Rockwell Automation 1398-DDM-xxx ULTRA 100 Series Drives Installation Manual - Manual (Page 284)

Publication 1398-5.2 – PDF 1997
F-2 Dynamic Braking Resistor Selection
For this type of response, 98% of the energy will be dissipated in 4
time constants. Therefore the average power for each dynamic braking
event can be calculated as:
Equation 1 is used in equation 2 and 3 to put the power in terms of the
motor parameters and the dynamic braking resistance (i.e.,
independent of the load inertia).
Intro
P t
( )
J
L
J
M
+
( )ω
o
2
2
τ
------------------------------ e
2 – t τ ⁄
1.154
K
E
K
T
ω 2
o
R 2R
L
+
( )
------------------------- e
2t – τ ⁄
= =
2
( )
Intro
3
( )
P
AVE
1
2
--- J
M
J
L
+
( )ω
o
2 1
4
τ
-----
 
 
0.144
K
E
K
T
ω
o
2
R 2R
L
+
( )
------------------------- = =