Motor Stopping Methods For Servo Off And Alarms - YASKAWA SGD7S Product Manual

5.13 Motor Stopping Methods for Servo OFF and Alarms

5.13

Motor Stopping Methods for Servo OFF and Alarms

You can use the following methods to stop the Servomotor when the servo is turned OFF or an
alarm occurs.
There are the following four stopping methods.
Motor Stopping Method
Stopping by Applying the
Dynamic Brake
Coasting to a Stop
Zero Clamping
Decelerating to a Stop
There are the following three conditions after stopping.
Status after Stopping
Dynamic Brake Applied
Coasting
Zero Clamping
Important
5-36
The electric circuits are internally connected to stop the Servomotor quickly.
The motor stops naturally due to friction during operation.
The speed reference is set to 0 to stop the Servomotor quickly.
Emergency stop torque is used to decelerate the motor to a stop.
The electric circuits are internally connected to hold the Servomotor.
The SERVOPACK does not control the Servomotor. (The machine will move in
response to a force from the load.)
A position loop is created and the Servomotor remains stopped at a position
reference of 0. (The current stop position is held.)
• The dynamic brake is used for emergency stops. The dynamic brake circuit will operate fre-
quently if the power supply is turned ON and OFF or the servo is turned ON and OFF while a
reference input is applied to start and stop the Servomotor. This may result in deterioration of
the internal elements in the SERVOPACK. Use speed input references or position references to
start and stop the Servomotor.
• If you turn OFF the main circuit power supply or control power supply during operation before
you turn OFF the servo, the Servomotor stopping method depends on the SERVOPACK model
as shown in the following table.
Condition
Main circuit power supply
turned OFF before turning
OFF the servo
Control power supply
turned OFF before turning
OFF the servo
• If the Servomotor must be stopped by coasting rather than with the dynamic brake when the
main circuit power supply or the control power supply is turned OFF before the servo is turned
OFF, use a Servomotor that has the dynamic brake option.
• To minimize the coasting distance of the Servomotor to come to a stop when an alarm occurs,
zero-speed stopping is the default method for alarms to which it is applicable. However,
depending on the application, stopping with the dynamic brake may be more suitable than
zero-speed stopping.
For example, when coupling two shafts (twin-drive operation), machine damage may occur if a
zero-speed stopping alarm occurs for one of the coupled shafts and the other shaft stops with
a dynamic brake. In such cases, change the stopping method to the dynamic brake.
Meaning
Meaning
Servomotor Stopping Method
SGD7S-R70A, -1R6A, -2R8A,
-3R8A, -5R5A, -7R6A, -120A,
-180A, -200A, -R70F, -R90F,
-2R1F, or -2R8F
Stopping with dynamic brake
Stopping with dynamic brake
SGD7S-330A, -470A, -550A,
-590A, or -780A
Coasting to a stop