2016年5月19日星期四

Types of Steppers

The stepper drive delivers electrical energy towards the motor in response to low-level signals in the manage method. Input signals towards the stepper drive consist of step pulses along with a path signal. 1 step pulse is needed for each step the motor would be to take. This really is accurate no matter the stepping mode. So the drive might need 200 to 101,600 pulses to create 1 revolution from the shaft. Probably the most commonly-used stepping mode in industrial applications will be the half- step mode in which the motor performs 400 actions per revolution. At a shaft speed of 1800 rpm, this corresponds to a step pulse frequency of 20kHz. Exactly the same shaft speed at 25,000 actions per rev demands a step frequency of 750 kHz, so motion controllers controlling microstep drives should be in a position to output a a lot greater step frequency.

You will find a wide selection of stepper kinds, a few of which need extremely specialized drivers. For our purposes, we'll concentrate on stepper motors that may be driven with generally accessible drivers. They are: Permanent Magnet or Hybrid steppers, either 2-phase bipolar, or 4-phase unipolar.

Motor Size

One of the first things to consider is the work that the motor has to do. As you might expect, larger motors are capable of delivering more power. stepper motor drivers come in sizes ranging from smaller than a peanut to big NEMA 57 monsters.

Most motors have torque ratings. This is what you need to look at to decide if the motor has the strength to do what you want.

NEMA 17 is a common size used in 3D printers and smaller CNC mills. Smaller motors find applications in many robotic and animatronic applications. The larger NEMA frames are common in CNC machines and industrial applications.

The NEMA numbers define standard faceplate dimensions for mounting the motor. They do not define the other characteristics of a motor. Two different NEMA 17 motors may have entirely different electrical or mechanical specifications and are not necessarily interchangeable.

Unipolar vs. Bipolar

Unipolar drivers, always energize the phases in the same way. One lead, the "common" lead, will always be negative.  The other lead will always be positive. Unipolar drivers can be implemented with simple transistor circuitry. The disadvantage is that there is less available torque because only half of the coils can be energized at a time.

A two phase bipolar motor has 2 groups of coils. A 4 phase unipolar motor has 4. A 2-phase bipolar motor will have 4 wires - 2 for each phase. Some motors come with flexible wiring that allows you to run the motor as either bipolar or unipolar.

Bipolar Stepper Motor Driver

The Bipolar Stepper Motor Driver additional board is designed to operate bipolar stepper motors in full-, half-, quarter- and eight-step modes. It is available as a stand-alone device or connected to the microcontroller. For connecting the Bipolar Stepper Motor Driver to the microcontroller on the development system, it is necessary to use a flat cable with IDC female connector that should be connected to some development system’s I/O port.

Leadshine's Stepper Motor Driver item line is compatible with most NEMA frame sizes, 08, 11, 15, 17, 23 and 34 stepper motors. Every Stepper Motor Driver series offers numerous various attributes to cover a wide variety of stepper motor/driver applications. These Stepper Motor Drivers are competitively priced, with out sacrificing overall performance or item life. All Leadshine Stepper Motor Drivers are single axis, and variety in the smallest at 0.two Amps to eight.0 Amps (model dependent). Leadshine's complete line of stepper motor drivers consists of step divisors from 400 to 51,200spr, and voltage specifications ranging from 12 - 123VDC (model dependent). All Stepper Motor Drivers provide low voltage and over-voltage protection. Other choices accessible are RS232, RS422, RS485, RS785 and may bus. All Leadshine stepper motor/driver goods are 100% tested for function and reliability.

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