Equation 1:
Calculate the kinetic energy of the system. Any energy that is not lost to the system could be
regenerated to the DC bus.
E
M
= [1/2][J
M
+ J
L
]
ꞷ
2
M
; rotary motors
E
M
= [[1/2][M
M
+ M
L
]v
2
M
; linear motors
Where:
J
M
= rotor inertia (kg·m
2
)
J
L
= load inertia (kg·m
2
)
ꞷ
M
= motor speed before deceleration (rad/s)
M
M
= forcer mass (kg)
M
L
= load mass (kg)
v
M
= velocity (m/s)
Equation 2:
You will need a shunt resistor if the regenerated energy is greater than the Maximum Additional
Storage Energy that the internal bus capacitor can store (
).
E
Ca
= (1/2)· C · (V
2
M
- V
2
NOM
)
Where:
C
= bus capacitor (F) [4,800 µF or 1500 µF]
V
M
= turn on voltage for shunt circuit (V) [380 V or 865
V]
V
NOM
= nominal bus voltage (V) [320 V or 680 V, Typical]
Table 2-55:
Maximum Additional Storage Energy for a Standard iXC6e/XC6e
Bus Voltage
Maximum Additional Energy
320 V
100.8 J
680 V
214 J
If a shunt resistor is required, calculate the value of resistance necessary to dissipate the energy.
Equations 3
,
4
, and
5
:
Calculate the parameters of the shunt resistor.
Equation 3:
P
PEAK
= (E
M
- E
Ca
) / t
D
Where:
P
PEAK
= peak power the regeneration circuit must accommodate (W)
t
D
= deceleration time (s)
2.8. Shunt Options
iXC6e/XC6e Hardware Manual
76
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