SAF OPAL Pro MS6 - Manual (Page 23)

MS6 REDUCED VOLTAGE STARTER
Page 22
7.7 DC INJECTION BRAKING
• DC injection braking provides smooth braking for AC induction motors.
• DC injection offers adjustable braking because it is current controlled.
• Unlike a mechanical brake, an electrical brake will never wear out.
• The brake operates by injecting DC current in two phases of the motor to rapidly decelerate
it to zero speed.
• When stop is commanded the Opal Pro shuts off for 2 seconds to allow the voltage across
the motor to drop. The DC injection current is then applied at a level set in parameter 1104
for the amount of time set in parameter 1105. It does not provide zero speed sensing,
although if two wire control is used terminal 4 can be used to disable the DC injection
(activated = enabled).
• If braking is released before the motor stops, the motor will coast to rest. If the braking
remains on after the motor stops, the DC supply will provide a holding brake.