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What is a unipolar stepper motor

What is a unipolar stepper motor?

A unipolar stepper motor is one of the two basic types of two phase stepper motors. The unipolar motor has one winding with a center tap per phase. Typically the center tap is made common, giving three leads per phase and six leads for the typical two phase motor. Mostly these two phase commons are internally joined making the motor have five leads. A micro controller or stepper controller can be used to control drive transistors in the right order, creating an ease of operation making the unipolar stepper motor the cheapest way to gain precise angular movements.

Related Questions

How is the rated insulation voltage (Ui) of Proximity sensors tested?

Sensors with a supply voltage of up to 250 VAC are tested as follows: Class 1 (with earth terminal) at 1500 VAC. Class 2 (with double insulation, without earth terminal) at 3000 VAC.

How are proximity sensors protected against inductive loads?

Unless otherwise specified, DC proximity sensors are protected against inductive over voltage by use of a surge diode or a zener diode. AC proximity sensors require an external load protector.

What does PPR stand for when used with encoders?

I relation to encoders PPR stands for Pulse Per Revolution. In rotational motion for rotational pulse and motion per inch or millimeter for linear motion.

Additional Information

How does a Coupling work?Importance of High-Precision Couplings
Not only are couplings and line shafts required to transmit torque from driving to driven elements but they must also compensate for misalignment between two shafts. Precision couplings ensure a backlash and maintenance free transmission of torque throughout their operations unlike standard couplings. This precision coupling is so precise because of the tight tolerances and dimensional accuracy measured in hundredths of a millimeter of the individual precision coupling components. Despite the large variety, precision couplings can be divided into two main groups: torsionally rigid couplings and vibration damping couplings. The torsionally rigid couplings are often used in the X-Y axis of machine tools whereas vibration damping couplings are mainly used in spindle motors or conveyor units.

Torsional Rigidity
Torsional Rigidity describes the rigidity of a coupling when it is subjected to a torsional load. If the torque is to high and the maximum torsional value of the coupling is exceeded, the coupling will no longer be strong enough to transmit the acting rotational force, the unit "torsional rigidity" (Nm/rad) reflects this relation. Each coupling has a permissible angle of twist with most rigid couplings having a maximum angle of twist of less than 0.05 degrees, and vibration damping coupling having a maximum angle of twist of less than 5 degrees. If the admissible angle of twist is not exceeded, the coupling will have an infinite life.

Spring Stiffness
The spring stiffness is the counterforce exerted by the coupling in case of differentiated position of the axes in an axial, radial, and lateral direction. The spring stiffness is measured in units of N/mm. If, according to the manufacturer, the axial spring stiffness of the coupling is 30 N in the case of an axial displacement of 1 mm. These additional forces should always be taken into account when selecting bearings or other drive system components.

Zero Backlash
Zero backlash means that there is no empty space or "play" when the rotational speed, direction of rotation, or torque changes. This does not mean, however, that there is no angle of twist. Zero backlash is very important for the service life of bearings as well as driving and driven mechanisms.

Compensation for Misalignment
Due to layout and assembly inaccuracies, there are misalignments, however small, between the driving and driven shaft in almost all applications. They are caused by tolerances in the dimensional accuracy of the connected components and by external factors affecting the drive system, such as temperature and other atmospheric conditions. Three types of misalignment are generally distinguished. First, there is axial misalignment. This is caused by changes in length along the longitudinal axis of the driving and the driven shaft which are typically made of metal. Second there is angular misalignment, which is mostly caused by inaccuracies in the assembly of the connected components. Standard couplings can normally compensate for angular misalignments of up to 2 degrees. Unlike axial misalignment, angular misalignment places a high load on the coupling, because the load on the compensation element is much greater in this case. Lateral misalignment places the highest stress on the coupling. The two shafts are displaced parallel to one another. The compensation element (the metal bellows or the elastomer insert) is therefore stressed by two opposing angular bends. The alignment of the driving and driven components has a major influence on the service life of the couplings as well as the entire drive system. If the maximum misalignment values stated by the manufacturer are not exceeded, the couplings will have an infinite life and will not require maintenance at regular intervals.

Torsional Rigidity
Torsional Rigidity describes the rigidity of a coupling when it is subjected to a torsional load. If the torque is to high and the maximum torsional value of the coupling is exceeded, the coupling will no longer be strong enough to transmit the acting rotational force, the unit "torsional rigidity" (Nm/rad) reflects this relation. Each coupling has a permissible angle of twist with most rigid couplings having a maximum angle of twist of less than 0.05 degrees, and vibration damping coupling having a maximum angle of twist of less than 5 degrees. If the admissible angle of twist is not exceeded, the coupling will have an infinite life.

Spring Stiffness
The spring stiffness is the counterforce exerted by the coupling in case of differentiated position of the axes in an axial, radial, and lateral direction. The spring stiffness is measured in units of N/mm. If, according to the manufacturer, the axial spring stiffness of the coupling is 30 N in the case of an axial displacement of 1 mm. These additional forces should always be taken into account when selecting bearings or other drive system components.








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