Mitsubishi Electric 800 Series Instruction Manual page 604

• When the MC is installed on the inverter output side, set up so the MC is released after the magnetic flux decay operation
time (see below) has passed.
Motor capacity
(Pr.80 setting value)
Magnetic flux decay process time
NOTE
• When operating in anything other than the Real sensorless vector control, the inverter will immediately shutoff the output
when the X74 signal is turned ON.
• Even at the time of Real sensorless vector control, the inverter will immediately shutoff the output when the X74 signal is
turned ON during the automatic restart after instantaneous power failure and online auto tuning during the start up.
• When other output shutoff trigger (inverter fault, turning ON the MRS signal, etc.) occurs during the magnetic flux decay
operation, the magnetic flux operation is terminated, and the output is shut off immediately.
• Unlike the MRS signal, voltage is output during the magnetic flux decay output shutoff operation, so take caution on electric
shocks.
• When the release timing of the mechanical brake is too fast, the motor shaft may be rotated by dropping or external force.
When the release timing is too late, the overcurrent prevention operation or electronic thermal O/L relay may operate, so
perform release of the mechanical brake matching the equipment utilizing the output frequency detection (FU) signal and
output current detection (Y12) signal.
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other
functions. Set parameters after confirming the function of each terminal.
Braking operation selection for vector control (Pr.802, Pr.1299)
• Select the braking operation when the pre-excitation is performed with Pr.802 Pre-excitation selection from either zero
speed control or servo lock.
• Turning ON the RT signal enables the second pre-excitation selection (when Pr.450  "9999").
Pr.802 (Pr.1299) Pre-
setting excitation
0 Zero speed
(initial value) control
1 Servo lock
• The relation between the DC injection brake operation and pre-excitation operation is as follows.
Control method
V/F control
Advanced magnetic flux vector
control
Real sensorless vector control
Vector control
PM sensorless vector control
2.2 kW or lower 3.7 kW to 11 kW 15 kW to 30 kW 37 kW to 55 kW 75 kW or higher
250 ms 500 ms
It will try to maintain 0 r/min so the motor shaft will not rotate even when a load is applied. However,
it will not return to its original position when the shaft moves due to external force.
It will not perform position control, but operate only with the speed control.
It will try to maintain the position of the motor shaft even if a load is applied. When the shaft moves
due to external force, it will return to its original position after the external force is removed.
To perform the position control, this loop gain can be adjusted with Pr.422 Position control gain
(Pr.1298 Second position control gain).
Control Pr.802
Pr.850
mode (Pr.1299)
― ― ―
― ― ―
― 0
― 1
Speed
― 2
― 0
― 1
Torque
― 2
0 ―
Speed
1 ―
Torque ― ―
Position ― ―
Speed ― ―
800 ms 900 ms
Description
Deceleration stop LX-ON
DC injection brake ―
DC injection brake ―
DC injection brake
Zero speed
Zero speed
Magnetic flux decay
Zero speed
output shutoff
DC injection brake
Zero speed
Zero speed
Magnetic flux decay
Zero speed
output shutoff
Zero speed Zero speed
Servo lock Servo lock
Zero speed Zero speed
― Servo lock
DC injection brake ―
(G) Control parameters
1100 ms
X13-ON
(Pr.11 = "8888")
DC injection brake
DC injection brake
Zero speed
Zero speed
Zero speed
Zero speed
Zero speed
Servo lock
Zero speed
―
―
603
PARAMETERS
5
GROUP
G