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Sigma II User's Manual
5.6
Selecting a Regenerative Resistor
When the servomotor is driven 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 charging energy is exceeded, the regener-
ative power is further consumed by the regenerative resistor.
The servomotor is driven in regeneration (generator) mode in the following circum-
stances:
•
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 sufficient for short–
time operation only, such as for 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 specifications of the servo
amplifier's built–in resistor and the amount of regenerative power (average values) that it
can process.
Applicable Servo Amplifiers
100V
SGDH–A3BE to –02BE
SGDH–A3AE to –04AE
SGDH–05AE to –10AE
200V
SGDH–15AE
SGDH–20AE
SGDH–30AE
*
The amount of regenerative power (average value) that can be processed is rated at 20% of the capac-
ity 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 combining multiple small-capacity
regenerative resistors to increase the regenerative resistor capacity (W), select resistors so
that the resistance value including error is at least as high as the minimum allowable resis-
tance shown in the above table.
Chapter 5: Parameter Settings and Functions
Built-in Resistor
Specifications
Resistance
Capacity
(Ω)
(W)
—
—
—
—
50
60
30
70
25
140
12.5
140
5-82
Regenerative
Minimum
Power
Allowable
Processed
Resistance
by Built-in
(Ω)
Resistor* (W)
—
40
—
40
12
14
20
28
12
28
12
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