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4 System Design
OMNUC G5-series (Pulse-train Input Type) AC Servomotors and Servo Drives User’s Manual
4-4 Reg
en
erative En
er
gy Ab
sorp
tion
4
4-4-1 C
alculating
the Regene
rativ
e Energ
y
4-4
Regenerative Energy Absorption
The Servo Drives have internal regeneration process circuitry, which absorbs the regenerative energy
produced during motor deceleration and prevents the DC voltage from increasing. An overvoltage error
occurs, however, if the amount of regenerative energy from the motor is too large. If this occurs,
remedies must be taken to reduce the regenerative energy by changing operating patterns, or to
increase the regeneration process capacity by connecting an External Regeneration Unit.
• In the output torque graph, acceleration in the forward direction is shown as positive (+), and
acceleration in the reverse direction is shown as negative (–).
• The regenerative energy values in each region can be derived from the following equations.
Note Due to the loss of motor winding resistance and PWM, the actual regenerative energy will be
approximately 90% of the values derived from these equations.
• For Servo Drive models with internal capacitors used for absorbing regenerative energy (i.e., Servo Drive
models of 400 W or less), the values E
g1
and E
g2
(unit: J) must be lower than the drive’s regeneration
absorption capacity. (The capacity depends on the model. For details, refer to the next section.)
• For Servo Drive models with an Internal Regeneration Resistor used for absorbing regenerative
energy (i.e., Servo Drive models of 500 W or more), the average amount of regeneration Pr (unit: W)
must be calculated, and this value must be lower than the drive’s regeneration absorption capacity.
(The capacity depends on the model. For details, refer to the next section.)
The average regeneration power (Pr) is the regeneration power produced in 1 cycle of operation [W].
4-4-1
Calculating the Regenerative Energy
Horizontal Axis
Motor operation
Motor output
torque
+ N
1
– N
2
T
D1
T
D2
t
1
t
2
T
E
g1
E
g1
E
g2
E
g2
N
1
, N
2
: Rotation speed at start of deceleration [r/min]
: Deceleration torque [N•m]
: Deceleration time
T
D1
, T
D2
t
1
, t
2
2
E
g
1
E
g
=
P
r
(
+
) / T[W]
T : Operation cycle [s]
Summary of Contents for G5 R88D-KE Series
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