Improved performance promises new applications for stepper motors
David Melder discusses emerging application areas for steppers
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Advances in stepper motors in recent years are opening up their potential for use in applications where previously they would hve been too expensive or lacking ruggedness. New designs using stronger rare earth magnets
and with higher IP ratings, combined with price levels that were unobtainable in the past, are opening up new possibilities for these motors.
One area where the latest generation of stepper motors has great potential is in valve control. Applications in central heating control systems for example could benefit from the new motors which could replace traditional valve controls.
For example
, a new unipolar stepper motor from Astrosyn can produce over 8 kg of thrust over a linear movement of 7 mm. It is suitable in heating and ventilating systems, where it can act as a three-way valve control. The compact unit is sealed against water ingress to IP55 standards
. Its power and reliability will give it a significant advantage over existing systems.
Such motors can be subjected to severe weather conditions of course, and these products from Astrosyn are rated for temperatures from -40C to +80C, with a lifetime
of 15 years. At least 50kg of thrust is produced, sufficient to overcome icing in winter months. The
units use a new material developed for the linear thruster, with almost twice the performance of brass.
The motors can also be used in telephone base stations, where their compact size is an advantage in restricted conditiions. They can be used to control microwave filters,
from traditional cavity designs to the latest E-plane models, where the motors can adjust the RF filtering.
A third application for the new stepper motors is in the control of inexpensive solar arrays.
By controlling their altitude and azimuth, solar reflectors can be automaticaly moved to follow the motion of the sun so that the light
is concentrated on a stationary photoelectric transducer.
Once again their reliability and relatively low cost make these motors ideal for this purpose.
These applications are examples of the potential of the new generation of stepper motors, with their lower cost, greater reliability and higher performance.
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Another application for the new generation of stepper motors is in 3G mobile telephone masts. A remote controlled electrical down-tilt module uses a stepper motor that can be connected to the positioning rod used to adjust the angle of the antennas. This enables the multiple antennas on a mast to be independently steered to ensure maximum uniformity of signal and reduce the possibility of distortions between neighbouring antennas.