Omron R88D-1SN ECT Series, User Manual, Page: 430 / 974

4 Configuration and Wiring
4 - 72 AC Servomotors/Servo Drives 1S-series with Built-in EtherCAT® Communications User’s Manual (I586)
4-4 Regenerative Energy Absorption
The Servo Drives have a built-in capacitor, which absorbs the regenerative energy produced during
motor deceleration, etc. When the built-in capacitor cannot absorb all regenerative energy, the Internal
Regeneration Resistor absorbs the rest of the energy. If the amount of regenerative energy from the
Servomotor is too large, regeneration operation stops and an Overvoltage Error occurs in order to pre-
vent the Internal Regeneration Resistor from burning.
If this occurs, reduce the regenerative energy by changing operating patterns, or increase the regener-
ation process capacity by connecting an External Regeneration Resistor.
Additional Information
• Some Servo Drive models do not have the Internal Regeneration Resistor.
• Regenerative energy absorption capacity depends on the Servo Drive model.
Refer to Amount of Internal Regeneration Absorption in Servo Drives on page 4-75 for
checking the Servo Drive model with Internal Regeneration Resistor and its regenerative
energy absorption capacity.
Regenerative energy calculation for a horizontal axis is explained.
• In the output torque graph, acceleration in the positive direction is shown as positive (+), and acceler-
ation in the negative direction is shown as negative (-).
• The regenerative energy values in each region can be calculated from the following equations.
Note Due to the loss from motor winding resistance and inverter, the actual regenerative energy will be approxi-
mately 90% of the values calculated from the above equations.
4-4-1 Calculating the Regenerative Energy
Motor operation
Motor output torque
+N1
- N2
TD1
TD2
t 1 t 2
T
Eg1 g1 Eg1
Eg2 g2 Eg2
N 1, N 2
: Rotation speed at start of deceleration [r/min]
: Deceleration torque [N·m]
: Deceleration time [s]
T D1, TD2
t1, t2