Internal Shunt Option [-SI#]

The internal shunt option is used to limit the internal bus voltage caused by regeneration. Regeneration occurs during deceleration as mechanical energy is converted to electrical energy and stored in the internal power supply capacitors. Regeneration only occurs with PWM amplifier types (XSP3) and not linear amplifier types (XSL3).

The maximum amount of energy that the iXR3/XR3 can safely absorb depends on the line voltage and motor bus configuration as shown in Maximum Energy That The iXR3/XR3 Can Safely Absorb During Regeneration.

Table 2-3:     Maximum Energy That The iXR3/XR3 Can Safely Absorb During Regeneration

Bus Option	Input Voltage	Internal Capacitance	Energy (J)
VB7 - with split bus	125 VAC	8000 uF / 200 VDC	35
VB7 - without split bus	125 VAC	16000 uF / 200 VDC	70
VB8 - with split bus	240 VAC	2300 uF / 400 VDC	52
VB8 - without split bus	240 VAC	4600 uf / 400 VDC	104

To determine if the shunt option is required, use one of the equations that follow to calculate the stored mechanical energy. If the calculated value exceeds the value listed in Maximum Energy That The iXR3/XR3 Can Safely Absorb During Regeneration, the shunt option is required. For multiple axes, add the energy contribution for each axis that shares a power supply and decelerates simultaneously. Compare the sum against the maximum energy limits shown in Maximum Energy That The iXR3/XR3 Can Safely Absorb During Regeneration.

For Linear Axes:				For Rotary Axes:
	m	moving mass [kg]			J	inertia [kg·m 2 ]
	v	speed [m/s]			w	speed [rad/s]
	E	stored energy [J]			E	stored energy [J]