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A stepper motor is a brushless, synchronous electric motor that converts digital pulses into mechanical shaft rotation. Its normal shaft motion consists of discrete angular movements of essentially uniform magnitude when driven from sequentially switched DC power supply.
What is a stepper motor used for?
The stepper motor is used for precise positioning with a motor, such as hard disk drives, robotics, antennas, telescopes, and some toys. Stepper motors cannot run at high speeds, but have a high holding torque.
What do stepper motors control?
A stepper motor converts a train of input pulses into a precisely defined increment in the mechanical shaft position, where each pulse moves the shaft through a fixed angle. Stepper motor control provides this input train of pulses to command the motor to move to the desired position or at the desired speed.
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.
Why is it called stepper motor?
Stepper motors are so named because each pulse of electricity turns the motor one step. Stepper motors are controlled by a driver, which sends the pulses into the motor causing it to turn.
How powerful is a stepper motor?
As a result, it is unusual to find stepper motors capable of producing more than 1,000 to 2,000 ounce inches of torque. Stepper motors also have performance limitations. You can think of a stepper motor as a spring-mass system.
How do stepper motors fail?
Short Circuit. One of the major problems with a stepper motor is complete motor failure. This problem is caused by excessive current being sent to the device by the power supply. A short circuit in the wiring from the power supply to the motor cause this problem with the stepper motor.
Does a stepper motor need an encoder?
=> Among positioning motors, stepper motors do not have a built-in encoder. For this reason, they require no adjustment and are strong against low rigidity. Their movements are stable regardless of fluctuating loads.
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 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.
Do stepper motors have brushes?
Stepper motors are different from ordinary DC motors in at least four important ways. The first difference you notice is that they have no brushes or commutator (the parts of a DC motor that reverse the electrical current and keep the rotor—the rotating part of a motor—constantly turning in the same direction).
Why are stepper motors so expensive?
Due to the restricted space, the windings on most small in-runners have to be installed by hand. This is a difficult and time-consuming and job, which makes them more expensive than machine wound brushed motors.
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.
Do stepper motors have feedback?
Stepper motors are inherently open-loop devices. They don’t require feedback because each pulse of current delivered by the drive equals one step of the motor (or a fraction of a step in the case of microstepping). Stepper motors with closed-loop control can provide an alternative to servo motors.
Can a stepper motor 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.
Are stepper motors fast?
Generally speaking the top speed of a stepper motor is approximately 1000rpm. If you need to go above this speed but still require intelligent control of the motor you should consider a brushless DC motor and controller (brushless ESC).
Is a stepper motor A servo motor?
Stepper motors have a high pole count, usually between 50 and 100. Servo motors have a low pole count – between 4 and 12. This difference in pole count means that stepper motors move incrementally with a consistent pulse in a closed loop system. Servo motors require an encoder to adjust pulses for position control.
Can you damage a stepper motor?
1 Answer. Stepper motors (depending on how they are driven) are generally always on. You change the polarity of the signal driving the coils in a sequence to control movement. So leaving the motor powered is not going to damage it.
Can a stepper motor wear out?
Since a stepper motor has no brushes to wear out, its life usually far exceeds that of other mechanical components in a system. If the motor is run at or near its rated torque or thrust, life will be affected.
How do I know if my stepper motor is bad?
Most inexpensive motors use glue to hold the shaft to the rotor, and most quality steppers will use grooving along with adhesive. To test the motor, first use an ohmmeter. It will indicate if a winding is burnt up and what type of step motor you have, usually a bipolar or unipolar.
