Toshiba VF-A7  ：Zero-speed stop mode selection, LED display  lights  lights

[Parameter setting]

Title	Function	Adjustment range	Default setting
	Motor shaft fixing control	: Disabled, : Enabled	

If the motor shaft fixing control parameter  is set at , DC braking continue at half a braking rate of that set with  to retain the motor after it has come to a full stop by DC braking. To terminate the motor shaft fixing control, cut off the standby signal (ST signal).

Output frequency [Hz]

Setting frequency



0

Output current [A]

0

Operating signal (F-CC)

Stand-by signal (ST-CC)

LED display  lights  lights

[s]



2

ON

OFF

ON

OFF

Note 1) Almost the same motor shaft fixing control can be exercised when DC injection braking is controlled by means of external signals.

Note 2) If the motor shaft fixing control parameter  is set at (enabled) when the output frequency is below the DC injection braking start frequency and terminals ST-CC are closed (ON), the DC injection braking function is activated and the motor shaft fixing control continues regardless of the setting of the D.C. braking time parameter .

However, when a general-purpose motor is operated, if the D.C. braking rate  is set above 60% and the D.C. braking time  is set at a certain value, the overload protective function may be activated by the electronic thermal protective function.

In addition, the inverter may automatically control the D.C. braking rate to avoid tripping. Note 3) If the motor shaft is set free because of a power failure, the brake shaft fixing control is

discontinued. Also, if the inverter trips when the motor shaft fixing function is active, the fixing control is discontinued, whether or not it automatically recovers from tripping by its retry function.

6.8.3 Zero-speed stop mode selection

 ：Zero-speed stop mode selection

・Function

This function controls motor in the zero-speed state at the time of a stop. If this function is set up, 0Hz reference will be put out instead of DC braking at the time of a stop, and a motor will be controlled in the setting time stop state. The monitor display serves as  during this control operation. This function operates only at the time of vector control (= , ) with a sensor.

Refer to the direct-current braking (6.8.1) for conditions of operation. The portion of DC injection braking is served as operation which set frequency reference to 0Hz.

[Parameter setting]

Title	Function	Adjustment range	Default setting
	Zero-speed stop mode selection	: Standard(DC injection braking)	
		: 0 Hz command
	DC injection braking start frequency	～ [Hz]	
	DC injection braking time	～ [s]	

Note.1) This function doesn't operate when = .

Note.2) If this function is set up, motor shaft fixing control()cannot be used. Note.3) This function doesn't operate at the time of a torque control and position control. Note.4) This function doesn't operate except the time of the vector control (= , ) with a

sensor. In order to use this function, the option board for PG feedback is required. In other than the vector control (= , ) with a sensor, the usual DC injection braking operates.

Note.5) Since the reference frequency that will suspend the motor abruptly from the state of high

F-17