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A Stepper Motor System consists of three basic elements, often combined with some type of user interface (Host Computer, PLC or Dumb Terminal):Indexers - The Indexer (or Controller) is a microprocessor capable of generatingstep pulses and direction signals for the driver. In addition, the indexer is typically required to perform many other sophisticated command functions.Drivers - The Driver (or Amplifier) converts the indexer command signals into the power necessary to energize the motor windings. There are numerous types of drivers, with different voltage and current ratings and construction technology. Not all drivers are suitable to run all motors, so when designing a Motion Control System the driver selection process is critical.Stepper Motors - The stepper motor is an electromagnetic device that converts digital pulses into mechanical shaft rotation. Advantages of step motors are low cost, high reliability, high torque at low speeds and a simple, rugged construction that operates in almost any environment. The main disadvantages in using a stepper motor is the resonance effect often exhibited at low speeds and decreasingtorque with increasing speed.[

A stepper motor (or step motor) is a brushless DC electric motor that divides afull rotation into a number of equal steps. The motor's position can then be commanded to move and hold at one of these steps without any feedback sensor (an open-loop controller), as long as the motor is carefully sized to the application

A DC motor is a mechanically commutated electric motor powered from direct current (DC). The stator is stationary in space by definition and therefore its current. The current in the rotor is switched by the commutator to also be stationaryin space. This is how the relative angle between the stator and rotor magneticflux is maintained near 90 degrees, which generates the maximum torque.DC motors have a rotating armature winding (winding in which a voltage is induce

d) but non-rotating armature magnetic field and a static field winding (windingthat produce the main magnetic flux) or permanent magnet. Different connectionsof the field and armature winding provide different inherent speed/torque regulation characteristics. The speed of a DC motor can be controlled by changing thevoltage applied to the armature or by changing the field current. The introduction of variable resistance in the armature circuit or field circuit allowed speedcontrol. Modern DC motors are often controlled by power electronics systems called DC drives.The introduction of DC motors to run machinery eliminated the need for local steam or internal combustion engines, and line shaft drive systems. DC motors can operate directly from rechargeable batteries, providing the motive power for thefirst electric vehicles. Today DC motors are still found in applications as small as toys and disk drives, or in large sizes to operate steel rolling mills and

paper machines.

A servomotor is a rotary actuator that allows for precise control of angular position.[1] It consists of a motor coupled to a sensor for position feedback, through a reduction gearbox. It also requires a relatively sophisticated controller,

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often a dedicated module designed specifically for use with servomotors.Servomotors are used in applications such as robotics, CNC machinery or automated manufacturing.

Servomotors are generally used as a high performance alternative to the steppermotor. Stepper motors have some inherent ability to control position, as they have built-in output steps. This often allows them to be used as an open-loop position control, without any feedback encoder, as their drive signal specifies thenumber of steps of movement to rotate. This lack of feedback though limits theirperformance, as the stepper motor can only drive a load that is well within itscapacity, otherwise missed steps under load may lead to positioning errors. Theencoder and controller of a servomotor are an additional cost, but they optimise the performance of the overall system (for all of speed, power and accuracy) relative to the capacity of the basic motor. With larger systems, where a powerful motor represents an increasing proportion of the system cost, servomotors havethe advantage.

Many applications, such as laser cutting machines, may be offered in two ranges,the low-priced range using stepper motors and the high-performance range usingservomotors.[2]