Hitachi SJ700-2 instruction manual Torque monitoring function, Forcing function FOC, Output torque

Related code

A044/A244: V/F characteristic curve selection, 1st/2nd motors

C001 to C008: Terminal [1] to [8] functions

Chapter 4 Explanation of Functions

Related code

A044/A244: V/F characteristic curve selection, 1st/2nd motors

C027: [FM] siginal selection

C028: [AM] siginal selection

C029: [AMI] siginal selection

H003/H203: Motor capacity, 1st/2nd motor

H004/H204: Motor poles setting, 1st/2nd motors

4.2.98 Torque monitoring function

The torque monitoring function allows you to monitor the estimated motor output torque when the V/F characteristic curve selection is the sensorless vector control, 0Hz-range sensorless vector control, or vector control with sensor. To monitor the output torque on the digital operator, select code "d012" on the digital operator.

To monitor the output torque as a signal output from the control circuit terminal block, see Section 4.2.77, "FM terminal," or 4.2.78, "AM and AMI terminals."

If the constant torque characteristic (VC), reduced-torque characteristic (1.7th power of VP), or free V/f characteristic is specified for the V/F characteristic curve selection (A044/A244), this function is disabled, and the display on the digital operator and the signal output from the control circuit terminal block are unpredictable.

The torque monitored by this function is displayed as a ratio to the torque the motor outputs when rotating in synchronization with the frequency corresponding to the motor's rated output. (The latter torque is 100%.)

Since this function estimates the output torque from the motor current, the accuracy of monitoring is about 20% when the inverter drives a motor that has the same output ratings as the inverter.

Item	Function code	Data or range of data	Description
V/F characteristic curve		03	Sensorless vector control
	A044/A244	04	0Hz-range sensorless vector control
selection		05	Vector control with sensor (not available
			for A244)
[FM] siginal selection	C027	02	Output torque
[AM] siginal selection	C028	11	Output torque (signed) (only for C028)
[AMI] siginal selection	C029
Motor capacity selection	H003/H203	0.20 to 75.0 (kW)
Motor pole selection	H004/H204	2, 4, 6, 8, or 10 (poles)

4.2.99 Forcing function (FOC)

The forcing function allows you to apply an exciting

current via an input terminal to the inverter to pre-build magnetic flux when "03" (sensorless vector control), "04" (0Hz-range sensorless vector control), or "05" (vector control with sensor) is specified for the V/F characteristic curve selection (A044/A244).

To use this function, assign function "55" (FOC) to an intelligent input terminal.

After the FOC function is assigned, the inverter will accept operation commands only when the FOC terminal is turned on.

If the FOC terminal is turned off while the inverter is operating the motor, the inverter sets the motor into the free-running state. If the FOC terminal is turned on subsequently, the inverter restarts the motor according to the setting of the restart mode after FRS (b088).

FOC

FW(RV)

Output frequency

The inverter does not operate the motor because the FOC terminal is off.

Free running	Restarting according to the
	setting of "b088"

Exciting current flows.

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