Regenerative Power And Regenerative Resistance; Connecting External Regenerative Resistors - YASKAWA SGDH User Manual

6.5 Connecting Regenerative Resistors

6.5.1 Regenerative Power and Regenerative Resistance

The rotational energy of driven machine such as servomotor is returned to the SERVOPACK. This is called
regenerative power. The regenerative power is absorbed by charging the smoothing capacitor, but when the
power exceeds the capacitor's chargeable energy, the regenerative power is further consumed by the regenerative
resistor.
The servomotor is driven in regeneration state in the following circumstances:
• While decelerating to a stop during acceleration and deceleration operation.
• Continuous falling operation on the vertical axis.
• During continuous operation with the servomotor rotated from the load side (negative load).
The SERVOPACKs with a capacity of the single-phase 200 V with 30 to 400 W or 100 V with 30 to 200 W do
not have built-in regenerative resistors. If the operation exceeds the rotating speed specifications shown in the
4.5.3 Load Moment of Inertia, connect an external regenerative resistor.

6.5.2 Connecting External Regenerative Resistors

(1) Necessity of External Regenerative Resistors
SERVOPACK
Capacity
400 W or less
500 W to 5.0 kW
6.0 to 15.0 kW
Necessity of
External Regen-
erative Resistors
Not Required
No built-in regenerative resistor is provided, however, normally an external
regenerative resistor is not required.
Install external regenerative resistors when the smoothing capacitor in SER-
VOPACK cannot process all the regenerative power.
Not Required
A built-in regenerative resistor is provided as standard. Install external regen-
erative resistors when the built-in regenerative resistor cannot process all the
regenerative power.
Required
No built-in regenerative resistor is provided, so the external regenerative
resistor is required. If the external regenerative resistor is not connected with
the SERVOPACK, the alarm30 is detected as a regeneration error alarm.
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6.5 Connecting Regenerative Resistors
Explanation
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