Group: DANAHER MOTION
Deltran Clutches & Brakes Catalog 2009  100 / 156 Pages
98 www.thomsonlinear.com
Clutch Selection
Step 1
For clutch applications with a specific
acceleration time requirement, first calculate
the dynamic torque (TD) required to
accelerate the load using the inertiatime
equation:
TD = 0.1047 (I x w) / t + D
where I = rotational load inertia in lbinsec2
units, w = differential slip speed in RPM,
t = time to speed, and D = load drag torque
reflected to the clutch. Next convert to
static torque by multiplying by 1.25. Skip
to Step 3.
Step 2
For clutch applications requiring only
an ability to accelerate a load, calculate
the appropriate static torque using the
horsepowerRPM equation:
TS = 1.25 x 63000 x (HP x K) / w
where HP = horsepower, K = service factor,
and w = differential slip speed in RPM
OR refer to the charts in the engineering
guidelines section.
Step 3
Select a clutch model from the catalog
with a static torque rating greater than
the required torque (service factor dependent).
Verify that the selected clutch fits
into the available application envelope
and mounting configuration.
Note: When engaging a clutch dynamically
(under load at speed), careful consideration
must be given to proper energy
dissipation. Calculate the total energy
dissipated per minute:
E = (Ek + Es) x N
where Ek = kinetic energy, Es = slip energy,
and N = cycle rate. If the total energy
dissipation is more than allowable (see
performance data tables), then consider
using a larger series clutch.
General Notes
In some applications it may be necessary
to consider clutch or brake inertia
and engagement time in calculating load
acceleration. If the inertia or engagement
time of the clutch or brake selected
represents more than 10% of the load
inertia or acceleration time, use the above
referenced Inertiatime equation to solve
for acceleration time (t), using an inertia
equivalent to the sum of the load inertia
and the clutch or brake inertia (see performance
data tables). Then verify that
the sum of the acceleration and clutch
or brake engagement times is still within
the required acceleration time for the
application.
For more information on other key factors
that greatly affect clutch or brake life,
such as ambient temperature, slipspeed
and load energy, please contact us at
15406333400.
Brake Selection
Step 1
Determine if the application requires a
static (holding) or dynamic (stopping)
brake.
Step 2
For static brake applications, determine
the required static torque to hold the load
under worst case conditions, considering
system drag. Skip to Step 5.
Step 3
For dynamic braking applications with a
specific stopping time requirement, first
calculate the dynamic torque necessary
to decelerate the load, using the inertiatime
equation:
TD = (0.1047 (I x w) / t)  D
where l = total system inertia lbinsec2,
w = shaft speed in RPM, t = time to zero
and D = load drag. Next multiply by 1.25 to
convert to static torque. Skip to Step 5.
Step 4
For those dynamic braking applications
requiring only an ability to stall a load,
calculate the appropriate static torque
using the horsepowerRPM equation:
TS = 1.25 x 63000 x (HP x K) / w
where HP = horsepower, K = service factor
and w = RPM OR refer to the charts
found on page 99.
Step 5
Select a brake model from the catalog
with a static torque rating greater than
the required torque (service factor dependent).
Verify that the selected brake fits
into the available application envelope
and mounting configuration.
Note: When braking dynamically, careful
consideration must be given to proper
energy dissipation. Calculate the total
kinetic energy dissipation per cycle (Ek),
and compare this to the allowable braking
energy (Eb) based on the frequency
of engagement (N) given in the Energy
Dissipation Chart on page 143. If the total
kinetic energy dissipation per cycle is
more than allowable, given the frequency
of engagement, then consider using a
larger series brake.
How to Select
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