulation breakdown in the motor or the cable connecting the inverter to the motor.

This protection activates if the main power supply (inverter input R, S, T or L1, L2, L3) experiences a power failure lasting longer than 15 milliseconds. It stops the inverter output to prevent control circuit malfunction. During the event, the alarm warning output contacts switch state (open across B-C, close across A-C). If the power failure duration exceeds 100 milliseconds, the alarm warning output is not provided, and the inverter may attempt to restart automatically if a start signal is present upon power restoration.

This function stops the inverter output if one of the three phases (U, V, W) on the inverter's output side (load side) results in an open phase. It can also activate if the rated motor current is extremely lower than the rated inverter current, suggesting a mismatch or very light loading conditions.

This error indication occurs if power is supplied only to the R1 and S1 <L11 and L21> terminals (control power) and a start signal is entered, without the main circuit power (R, S, T) <L1, L2, L3> being present. This indicates an incorrect power supply sequence or missing main power when attempting to operate the inverter.

If an external thermal relay (for motor overheat protection) or an internally mounted motor temperature relay switches on (contacts open), the inverter output is stopped. This function is activated only when the OH signal (value 7) is assigned to any of Pr. 180 to Pr. 186. The inverter requires a manual reset even if relay contacts automatically reset.

The running frequency has fallen to 0 due to the activation of stall prevention, indicated by 'OL' during operation. This signifies that the motor is operating under an overload condition, causing the inverter to reduce frequency to prevent an overcurrent shutdown.

This alarm stops the inverter output if a functional alarm occurs in the plug-in option loaded in the corresponding slot (1, 2, or 3). Examples include communication alarms for communication options or contact faults for other types of plug-in options.

This alarm stops the inverter output if two or more communication options are fitted (with exceptions for FR-A5NR). If a high power factor converter is connected, this alarm appears if an AC power supply is accidentally connected to the R, S, T <L1, L2, L3> terminals, which can result in inverter damage.

This function stops the inverter output if a fault occurs in the E2PROM device responsible for storing parameter settings. This issue might be related to an excessive number of write operations to the memory device, which can degrade its integrity.

This function stops the inverter output if communication between the inverter and the Parameter Unit (PU) is suspended due to disconnection or successive communication errors. This occurs when Pr. 75 is set to "2", "3", "16", or "17" for reset/disconnection detection, or if Pr. 121 is "9999" (RS-485) and the number of retries is exceeded, or if communication breaks for the time set in Pr. 122.

This function stops the inverter output if operation cannot be resumed properly within the set number of retries for a preceding alarm. This indicates that a recurring underlying issue prevented successful automatic recovery attempts.

The inverter's electronic overcurrent protection detects motor overheating due to sustained overload or reduced cooling during constant-speed operation. A pre-alarm (TH indication) activates at 85% of the preset overload value. The protective circuit then stops the inverter output when the specified overload value is reached. This internal protection may be insufficient for special motors (e.g., multi-pole motors, multiple motors) which require external thermal relays.

This protective function activates to prevent damage to the inverter's output transistors. It triggers when a current exceeding 150% of the inverter's rated output current flows for an extended duration, typically if immediate overcurrent protection (for currents >200%) does not activate. The protection utilizes inverse-time characteristics, with an overload immunity of 150% for 60 seconds, leading to an inverter output stop.

This function stops the inverter output if the power supply voltage reduces below 150V (for 200V class inverters) or approximately 300V (for 400V class inverters). This prevents decreased motor torque and increased heat generation in the control circuit. This function also activates if a jumper or DC reactor is not connected across terminals P/+-P1.

For inverters equipped with a cooling fan, this alarm appears on the operation panel when the cooling fan stops due to a fault or operates inconsistently with the setting of Pr. 244 "cooling fan operation selection". This indicates a problem with the inverter's active cooling system.

This is a warning indication for stall prevention due to overcurrent, not a hard stop. If the motor current exceeds 150% (factory default, adjustable) of the rated inverter current during acceleration, constant-speed operation, or deceleration, the inverter will adjust the frequency (stop increasing, lower, or stop decreasing respectively) to prevent an overcurrent shutdown. Frequency is restored once current drops below the threshold.