Parker Aries AR-04CE - Energy Absorbed by Drive Capacitors; Table 39 Drive Capacitor Absorption

Parker Hannifin
- 90 – Aries Controller Hardware Installation Guide
calculate the potential energy that must be absorbed or dissipated
elsewhere.
mghEp
=
Where
E
p
= potential energy (Joules)
m = mass of forcer and load (kg)
g = gravitational constant (9.81 m/s
2
)
h = vertical height change during deceleration (m)
Energy Absorbed by Drive Capacitors
The Aries Controller drive capacitors absorb some of the kinetic and potential
energy. While the capacitors absorb energy, the bus voltage increases.
Later, the capacitors release that potential energy in subsequent
accelerations, or into typical drive losses.
If too much energy is absorbed by the capacitors, the drive/controller faults
from over-voltage. Under these circumstances, an external power dump
resistor is required.
That ability to absorb energy can be defined in terms of capacitance and
voltage.
)(
2
1
22
NOMTRIPC
VVCE −=
Where
E
C
= energy that can be absorbed by the drive capacitors (Joules)
C = drive capacitance (Farads)
V
TRIP
= power dump trip DC voltage (400 VDC)
V
NOM
= nominal DC motor voltage (typically AC mains voltage at
2
; for
example, 120 VAC *
2
= 170 VDC)
Fortunately, for a given drive/controller, the capacitance and voltages are
fixed. Table 39 provides the necessary informatio
n and results from the
above calculation.
Drive/
Controller
Capacitan
ce (uF)
V
TRIP
(VDC)
E
C
(120
VAC)
Joules
E
C
(240 VAC)
Joules
AR-04CE 880 400 57 19
AR-08CE 1100 400 72 24
AR-13CE 1590 400 104 35
When the voltage drops below 385 VDC, the drive stops dissipating power through the power
dump resistor.
Table 39 Drive Capacitor Absorption