Mitsubishi Electric F700 Instruction Manual page 117

Operation selection at power failure and
instantaneous power failure
When Pr. 162 = 0, 10 (with frequency search)
Instantaneous (power failure) time
Power supply
(R,S,T)
Motor
speed N (r/min)
Inverter
*
output frequency
f (Hz)
Inverter
output voltage
E (V)
Coasting Speed
+
time (Pr.57) detection time
* The output shut off timing differs according
to the load condition.
When Pr. 162 = 1, 11 (without frequency search)
Instantaneous (power failure) time
Power supply
(R,S,T)
Motor speed N
(r/min)
Inverter
*
output frequency
f (Hz)
Inverter
output voltage
E (V)
Coasting time
Pr. 57 setting
* The output shut off timing differs according
to the load condition.
(2) Restart coasting time (Pr. 57)
⋅ Coasting time is the time from when the motor speed is detected until automatic restart control is started.
⋅ Set Pr. 57 to "0" to perform automatic restart operation. The coasting time is automatically set to the value
below. Generally this setting will pose no problems.
00038 or less ......... 0.5s, 00052 to 00170...... 1s, 00250 to 01160 ......... 3.0s, 01800 or more .........5.0s
⋅ Operation may not be performed well depending on the load inertia moment (J) magnitude or operation
frequency. Adjust the coasting time between 0.1s and 5s according to the load specifications.
(3) Restart cushion time (Pr. 58)
⋅ Cushion time is the length of time taken to raise the voltage appropriate to the detected motor speed (output
frequency prior to instantaneous power failure when Pr. 162 = "1" or "11).
⋅ Normally the initial value need not be changed for operation, but adjust it according to the inertia moment (J) or
torque magnitude of the load.
110
(1) Automatic restart operation selection (Pr. 162)
Restart cushion
time (Pr. 58 setting)
Acceleration time
at a restart
(Pr. 611 setting)
Restart cushion
time
Pr. 58 setting
⋅ With frequency search
When "0 (initial value), 10" is set in Pr. 162, the inverter
smoothly starts after detecting the motor speed upon power
restoration.
⋅ During reverse rotation, the inverter can be restarted
smoothly as the direction of rotation is detected.
REMARKS
⋅ When the inverter capacity is two rank or more larger than
the motor capacity, the inverter may not start due to
overcurrent (OCT) alarm.
⋅ If two or more motors are connected to one inverter, the
inverter functions abnormally. (The inverter does not start
smoothly.)
⋅ Since the DC injection brake is operated instantaneously
when the speed is detected at a restart, the speed may
reduce if the inertia moment (J) of the load is small.
⋅ Without frequency search
When Pr. 162 = "1" or "11", automatic restart operation is
performed in a reduced voltage system, where the voltage
is gradually risen with the output frequency unchanged from
prior to an instantaneous power failure independently of the
coasting speed of the motor.
REMARKS
⋅ This system stores the output frequency prior to an
instantaneous power failure and increases the voltage.
Therefore, if the instantaneous power failure time exceeds
0.2s, the inverter starts at Pr. 13 Starting frequency (initial value
= 0.5Hz) since the stored output frequency cannot be
retained.
⋅ Restart operation at every start
When Pr. 162 = "10" or "11", automatic restart operation is
also performed every start, in addition to the automatic
restart after instantaneous power failure. When Pr. 162 = "0"
or "1", automatic restart operation is performed at the first
start after power supply-on, but the inverter starts at the
starting frequency at the second time or later.