Regenerative Energy Absorption; Regenerative Energy Calculation - Omron R88M-W User Manual

System Design and Installation
3-3

Regenerative Energy Absorption

The Servo Drivers have internal regenerative energy absorption circuitry for absorbing
the regenerative energy produced during time such as Servomotor deceleration, and
thus preventing the DC voltage from increasing. An overcurrent error is generated, how-
ever, if the amount of regenerative energy from the Servomotor is too large. If this oc-
curs, measures must be taken to reduce the regenerative energy produced by changing
operating patterns, and so on, or to improve the regenerative energy absorption capac-
ity by connecting external regeneration resistance.

3-3-1 Regenerative Energy Calculation

H Horizontal Axis
Servomotor
operation
Servomotor
output torque
Note In the output torque graph, acceleration in the positive direction is shown as positive, and accel-
eration in the negative direction is shown as negative.
• The regenerative energy values for E
+ 1 @ 2p
E @ N
g1
2 60
+ 1 @ 2p
E @ N
g2
2 60
N , N : Rotation speed at beginning of deceleration [r/min]
1 2
T , T : Deceleration torque [NSm]
D1 D2
t , t : Deceleration time [s]
1 2
Note There is some loss due to winding resistance, so the actual regenerative energy will be approxi-
mately 90% of the values derived from these equations.
• For Servo Driver models with internal capacitors for absorbing regenerative energy (i.e., models of
400 W or less.), the values for both Eg1 or Eg2 (unit: J) must be lower than the Servo Driver's regen-
3-38
and E
g1
@ T @ t [J]
1 1
D1
@ T @ t [J]
2 2
D2
are derived from the following equations.
g2
Chapter 3