Toshiba VF-A7 Indication Contents Expected causes Countermeasures, ･ Raise carrier frequency 

12.Prior to service call－Trip information and countermeasures

12.1 Cause of trip, warning indication (in detail and countermeasures)

If there is something abnormal in the inverter or system, troubleshoot referring to the following table before calling service. If the inverter needs to replace some part or the cause of the trouble cannot be removed by the measures mentioned in the table, consult the dealer of the inverter about the trouble.

[Trip information]

Indication	Contents	Expected causes			Countermeasures
		･ Acceleration time #1 is too short.	･ Extend acceleration time #1 .
		･ V/f parameter is improperly set.	･ Check V/f parameter.
	Overcurrent	･ Running motor is started during	･ Use (Auto-restart) or 
		momentary power failure.	(Regenerative power ride-through control).
	during
		･ Special motor (low impedance) is	･ Raise carrier frequency .
	acceleration
		used, isn't it?･
	(DC current)
		･ Manual torque boost value() is large.	･ Decrease setting value.
		･ Output cable or motor falls into	･ Check units and connections if there is
		ground-fault.	ground-fault or not.
	Overcurrent	･ Deceleration time #1  is too	･ Extend deceleration time #1 .
		short (in deceleration).
	during	･ Running motor is started during	･ Use  (Auto-restart) or  (Regen
	deceleration	momentary power failure.	erative power ride-through control).
	(DC current)	･ Output cable or motor falls into	･ Check units and connections if there is
		ground-fault.	ground-fault or not.
	Overcurrent	･ Load rapidly varied.	･ Reduce load variation.
	during	･ Load is abnormal.	･ Check loading unit.
	fixed speed	･ Output cable or motor falls into	･ Check units and connections if there is
	(DC current)	ground-fault.	ground-fault or not.
Note: ,,		･ A device of main circuit is faulty.	･ Make a service call.
 originate		･ Overheat protection is activated.	･ Check operation of cooling fan.
from causes other		(5.5 to 15 kW, 30 kW or more)	･ Check cooling fan control mode parameter
than those		･ Control voltage drop prevention function is	.
mentioned above.		activated. (5.5 to 15 kW, 30 kW or more)
	Overcurrent	･ Failure in wiring of main output	･ Check the wiring and motor insulation.
	(loaded side	circuit or motor insulation.	･ Properly set output short-circuit detection
	over-current at	･ Motor impedance is too low.	parameter and .
	start time)
	U-phase arm	･ Something abnormal in some	･ Make	a	service	call.
	short-circuit	device of main circuit (U-phase).
	V-phase arm	･ Something abnormal in some	･ Make	a	service	call.
	short-circuit	device of main circuit (V-phase).
	W-phase arm	･ Something abnormal in some	･ Make	a	service	call.
	short-circuit	device of main circuit (W-phase).
	Phase failure	･ Phase lacking in input side of	･ Check connection of main input circuit for
	(input side)	main circuit.	phase lacking in input side.
(*1)	Phase failure	･ Phase lacking in output side of	･ Check connection of main output circuit and
		main circuit.	motor for phase lacking in output side.
	(output side)		･ Select output phase failure detection parameter
			for checking.
		･ Input voltage abnormally varied.	･ Try to insert input reactor.
	Overvoltage	1: Power-factor improving capacitor was
		turned on/off.
	during	2: Some unit using thyrister is connected
	acceleration	with the same power supply line.
		･ Running motor is started during	･ Use (Auto-restart) and 
		momentary power failure status.	(Regenerative power ride-through control).
		･ Deceleration time #1 is too short	･ Extend deceleration time #1 .
		(too much regenerated energy).	･ Install dynamic braking resistor.
		･ PBR resistance is too high.	･ Decrease dynamic braking resistance.
		･ Dynamic braking mode is disabled.	(Also reset the .)
	Overvoltage	･ Over-voltage stall protection is	･ Set dynamic braking mode parameter 
	during	disabled.	properly.
	deceleration	･ Input voltage abnormally varied.	･ Set over-voltage stall protection 
		1 Power-factor improving capacitor was	properly.
		turned on/off.	･ Try to insert input reactor.
		2 Some unit using thyrister is connected
		with the same power supply line.

(*1): Presence or absence of parameter trip can be selected. (Continued on the following page)

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