Wichita Clutch LK Brake - Manual (Page 7)

Air Tube Disc Clutches and Brakes
28 Wichita Clutch 800-964-3262 P-1100-WC 1/12
Air System Data
PSI pressure
Inflation
Clutch air pressure during inflation can
be closely estimated by the following:
Clutch pressure = P
1
( 1 – ) PSI
(inflation)
This equation is accurate from 5% up
to 95% P
1
.
P
1
= Line pressure to clutch PSI
K and U = coefficients for specific
clutch and air pressure from
Spec i fi ca tion Table
e = Naperian base log
t
o
= Time at initiation of signal for
inflation sec.
t
d
= Time delay of air system – sec.
Exhaust
Clutch air pressure during exhaust
can be closely estimated by the
fol low ing:
Clutch pressure = (P
1
) (R) (E-t) v PSI
(exhaust)
R, E and V = coefficients for specific clutch
and air pressurefrom Spec i fi ca tion
Table
t
e
= Time to exhaust = E from
Spec i fi ca tion Table
t = Time variable – seconds. In the ex -
haust equa tion “t” cannot exceed
the value of “E” sec.
Shown are some of the air systems used
on Wichita clutches. These systems are
ac cept able for remote op er a tion where
clutch reaction time is not important.
Faster clutch re ac tion time is ac com
plished as in di cat ed in the
di a gram by lo cat ing the flow
control valve, if re quired,
and the so le noid valve as
close as possible to the
roto-cou pling. Where
clutches are located on long shafts, the
use of quick release valves on the clutch
will fa cil i tate faster clutch response.
Overlap
A typical clutch-brake torque curve for
a single backshaft press (cyclic ap pli -
ca tion) would appear as shown below.
Time (sec.)
t
Oc
= time at which disengaged clutch
receives signal
t
Cc
= time of clutch en gage ment
t
1c
= time of clutch full inflation
t
OB
= time at which disengaged brake
receives signal
t
Bc
= time of brake engagement
t
1B
= time of brake full exhaust
t
2
= overlap time at which clutch and
brake are both engaged
1
e
Kt u