Tubular motors are the primary form of motorization used in roller shutters and roller blinds. They are also used extensively for retractable awnings, retractable screens, roof shutters, and other generic roll up applications.
Tubular motors are designed to fit within a rotating axle and thus appear tubular in appearance. They general comprise a metal or plastic tube with a drive wheel or flange at one end. At the most simple level the tubular motor comprises an AC electric motor that drives a series of planetary gear trains mounted into the 'tube' of the tubular motor.
The most common form of limit stop for tubular motors are mechanical limits that are set and remembered by using pulse counting on an encoder wheel inside the tubular motor. In a typical application this requires the installer to set the limits by manually running the tubular motor to the extreme limits and pressing a button on the motor, or perhaps on the motor remote control. Newer tubular motors include sophisticated electronics that provide this limit setting entired in electronics without needing to have access to the tubular motor. These newer models are also starting to include 'intermediate' stop positions to allow further flexibility. This allows the use to 'set and forget' a position that leaves a roller shutter half retracted, for example.
In a typical application the tubular motor is fitted within an axle. It is fitted such that the 'tube' of the tubular motor cannot rotate with respect to the axle that it is fitter within. The drive wheel or flange of the tubular motor usually includes a means of attachment to an axle, and is fixed such that the drive wheel cannot rotate with respect to the roller shutter. Thus when the tubular motor is powered the drive wheel does not rotate, but the 'tube' of the tubular motor does, resulting in the axle rotating.
Tubular motors are largely powered from the alternating current domestic electrical system. There are versions that can also run from low voltage direct current power systems such as batteries or solar panels.