1. Make sure you always provide a return force to the SQUIGGLE motor
screw.
The motor requires that a few of grams of force be applied to the
screw, to ensure that
the threads are properly engaged for proper operation of the motor.
If this "return force" or "loading force" is not present, the motor may stall,
exhibit intermittent motion, or otherwise not operate to
specification. This will not damage the motor, but will
result in poor operation of your system. Please see the reference
design example in the
SQL-1.8 or SQL-RV-1.8 SQUIGGLE Motor Manual for more information
(registration required).
NOTE: do not attach the screw tip to the load; see #3 below.
2. Proper return force prevents motor screw drift due to strong
external vibrations.
The SQUIGGLE motor is very robust and can easily survive strong
vibration and shock. To use this feature to your advantage, it is a
good practice to mount the motor with the return force in the
direction of your locked (or closed fail-safe) position. This way if
the system is subject to strong vibration, the mechanism will remain
locked. An example is shown below.
3. Do not side-load the motor screw.
The screw should be allowed to rotate freely, pushing against a
low-friction surface on the load. A
common mistake is to fix a component such as an end cap or disc on
the screw, and then to apply a side load to the component. Such a
side load will shorten the life of the motor and may prevent the
screw from rotating — reducing performance or stalling the motor.
This can be avoided by decoupling the component from the screw. Note in the reference design
example how the stages are not directly connected to the motor.
4. Avoid friction in the system.
The SQUIGGLE motor has a high thrust force which easily
accommodates a few grams of return force plus the mass or load of the
system you are moving. Any friction will reduce the total load you
will be able to move with the motor, so in designing your system it
is always better to minimize the friction between moving parts. Be
particularly careful to prevent friction from side-loading (see #3).
5. Avoid running the SQUIGGLE motor into a hard stop.
The motor will not be damaged by running it into a hard stop.
More often it simply backloads the screw until the force is higher
than 30 grams, at which point the motor stalls. In these cases the
motor may sometimes remain jammed against the hard stop, unable to
free itself. The easiest way to prevent this is to use limit
switches to stop the motor at the ends of travel. There are several
different types of limits that may be used including position
sensors. New Scale has also made available to its customers a
proprietary way to prevent jamming purely through the mechanical
design of the screw. A reference design is available in the SQL-RV-1.8
and SQL-1.8 SQUIGGLE Motor
Manual (registration required) or
contact our applications engineering team for more information.
6. NSD-1202 only: Use the proper master clock frequency of 20MHz.
NOTE: New Scale recommends the newer SQL-RV-1.8 reduced
voltage SQUIGGLE motor with NSD-2101 driver. The NSD-2101 driver
features a built-in oscillator and does not require an external
clock.
When using an SQL-1.8 motor and NSD-1202 driver, the accuracy of
switching frequency and phase shift will be defined depending on
master clock frequency of the NSD-1202, specified at 20MHz. Lower
master clock frequencies give higher deviations, therefore the 20MHz
master clock frequency is strongly recommended. Using a lower
frequency could result in reduced performance over the operating
temperature range as well as potential variation in performance from
motor to motor in your motion system. If you need to use the
NSD-1201 with a lower master clock frequency, please consult our
applications engineering team to learn more about the frequency
doubling functionality and other options available.
Additional resources
Please register to
download additional information including the
SQL-RV-1.8 and SQL-1.8 Series SQUIGGLE Motors User Manual or
consult the applications engineering team at New Scale Technologies:
email
sales@newscaletech.com
or call (585) 924-4450. We will be happy to work with you to
ensure your design’s success.
New Scale engineers can assist OEM customers with integration
structure design, create customized motor housings, or design
complete application-specific modules (including drive electronics
and
miniature position sensors) to fit your requirements. See our
custom
engineering page for more information.
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