Mitsubishi Electric 800 Series Instruction Manual page 27

 Upper limit fault detection
Operation panel
indication
The inverter output is shut off when the load exceeds the upper limit fault detection range. This protective function
Description
is not available in the initial setting of Pr.1490 (Pr.1490 = "9999").
• Check if too much load is applied to the equipment.
Check point
• Check that the load characteristics settings are correct.
• Inspect the equipment.
Corrective action
• Set the load characteristics (Pr.1481 to Pr.1487) correctly.
Reference FR-E800 Instruction Manual (Function)
 Lower limit fault detection
Operation panel
indication
The inverter output is shut off when the load falls below the lower limit fault detection range. This protective
Description
function is not available in the initial setting of Pr.1491 (Pr.1491 = "9999").
• Check if the equipment load is too light.
Check point
• Check that the load characteristics settings are correct.
• Inspect the equipment.
Corrective action
• Set the load characteristics (Pr.1481 to Pr.1487) correctly.
Reference FR-E800 Instruction Manual (Function)
 Brake transistor alarm detection
Operation panel
indication
• The inverter output is shut off if a fault due to damage of the brake transistor and such occurs in the brake
Description circuit.
In such a case, the power supply to the inverter must be shut off immediately.
• Reduce the load inertia.
Check point
• Check that the brake duty is proper.
Corrective action Replace the inverter.
 Output side earth (ground) fault overcurrent
Operation panel
indication
The inverter output is shut off if an earth (ground) fault overcurrent flows due to an earth (ground) fault that
Description
occurred on the inverter's output side (load side).
Check point Check for a ground fault in the motor and connection cable.
Corrective action Remedy the earth (ground) fault portion.
Reference FR-E800 Instruction Manual (Function)
 Output phase loss
Operation panel
indication
Description The inverter output is shut off if one of the three phases (U, V, W) on the inverter's output side (load side) is lost.
• Check the wiring. (Check that the motor is normally operating.)
Check point • Check that the capacity of the motor used is not smaller than that of the inverter.
• Check if a start command is given to the inverter while the motor is coasting. (PM sensorless vector control)
• Wire the cables properly.
Corrective action • Input a start command after the motor stops. Alternatively, use the automatic restart after instantaneous power
failure / flying start function. (PM sensorless vector control)
Reference FR-E800 Instruction Manual (Function)
 External thermal relay operation
Operation panel
indication
The inverter output is shut off if the external thermal relay provided for motor overheat protection or the internally
mounted thermal relay in the motor, etc. switches ON (contacts open). This function is available when "7" (OH
Description
signal) is set in any of Pr.178 to Pr.184 (Input terminal function selection). This protective function is not
available in the initial status. (OH signal is not assigned.)
• Check for motor overheating.
Check point • Check that the value "7" (OH signal) is set correctly to any of Pr.178 to Pr.184 (Input terminal function
selection).
• Reduce the load and operation duty.
Corrective action
• Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.
E.LUP
E.LDN
E.BE
E.GF
E.LF
E.OHT
2. Protective Functions
2.5 Causes and corrective actions
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