Air tube disc clutches and brakes, High torque clutches, Low inertia brake selection – Wichita Clutch Low Inertia (LI) High Torque Clutch User Manual
Page 4

B
Air Tube Disc Clutches and Brakes
P-1100-WC 1/12
Wichita Clutch 800-964-3262 47
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Low Inertia Brake Selection
To properly size a brake, the total rotating inertia
reflected to the clutch and brake shaft must be
known.
Alternate shaft WR
2
referred to clutch shaft
=
Alternate Alternate shaft RPM
2
shaft WR
2
clutch shaft RPM
= 39,091
30
2
204
WR
2
referred to = 845.4 lb.ft
2
clutch-brake shaft @204 RPM
Total inertia = 78.2 lb.ft.
2
Back shaft WR
2
Clutch hub &
drive plate WR
2
from = 101.0 lb.ft.
2
Specification Table
Estimate brake WR
2
= 101.0 lb.ft.
2
(assume same as clutch)
Total WR
2
referred = 1,125.66 lb.ft.
2
to clutch-brake (Estimated)
Estimated time to stop:
= Start Angle 60
360º Crankshaft RPM
=
90º
60
= .5 sec.
360º
30
The deceleration torque is:
T = 12
WR
2
Brake RPM
32.2 9.5(t)
= 12
1125.6
204
32.2
9.5 (.5)
Deceleration Torque = 18,015 lb.in.
The HP / 100 RPM for this application is:
HP
=
Torque (lb.in.)
=
18,015
= 29 HP/100 RPM
100 RPM 630 630
Consult the Specification Table on pages 36-37
to select a brake based on torque and HP/
100 RPM. Under "Duty C", an ATD-214 brake
has 32 HP/100 capacity and 55,250 lb.in.
torque. The rotating inertia of an ATD-214
Low Inertia Brake is 11 lb.ft.
2
. Therefore, the
actual rotating inertia reflected to brake is
1035.6 lb.ft.
2
.
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The actual
= 12
1035.6 204
deceleration torque 32. 2 9.5
= 16,575 lb. in.
Required air pressure is:
Brake
=
Brake required torque x (100 PSI)
Catalog rated torque @ 100 PSI
=
16,575 lb. in.
x 100
55,250 lb. in.
= 30 PSI minimum
This application has 100 PSI available.
The average heat HP each stop
=
(Brake Torque)
x RPM x 1/2
63,000
=
16,575
x 204 x .5
63,000
= 26.8 HP
Friction area necessary to absorb heat = heat HP
=
Heat HP
=
26.8
= 39 in.
2
Absorbtion rate for .5 sec.
.7 .7 (see page 174 )
An ATD-214 Low Inertia Brake has 316 in.
2
of
friction lining available to absorb heat
generated by stopping. Maximum bore for
an ATD-214 Low Inertia Brake is 4-1/8 inches.
Based on the given application data and
the following calculations, an ATD-224 Low
Inertia High Torque Clutch and ATD-214
Low Inertia Brake have been selected as
having sufficient torque and heat dissipation
capacity with minimum diameter and
sufficient bore capacity.
Note:
These application examples are for
preliminary sizing only. Contact a
Wichita Sales Engineer or the
factory for final selection.
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High Torque Clutches