Chapter 12 Descriptions of Parameter SettingsMS300 
381 
 
07 Special Parameters                                       
 You can set this parameter during operation. 
Software Brake Chopper Action Level 
Default: 370.0 / 740.0 / 950.0 
115V / 230V models: 350.0–450.0 V
DC
                                                         
460V models: 700.0–900.0 V
DC
 
575V models: 875.0–1000.0 V
DC
 
 Sets the DC bus voltage at which the brake chopper is activated. Choose a suitable brake 
resistor to achieve the optimal deceleration performance. Refer to Chapter 7 Optional 
Accessories for information about brake resistors.
 Sets the level of the DC brake current output to the motor at start-up and stop. When setting the 
DC brake current, the rated current (Pr.00-01) is 100%. It is recommended that you start with a 
low DC brake current level and then increase until you reach the proper holding torque. 
However, the DC brake current cannot exceed the motor’s rated current to prevent the motor 
from burnout. Therefore, DO NOT use the DC brake for mechanical retention, otherwise injury or 
accident may occur.
DC Brake Time at Start-up 
 The motor may continue rotating due to external forces or the inertia of the motor itself. If you 
use the drive with the motor rotating, it may cause motor damage or trigger drive protection due 
to over-current. This parameter outputs DC current, generating torque to force the motor stop to 
get a stable start before motor operation. This parameter determines the duration of the DC 
brake current output to the motor when the drive starts up. Set this parameter to 0.0 to disable 
the DC brake at start-up.  
 The motor may continue rotating after the drive stops output due to external forces or the inertia 
of the motor itself. This parameter outputs DC current, generating torque to force the motor stop 
after the drive stops output to make sure that the motor stops. 
 This parameter determines the duration of the DC Brake current output to the motor when 
braking. To enable the DC brake at STOP, you must set Pr.00-22 (Stop Method) to 0 (ramp to 
stop). Set this parameter to 0.0 to disable the DC brake at stop. 
 Related parameters:   
  Pr.00-22 Stop Method 
  Pr.07-04 DC Brake Frequency at STOP.