
B-65322EN/02 SVM 3.SPECIFICATIONS
- 15 -
3.6.2 When a Separated Regenerative Discharge Resistor Is
Needed
If the amount of energy regenerated per regeneration cycle exceeds
the maximum amount of energy that a servo amplifier can handle, a
DC link overvoltage alarm occurs. In this case, a separated
regenerative discharge resistor is needed.
Note in mind that an incorrect connection can damage the
amplifier.
Selecting a regenerative discharge resistor
First obtain how much regenerative energy occurs.
- For horizontal movement
Servo motor (for horizontal movement)
Amount of regenerative discharge (power [W]) when rapid traverse
acceleration/deceleration is performed once every F sec
(a) SI unit system
4)n (Expressio ][)1023.5)(1048.5(
1
1
2
23
WTLVmtaVmJLJm
F
w ⋅⋅⋅×−⋅+⋅××=
−
−
F : Frequency of rapid traverse acceleration/deceleration
[sec/number of times]
Unless otherwise specified, rapid traverse
acceleration/deceleration is assumed to be performed about
once every 5 seconds.
Jm: Rotor inertia of the motor [kg
⋅m
2
]
JL: Motor-shaft-converted inertia of the load [kg
⋅m
2
]
Vm: Motor speed at rapid traverse [min
-1
]
ta: Rapid traverse acceleration/deceleration time [sec]
TL: Machine frictional torque (motor-converted value) [N
⋅m]
(b) CGS unit system
4)n (Expressio ][)1013.5)(1037.5(
1
1
324
WTLVmtaVmJLJm
F
w ⋅⋅⋅×−⋅+⋅××=
−−
F : Frequency of rapid traverse acceleration/deceleration
[sec/number of times]
Unless otherwise specified, rapid traverse
acceleration/deceleration is assumed to be performed about
once every 5 seconds.
Jm: Rotor inertia of the motor [kgf
⋅cm⋅sec
2
]
JL: Motor-shaft-converted inertia of the load [kgf
⋅cm⋅sec
2
]
Vm: Motor speed at rapid traverse [min
-1
]
ta: Rapid traverse acceleration/deceleration time [sec]
TL: Machine frictional torque (motor-converted value) [kg
⋅cm]
From Table 3.6.2, select a separated regenerative discharge unit
having a greater regenerative discharge capacity than the value
obtained from (Expression 4).