Toshiba VF-nC1 instruction manual How to determine the causes of other problems

E6581090

13.4How to determine the causes of other problems

The following table provides a listing of other problems, their possible causes and remedies.

	Problems	Causes and remedies
	The motor runs in	• Invert the phases of the output terminals U, V and W.
	the wrong direction.	• Invert the forward/reverse run-signal terminals of the external input
		device. (See 6.2 "Assignment of functions to control terminals".)
	The motor runs but	• The load is too heavy.
	its speed does not	Reduce the load.
	change normally.	• The soft stall function is activated.
		Disable the soft stall function. (See 5.10.)
		• The maximum frequency HJ and the upper limit frequency WN are set
		too low.
		Increase the maximum frequency HJ and the upper limit frequency
		WN.
		• The frequency setting signal is too low.
		Check the signal set value, circuit, cables, etc.
		• Check the setting characteristics (point 1 and point 2 settings) of the
		frequency setting signal parameters. (See 6.4.)
		• If the motor runs at a low speed, check to see that the stall prevention
		function is activated because the torque boost amount is too large.
		Adjust the torque boost amount (XD) and the acceleration time (CEE).
		(See 5.1.)
	The motor does not	• The acceleration time (CEE) or the deceleration time (FGE) is set too
	accelerate or	short.
	decelerate smoothly.	Increase the acceleration time (CEE) or the deceleration time (FGE).
	A too large current	• The load is too heavy.
	flows into the motor.	Reduce the load.
		• If the motor runs at a low speed, check whether the torque boost amount
		is too large. (See 5.9.)
	The motor runs at a	• The motor has an improper voltage rating.
	higher or lower	Use a motor with a proper voltage rating.
	speed than the	• The motor terminal voltage is too low.
	specified one.	Check the setting of the base frequency voltage parameter (H).
		(See 6.12.)
		Replace the cable with a cable larger in diameter.
		• The reduction gear ratio, etc., are not set properly.
13		Adjust the reduction gear ratio, etc.
		• The output frequency is not set correctly.
		Check the output frequency range.
		• Adjust the base frequency. (See 5.8.)
	The motor speed	• The load is too heavy or too light.
	fluctuates during	Reduce the load fluctuation.
	operation.	• The inverter or motor used does not have a rating large enough to drive
		the load.
		Use an inverter or motor with a rating large enough.
		• Check whether the frequency setting signal changes.
	Parameter settings	Change the setting of the parameter H (prohibition of change of
	cannot be changed.	parameter setting) to .. (permitted) if it is set at ...
		(prohibited).
		* For safety’s sake, some parameters cannot be set during operation.
		(See 4.1.4.)
	How to cope with parameter setting-related problems
	If you forget	You can search for all reset parameters and change their settings.
	parameters which
		* Refer to 4.1.3 for details.
	have been reset
	If you want to return	You can return all parameters which have been reset to their default
	all reset parameters
		settings.
	to their respective
		* Refer to 4.1.5 for details.
	default settings
		M-8