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How Stepper Motors Work

What are stepper motors and how do they work?

Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control.

Can stepper motors run continuously?

Stepper motors fall somewhere in between a regular DC motor and a servo motor. They have the advantage that they can be positioned accurately, moved forward or backwards one ‘step’ at a time, but they can also rotate continuously.

Where does a stepper motor can be used?

Commercially, stepper motors are used in floppy disk drives, flatbed scanners, computer printers, plotters, slot machines, image scanners, compact disc drives, intelligent lighting, camera lenses, CNC machines, and 3D printers.

Is a stepper motor AC or DC?

Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, one step at a time. With a computer controlled stepping you can achieve very precise positioning and/or speed control.

What is step angle?

Step angle is defined as the angle through which the stepper motor shaft rotates for each command pulse.

Why do stepper motors have 4 wires?

In each of the following cases a chassis ground lead is also pictured to ensure the motor is correctly grounded. While many motors take advantage of 6- and 8-wire configurations, the majority of bipolar (one winding per phase) stepper motors provide four wires to connect to the motor windings.

What is stepper motor with diagram?

Difference between Stepper Motor and Servo Motor Stepper Motor Servo Motor The motor which moves in discrete steps is known as the stepper motor. A servo motor is one kind of closed-loop motor that is connected to an encoder to provide speed feedback & position.

Are stepper motors High torque?

Although stepper motors aren’t notable for their ability to produce high torque at high speed, it is possible, in some applications, to achieve both. The motor’s pull-out torque curve shows the maximum torque that can be produced over the range of operating speeds.

What is the maximum rpm of a stepper motor?

Stepper motors are high pole count DC motors that are driven with a DC pulse train. Mechanical designers frequently create systems designed to use stepper motors at relatively high rpm based on the maximum motor speed rating (often 3000 rpm) and the motor torque vs. speed curves.

How do you control the speed of a stepper motor?

The speed of the rotors rotation in a stepper motor may be controlled in a variety of ways. Three such possibilities are through a series resistance, gearbox and voltage regulation. Each type has advantages over each other, and a methods implementation depends on the motor application and functionality.

How much torque can a stepper motor generate?

For example, a conventional size 34 stepper motor can produce 5.9 N-m of holding torque. The ultra-high-torque version of the same motor produces up to 9 N-m of holding torque. For a conventional motor to achieve this same torque rating would require a 31% longer motor.

What is the advantage of stepper motor?

Stepper Motors provide ruggedness, high reliability, simplicity of construction, allow for low maintenance, offer excellent response to starting/stopping/reversing and will work in many environments. Some of the top Stepper Motor disadvantages are in that the motors provide a low efficiency.

What is NEMA 17 stepper motor?

NEMA 17 stepper motors are those that have a 1.8 degree step angle (200 steps/revolution) with a 1.7 x 1.7 inch faceplate. NEMA 17 steppers typically have more torque than smaller variants, such as NEMA 14 and have a recommended driving voltage of 12-24V. These steppers are also RoHS compliant.

What is stepper motor rotor?

The stepper motor consists primarily of two parts: a stator and rotor. The rotor is magnetized in the axial direction so that, for example, if rotor 1 is polarized north, rotor 2 will be polarized south. The stator has ten magnetic poles with small teeth, each pole being provided with a winding.

What voltage is a stepper motor?

Stepper motors have a rated voltage and current. A typical stepper motor like our NEMA 17 might have a rated voltage of 2.8 Volts and a maximum current of 1.68 Amps. This basically means if you hook it up to 2.8 Volts it will draw 1.68 Amps.

What is a 12V stepper motor?

The 12V, 1.7A, 416 oz-in Geared Bipolar Stepper Motor has an integrated Planetary gearbox with a 26 103/121 :1 ratio. It comes with the rear shaft exposed, so you can mount an encoder or shaft coupler. At 1.7 Amps (maximum current), this stepper motor can produce a maximum torque of 77 kg-cm.

What is difference between DC and stepper motor?

The main difference is that, while stepper motors can push harder from rest, DC motors tend to have more sustained output. A DC motor cannot control the position of the rotor, while a stepper motor has the ability to control the position of the rotor.

How many steps does a stepper motor have?

A stepper mottor is a brushless, synchronous electric motor that converts digital pulses into mechanical shaft rotation. Every revolution of the stepper motor is divided into a discrete number of steps, in many cases 200 steps, and the motor must be sent a separate pulse for each step.

How many coils are there in stepper motor?

The Bipolar Stepper motor is similar to the unipolar motor discussed in previous projects. The bipolar consists of two coils, but there is no center tap. As a result of this, the bipolar motor requires a controller where the current flow through the coils can be reversed.