Hitachi SJ700-2 instruction manual Power supply Inverter output Motor speed

Chapter 4 Explanation of Functions

*1 If the inverter trips because of overvoltage or overcurrent while decelerating the motor, the inverter will display error code "E16" (instantaneous power failure), and the motor will start free-running. If this error occurs, prolong the deceleration time.

*2 If a DC voltage (P-N) is supplied to control power supply terminals R0 and T0, the inverter may detect undervoltage and trip when the inverter power is turned off. If this cause a problem in your system, specify "00" or "02" for the trip selection.

*3 The inverter may start the motor with 0 Hz if:

1)the output frequency is not more than half the base frequency or

2)the voltage induced on the motor is attenuated quickly.

*4 Even when a retry operation (01 to 03)is specified for the selection of restart mode (b001) and "disabling tripping" (00 or 02) is specified for the selection of a trip after instantaneous power failure or undervoltage in the stopped state, the inverter will trip if the instantaneous power failure continues over the allowable under-voltage power failure time. (See example 2.)

*5 Even when a retry operation is specified for the trip selection, the inverter will trip if the cause of trip is not removed by the end of the retry wait time before motor restart (b003). If this occurs, prolong the retry wait time.

*6 Even when a retry operation is specified for the retry selection, the inverter will trip if the undervoltage status continues for 40 seconds or more.

*7 when starting the motor with matching frequency is selected, inverter may restart suddenly by alarm resetting, resetting and retry-start.

The figures below show the timing charts for starting with a matching frequency (when "02" is specified for the selection of restart mode [b001]).

t0: Duration of instantaneous power failure

t1: Allowable under-voltage power failure time (b002)

t2: Retry wait time before motor restart (b003)

(Example 1)

Power supply

Inverter output

Motor speed

				(Example 2)
				Power supply
				Inverter output
		Free	-running			Free-running
				Motor speed
t0		t2			t0
	t1				t1

(Example 3) When the motor frequency (speed) is more than the setting of "b007":

(Example 4) When the motor frequency (speed) is less than the setting of "b007":

Power supply

Inverter output

Motor frequency (speed)

0

				Power supply
				Inverter output
		Free-	running			Free-running
			b007	Motor frequency			b007
				(speed)
			Starting with	0
			matching
t0	t2		frequency		t0	t2	Starting with
							0 Hz

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