Parker Aries AR-08AE - Resistor Specifications⎯Rotary Motors

Appendix B External Power-Dump Resistor Selection - 165 -
Resistor Specifications⎯Rotary Motors
Having determined the amount of energy to dump (E
R
), you can then
calculate the resistor specifications.
• Maximum resistance
• Peak dissipation
• Average dissipation
Maximum Resistance
This calculation determines the maximum value of resistance needed for the
external power-dump resistor. We recommend that you select a lower value
resistance, typically in the 22 to 100 ohm range.
Important — It is possible to overload an Aries drive or the combination of an Aries drive and
power dump resistor.
If at the end of the calculations you find the required resistor is less than allowed for your
specific Aries model, or requires a watt rating greater than the rated resistors available, do not
use the Aries drive in your application.
Aries drive models AR-01xx, AR-02xx, AR-04xx, AR-08xx, and AR-13xx, require external
resistance values of 22 Ohms or greater.
Aries drive models AR-20xE and AR-30xE require external resistance values of 8 Ohms or
greater
()
ω ⋅+
⋅⋅
==
LM
DTTRIP
R
JJ
tkV
I
V
R
Where
R
R
= maximum external power dump resistance (Ohms)
V = voltage across the resistor (V
TRIP
)
I = current through the resistor (drive current required to decelerate
the load)(Amps
rms
)
V
TRIP
= power dump trip DC voltage (400 volts for Aries drives)
k
T
= motor torque constant (Nm/Amp
rms
)
J
M
= rotor inertia (kg⋅m
2
)
J
L
= load inertia (kg⋅m
2
)
t
D
= deceleration time (Seconds)
ω = rotational speed in radians per sec (1 revolution/sec =
2⋅π⋅radians/sec)
Peak Dissipation
During a single deceleration, all the calculated power-dump energy (E
R
) must
dissipate in the external resistor. The external power-dump resistor then
slowly dissipates that energy as heat. This peak power must not exceed the
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