How to select a brake – Rockwell Automation 1305 DYNAMIC BRAKES User Manual
Page 4
1305 Dynamic Brake
4
1305-5.11 May, 1999
Step 5 — Determine the Maximum Generated Braking Torque
How to Select a Brake
(continued)
where:
TQ
B
= The required braking torque.
N
2
= The motor’s maximum speed.
P
M
= kW
P
M
=
TQ
B
×
N
2
——————
7,000
P
M
= [ ]
×
[ ]
————————
Three factor limit the application
The first is the brake assembly rating
P
T
— The peak power the brake
assembly can absorb at any instant regardless of the time limit.
The second is the average power that the brake assembly can absorb
during one braking duty cycle —
P
A
.
The third is the duty cycle or the number of times the brake assembly
can be operated over a given period of time —
DC
.
P
M
must be less than or equal to the brake assembly rating listed in
table 1
. If
P
M
exceeds the
P
T
value shown, the corresponding
drive/brake configuration will not be able to produce the braking
torque required for your application, and the drive will trip on an
overvoltage fault. Increasing the decel time
t
2
, reducing the load inertia
wk
2
L
, or doing both will lower
TQ
B
and
P
M
.
table 1
Drive Output Ratings
P
T
HP
kW
Dynamic Brake Kits
kW
230VAC
2
1.5
1305-KAA12
1.7
3
2.2
460VAC
1/2
0.37
1305-KBA03
1.7
3/4
0.55
1
0.75
2
1.5
1305-KBA06
1.7
3
2.2
1305-KBA06
5
4
1305-KBA09
3.4
Step 6 — Determine the Average Power Generated in One Cycle
where:
TQ
B
= The required braking torque.
N
1
= The motor’s minimum speed.
N
2
= The motor’s maximum speed.
P
A
= kW
P
A
= TQ
B
×
[N
1
+ N
2
]
————————
14,000
P
A
= [ ]
Ч
[ + ]
———————————
14,000