Xenus Plus User Guide 16-01344 Rev 06
Copley Controls 62
2.13.2: XE2/XP2/XM2/800-1819
Regeneration
The Xenus Plus Dual Axis drives, excluding the 800-1818, 800-1887 and “-N” models, have an
internal regen resistor which can dissipate regenerative energy that exceeds the absorption capacity
of the internal bus capacitance. The internal regen resistor will be switched on when the energy
shown in the table has been absorbed and the bus voltage driven up to 390 Vdc at which point the
internal regen resistor will be switched to dissipate the kinetic energy of the load.
Step 1: Find the energy of motion for a rotating load, for this
example let it be 75 Joules:
E = J * RPM
2
/ 182
= 75 J
Step 2: Subtract the absorption at your mains voltage to get the
energy that must be dissipated in the regen resistor during
the Regen Time.
Use 240 Vac:
75J - 43J = 32 J
Step 3: Divide the regen energy by the continuous power rating
of 20 Watts to get the dwell time that can dissipate the
regen energy in the resistor:
Dwell Time = 32 Joules / 20 Watts = 1.6 sec
Step 4: Find the total regen cycle time by adding the deceleration
time to the dwell time:
Regen Time = 1.25 sec
Dwell Time = 1.60 sec
Cycle Time = 2.85 sec
Internal Regen Resistor Ratings
Absorption is the energy that can be transferred to the internal capacitors during
deceleration. This table shows the energy absorption in W·s for a drive operating at
some typical mains voltages. The capacitor bank is 2350 uF and the energy
absorption is shared with both axes. If the deceleration energy is less than the
absorption capacity of the drive, then a regeneration resistor will not be used
because the bus voltage will not rise enough to hit the over-voltage level that would
disable the PWM outputs.
E Energy Joules, Watt·seconds
J Rotary Moment of Inertia kg·m
2
P Power Watts
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