Specifications

8
FRICTION FORCE =
Weight (lbs) x coefficient of friction of
the bearing supports (µ)
Typical µ =
.001 for linear ball ways
= .005 for roller way bearings
= .005 for ball bearing splines
WEIGHT =
Weight of object being lifted*
*In horizontal applications the weight of
the load must be totally supported by
linear ways or bushings, the actuator
should push and pull the load only. The
actuator should not be side loaded.
STEP 3
Select the actuator which has the
optimum load and extension speed for
your application based on the
performance curves on pages 10 and 11.
Several actuators may meet your
requirements. Acme screw units are
generally less expensive but are limited
to a maximum of 50% duty cycle. If you
are unsure about your actual load/speed
requirements you may want to limit the
selection to actuators which provide
sufficient reserve capacity.
Warning! Do
not exceed the load/speed
performance curves. Exceeding the
curve will cause the motor to stall and
produce zero torque. This could result
in backdriving the actuator
.
To estimate the life of an actuator in your
particular application please refer to the
lead screw life chart on page 36.
Note: All load and speed curves
represent the typical performance based
on the appropriate Superior Electric
controls. The use of other controls may
reduce the performance of the actuators
significantly.
STEP 4
Determine actuator configuration: If
the load is less than 1000 pounds
determine the desired actuator
configuration- parallel or in-line. If the
load is above 1000 pounds the only
configuration available is parallel. If an
actuator is available as an in-line or
parallel version both part numbers will be
shown on the performance charts.
Parallel
In-line
Selection Procedures
Information needed:
Max.load = ______ lbs
Max speed = _____ inches per second
Duty cycle = _____ % on time verses
off time
Stroke length = ___ inches
Life = ___________ cycles, inches,
hours
Acceleration = ____ inches per second
2
Resolution = _____ inches
Back driving load = _____yes _____no
STEP 5
Select mounting options: choose the
mounting method for the actuator body-
rear clevis (not available on in-line
version), front flange, trunion, side
tapped holes or mounting feet. These
options are shown below and described
on page 6.
Rear clevis
Use on parallel
models only
Front flange
Trunion
Side tapped holes
Mounting feet
STEP 1
Determine actuator performance
characteristics: determine the load,
speed, duty cycle, life and stroke length.
If the application requires load holding in
the event of power failure there are two
reliable solutions: 1) A load holding brake
can be used on ball screws to prevent
backdriving in the event of a power
failure while providing the superior
performance of a ball screw.
Warning! A
load holding brake will not prevent a
ball screw actuator from backdriving
if it is overloaded and stalls
. 2) Acme
screws can be selected. Acme screws
are a lower cost alternative but do limit
actuator load, speed, duty cycle and life.
Acme screws will not backdrive even if
an actuator is overloaded and stalls.
Ball bearing screw Acme screw
STEP 2
Calculate Total Force (lbs)
TOTAL FORCE =
Acceleration Force + Friction Force +
Weight
Note: In horizontal applications the
weight component of the total force
should be zero.
ACCELERATION FORCE =
Mass x Acceleration
weight (lbs) velocity (in/sec.) 1 ft
________
x
______________
x
____
32.2 ft/sec
2
time to speed (sec) 12 in.