Omron 8U0108-E1-01, User Manual

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XtraDrive User Manual Chapter 5 : Parameter Settings and Functions
5-72
5.6. Selecting a Regenerative Resistor
When the servomotor operates in Generator mode, power is returned to the
servo amplifier side. This is called regenerative power. The regenerative
power is absorbed by charging the smoothing capacitor, but when the
capacitor’s charging limit is exceeded, the regenerative power is then reduced
by the regenerative resistor.
The servomotor is driven in regeneration (generator) mode in the following
conditions:
•
While decelerating to a stop during acceleration/deceleration
operation.
•
With a load on the vertical axis.
•
During continuous operation with the servomotor driven from the load
side (negative load).
The capacity of the servo amplifier’s built-in regenerative resistor is designed
for short-term operation only, such as the deceleration stop period. Operation
under a negative load is not possible.
If the regenerative power exceeds the processing capacity of the servo
amplifier, install an external regenerative resistor. The following table shows
the examples of specifications for servo amplifier’s built-in resistor and the
amount of regenerative power (average values) that it can process.
Built-in Resistor
Specifications
Applicable Servo Amplifiers
Resistance
( Ω )
Capacity
(W)
Regenerative
Power
Processed by
Built-in
Resistor* (W)
Minimum
Allowable
Resistance
( Ω )
XD-P3-** to –04-** — — —
Single-phase
200V
XD-08-** 50 60 12
40
Three-phase
400V
XD-20DE to -30DE 45 140 28 44
Note: The amount of regenerative power (average value) that can be processed is rated at 20% of the capacity of
the servo amplifier’s built-in regenerative resistor.
When installing an external regenerative resistor, make sure that the
resistance is the same as that of the servo amplifier’s built-in resistor. If you
combine multiple small-capacity regenerative resistors to increase the
regenerative resistor capacity (W), select the resistors in a way that the
resistance value including error is at least as high as the minimum allowable
resistance shown in the table above.