Air tube disc clutches and brakes, Spring-set air release brakes – Wichita Clutch LI SSB - Low Inertia Spring Set Brake User Manual
Page 2
B
Air Tube Disc Clutches and Brakes
P-1100-WC 1/12
Wichita Clutch 800-964-3262 59
Low Inertia Spring-Set Brake
To properly select a brake, the total
rotating inertia, WR
2
, must be reflected
to the brakeshaft.
Application Data:
Refer to page 45, except, cyclic op er a tion—
7 CPM, and 218 Very Low Inertia Clutch.
Alternate Shaft WR
2
referred to clutch shaft =
(Alternate Shaft WR
2
)
(
Alternate Shaft RPM
)
2
Clutch Brake Shaft RPM
WR
2
referred to clutch-brake shaft
= (39,091)
(
30
)
2
204
WR
2
referrred to clutch-brake shaft
= 845.4 lb.ft.
2
@ 204 RPM
Crank Shaft WR
2
= 845.4 lb.ft.
2
Clutch-Brake Shaft WR
2
= 78.2 lb.ft.
2
Clutch Hub and Drive Plate WR
2
from Specification Table = 14.7 lb.ft.
2
(page 61)
Est. Brake WR
2
= 14.7 lb.ft.
2
Est. Total WR
2
= 953.0 lb.ft.
2
Brake Selection:
Stopping angle of crank shaft = 120° = Ø
b
Use 90° for calculation
Estimated time to stop:
t =
(
Ø
b
) (
60
)
360° crank shaft RPM
=
(
90
) (
60
)
= .5 sec.
360 30
Deceleration Torque
= (12)
(
WR
2
)(
clutch-brake RPM
)
32.2 (9.5) (t)
= (12)
(
953
)(
204
)
32.2 (9.5) (.5)
= 15,250 lb.in.
HP/100 RPM
= 15,250 = 24 HP/100 RPM
630
From duty chart (page 23) “Group B”
for spring-set brake (SS):
214 SS Brake is rated @ 28 HP/100 RPM
90% torque rating = 24,800 lb.in.
WR
2
of 214 SS VLI Brake = 4.5 lb.ft.
2
, therefore
deceleration torque calculation is correct.
*Average heat horsepower to clutch & brake.
Avg. heat HP = (Total WR
2
) (RPM
2
) (CPM)
1.9 x 10
8
=
(953) (41,616) (7)
= 1.45 HP
1.9 x 10
8
*Check with factory for heat capacity.
Note:
This application example is for preliminary
sizing only. Contact a Wichita Sales Engineer
or the factory for final se lec tion.
Spring-Set Air Release Brakes
Selection