Setting of operation voltage (torque) (Pr.12)
• Set the percentage against the power supply voltage in Pr.12 DC injection brake operation voltage. (The setting is not
used for zero speed control or servo lock.)
• The DC injection brake operation is not available when the setting of Pr.12 is 0%. (The motor will coast to stop.)
• When the setting of Pr.12 is the initial value, the setting corresponding to the motor is set according to the Pr.71 Applied motor
setting. (Refer to
as shown below.
FR-A820-00250(3.7K) or lower
FR-A840-00126(3.7K) or lower
FR-A820-00630(11K) to FR-A820-01250(22K), FR-A820-01870(37K) or higher
FR-A840-00310(11K) to FR-A840-00620(22K), FR-A840-00930(37K) or higher
• Even if the setting value of Pr.12 is made larger, braking torque will be limited so the output current will be within the rated
current of the inverter.
Braking operation selection under Real sensorless vector control (Pr.850
= "0 or 1")
• The braking operation under Real sensorless vector control can be selected between the DC injection brake operation
(initial setting) and zero speed control.
By setting Pr.850 Brake operation selection = "1", zero speed control will be performed at the frequency set in Pr.10 DC
injection brake operation frequency or lower.
• Under Real sensorless vector control, when the X13 signal turns ON while Pr.11 = "8888", zero speed control is activated
regardless of the Pr.850 setting.
• When restarting the operation after a brake operation under Real sensorless vector control, set Pr.850 = "1" (zero speed
control). Setting "0" (DC injection brake) may cause a delay of about 2 seconds from the time the start up command is input
until it actually is output.
Magnetic flux decay output shutoff and the Magnetic flux decay output
shutoff signal (X74 signal, Pr.850 = "2")
• Frequent starts/stops (inching) under Real sensorless vector control may cause an inverter failure or create a difference
in operation with the motor. The reason is that some magnetic flux is left in the motor at shutoff of the inverter output. If this
is the case, set Pr.850 = "2" (magnetic flux decay output shutoff) or turn ON the Magnetic flux decay output shutoff (X74)
signal to decay the magnetic flux at a stop, and then shut off the output.
• While Pr.850 = "2", deceleration starts at turning OFF of the start command, and the magnetic flux decay output shutoff is
activated when the estimated speed becomes lower than Pr.10 DC injection brake operation frequency.
• While the brake sequence function is active, the magnetic flux decay output shutoff is activated when the running frequency
drops to 0.5 Hz or Pr.13 Starting frequency, whichever is smaller.
508.) However, when an energy saving motor (SF-HR or SF-HRCA) is used, change the Pr.12 setting
5.16 (G) Control parameters