About The Dynamic Brake Hardware Option Specifications; What Is Dynamic Braking; Capabilities Of Servopacks That Support The Dynamic Brake Hardware Option Specifications - YASKAWA Sigma-7S Series Product Manual

1.1 About the Dynamic Brake Hardware Option Specifications

1.1.1 What Is Dynamic Braking?

1.1

About the Dynamic Brake Hardware Option Specifications

1.1.1

What Is Dynamic Braking?

If the servo turns OFF due to a loss of power or an emergency stop triggered by an alarm
during Servomotor operation, the SERVOPACK can no longer control the Servomotor. There-
fore, the Servomotor will continue to coast when the servo is turned OFF until all of the kinetic
energy from its speed and moment of inertia is expended. Only an extremely small amount of
kinetic energy is expended when the servo is turned OFF. This results in an extremely long
coasting distance, which can damage the machinery or cause personal injury.
Dynamic braking uses a coasting Servomotor as a power generator to brake the Servomotor.
The Servomotor's kinetic energy is converted to electrical energy and is expended as heat
through a resistor to stop the Servomotor.
1.1.2 Capabilities of SERVOPACKs That Support the Dynamic
Brake Hardware Option Specifications
A SERVOPACK that supports the dynamic brake hardware option specifications does not have
a built-in dynamic brake resistor, and you can achieve the following things with it by using an
external dynamic brake resistor or by not connecting a resistor at all.
Note: Standard SERVOPACKs include a built-in dynamic brake. However, because the dynamic brake is built in, the
brake torque is fixed and there is a limit to the amount of kinetic energy that can be processed by the Servo-
motor.
 Reduction of Brake Torque When Stopping with the Dynamic Brake
The brake torque can be adjusted according to the rigidity of the machine to prevent scattering
of conveyor objects caused by dynamic braking either by increasing the resistance of the
dynamic brake resistor or by not connecting the resistor at all.
 Application to Equipment or Machines with a Higher Load Moment of
Inertia Than the Allowable Load Moment of Inertia in the Standard
Specifications
The dynamic brake can be applied to a machine with a high load moment of inertia by increas-
ing the energy capacity of the dynamic brake resistor. If a dynamic brake resistor is not con-
nected, dynamic braking can be disabled to allow the Servomotor to be turned by the machine.
The following specification is different for different SERVOPACK models.
SERVOPACK Model
SGD7S-
SGD7W-
SGD7S-
SGD7W-
1-2
 Do not use the dynamic brake for any application other than an emergency stop.
There is a risk of failure due to rapid deterioration of elements in the SERVOPACK and the risk
of unexpected operation, machine damage, burning, or injury.
R70A to 2R8A,
R70F to 2R8F
1R6A to 2R8A
3R8A to 780A
5R5A to 7R6A
CAUTION
Specification
No dynamic brake
External dynamic brake resistor