Mitsubishi Electric FR-D720-0.2K-G Instruction Manual page 114

(4) Pre-excitation (LX) signal
Turning ON the LX signal will apply excitation current during a stop to activate DC injection brake.
The deceleration-to-a-stop operation commanded by the LX signal decelerates the motor to 0r/min, then performs DC
injection brake operation, regardless of the Pr. 10 and Pr. 11 settings.
Performing the initial magnetic pole detection in advance will eliminate the start-up delay caused by the initial magnetic
pole detection. (Initial magnetic pole detection is performed when the LX signal is turned OFF and ON during a stop.)
To input the LX signal, set "23" in one of Pr. 178 to Pr. 182 (input terminal function selection) to assign the function to a
terminal.
The RY2 signal turns ON when the pre-excitation starts.
The signal stays ON as long as pre-excitation is activated even if the drive unit is in a stop status. The signal is OFF when
the output shutoff (MRS) signal is ON.
For the terminal used for the RY2 signal, set "33 (positive logic)" or "133 (negative logic)" in Pr. 190 or Pr. 192 (output
terminal function selection).
ON
STF
LX
(r/min)
Initial magnetic
pole detection
(approx. 100ms)
DC injection
brake
Operation time of Pr. 11
(When Pr. 11
RY2
ON
REMARKS
 RUN LED on the operation panel is lit during pre-excitation, which is activated by turning the LX signal ON.
NOTE
 Changing the terminal assignment using Pr. 178 to Pr. 182 (input terminal function selection) and Pr. 190 or Pr. 192 (output terminal
function selection) may affect the other functions. Set parameters after confirming the function of each terminal. (Refer to page
117.)
Install a mechanical brake to make an emergency stop or to stay stopped for a long time.
After the machine is completely stopped and the motor is immobilized using a mechanical brake, turn OFF the
pre-excitation (LX) signal.
A PM motor is a magnet motor. 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.
Parameters referred to
Pr. 13 Starting speed
Pr. 178 to Pr. 182 (input terminal function selection)
ON
Initial magnetic
pole detection
(approx. 100ms)
"0")
CAUTION
Refer to page 99.
Refer to page 117.
Motor brake and stop operation
ON ON
DC injection brake while the LX signal is ON.
ON
Time
Time
4
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