Allen-Bradley PowerFlex 70 Reference Manual

2-4 Determining Dynamic Brake Requirements
Step 2 Total Inertia
J
T
= Total inertia reflected to the motor shaft
(kg-m
2
or WK
2
in lb.-ft.
2
)
J
m
= Motor inertia (kg-m
2
or WK
2
in lb.-ft.
2
)
GR = Gear ratio for any gear between motor and load
(dimensionless)
If the gear ratio is 2:1 then
J
L
= Load inertia (kg-m
2
or WK
2
in lb.-ft.
2
)
1.0 lb.-ft.
2
= 0.04214011 kg-m
2
Calculate Total Inertia:
Record Total Inertia:
Determine Values of Equation Variables
J
T
=
J
T
J
m
GR
2
J
L
×()+=
GR
Load Speed
Motor Speed
-----------------------------=
GR
1
2
-- 0.5==
J
T
oooooooooo[]oooooooooo oooooooooo×()+=

Allen-Bradley PowerFlex 70 Specifications

General

Brand	Allen-Bradley
Model	PowerFlex 70
Category	Controller
Language	English