Mitsubishi Electric FR-F720P-0.75K to 110K Instruction Manual page 178

Instantaneous (power failure) time
Power supply
(R/L1,S/L2,T/L3)
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.
(4) 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" (without coasting time) to perform automatic restart operation.
Generally this setting will pose no problems.
Operation may not be performed well depending on the magnitude of the moment of inertia (J) of the load or running
frequency. Adjust the coasting time between 0.1s and 5s according to the load specifications.
(5) Automatic restart operation adjustment (Pr. 611)
Using Pr.611, the acceleration time to reach Pr.20 Acceleration/deceleration reference frequency can be set. This can be
set separately from the normal acceleration time.
REMARKS
Even if the Pr.21 Acceleration/deceleration time increments setting is changed, the setting increments of Pr. 611 remain unchanged.
CAUTION
An IPM motor is a motor with interior permanent magnets. Regression voltage is generated when the motor coasts at an
instantaneous power failure or makes a flying start. The inverter's DC bus voltage increases if the motor coasts fast or makes
a flying start in this condition.
When using the automatic restart after instantaneous power failure function (Pr. 57 Restart coasting time ≠ "9999"), it is
recommended to use the regenerative avoidance operation (Pr. 882 Regeneration avoidance operation selection = "1") in
combination for more a stable start. If the overvoltage protective function (E.OV ) activates at restart even with the
regeneration avoidance function, additionally use the retry function (Pr. 67).
An IPM motor is a motor with interior permanent magnets. High voltage is generated at motor terminals while the
motor is running. Do not touch motor terminals and other parts until the motor stops to prevent an electric shock.
When automatic restart after instantaneous power failure has been selected, the motor and machine will start
suddenly (after the reset time has elapsed) after occurrence of an instantaneous power failure.
Stay away from the motor and machine.
When you have selected the automatic restart after instantaneous power failure function, apply in easily visible
places the CAUTION stickers supplied.
♦ Parameters Referred to ♦
Pr. 13 Starting frequency Refer to page 113
Pr. 65, Pr. 67 to Pr. 69 Retry function
Pr. 78 Reverse rotation prevention selection
Pr. 178 to Pr. 189 (input terminal function selection)
Pr. 882 Regeneration avoidance operation selection
(3) Automatic restart operation selection (Pr. 162)
The inverter smoothly starts after detecting the motor speed
(frequency search) upon power restoration.
During reverse rotation, the inverter can be restarted
smoothly as the direction of rotation is detected.
REMARKS
Since the DC injection brake is operated instantaneously
when the speed is detected at a restart, the speed may
reduce if the moment of inertia (J) of the load is small.
Acceleration time
at a restart
(Pr. 611 setting)
Restart operation at every start
When Pr. 162 = "10 , (11)", automatic restart operation is also
performed every start, in addition to the automatic restart after
instantaneous power failure. When Pr. 162 = "0, (1)" automatic
restart operation is performed at the first start after power supply-
on, but starts at starting frequency at the second time or later.
REMARKS
Automatic restart operation with reduced voltage is not
available under IPM motor control. While Pr. 162 = "1 or 11,"
automatic restart operation is performed with a frequency
search (setting "0 or 10").
CAUTION
Refer to page 172
Refer to page 201
Refer to page 133
Refer to page 279
Operation selection at power failure
and instantaneous power failure
4
167