Mitsubishi FR - S500 instruction manual Zero current detection

2.5.2 Zero current detection

When the inverter's	Start signal	OFF	ON
											Pr.50
output current falls to
											"zero
"0", torque will not be
	Output			Pr.50							current
generated. This may
							100ms				detection
	current 0 [A]
cause a gravity drop	Zero current			OFF		ON		OFF		ON	level"
when the inverter is	detection signal
					Pr.51				Pr.51
used in vertical lift	output (Y13)
					detection time				detection time

application.

To prevent this, the output current "zero" signal can be output from the inverter to close the mechanical brake when the output current has fallen to "zero".

Parameter	Name	Factory	Setting	Remarks
		Setting	Range
50	Zero current detection	5%	0 to 200%
	level			Setting is enabled when Pr. 30
51	Zero current detection	0.5s	0.05 to 1s	= "1"
	time

POINT

If the output is lower than the Pr.50 setting for longer than the time set in Pr. 51 during inverter operation, the zero current detection (Y13) signal is output from the inverter's open collector output terminal.

<Setting>

Parameter	Description
	Set the zero current detection level.

50Set the level of zero current detection in terms of the percentage of the rated inverter current from the output current value of 0 [A].

Set the zero current detection time.

51Set a period of time from when the output current falls to or below the Pr. 50 setting to when the zero current detection signal (Y13) is output.

CAUTION

•If the current falls below the preset detection level but the timing condition is not

•	satisfied, the zero current detection signal is held on for about 100ms.	2
	When the terminal functions are changed using Pr. 64, Pr. 65, the other functions
	may be affected. Confirm the functions of the corresponding terminals before
•	making settings.
	When one inverter is used to run (connect) multiple motors sequentially, the zero
	current detection signal (Y13) may be output. Set 13% or more for the 0.1K, and
	8% or more for the 0.2K. (If the sum of motor capacities is less than the zero

current detection level current or if the motor capacity per motor is less than the zero current detection level current)

♦ Related parameters♦

Assignment of Y13 signal to terminal ⇒ Pr. 64 "RUN terminal function selection", Pr. 65 "A, B, C terminal function selection" (refer to page90)

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