CNS STEPPER MOTOR

A stepper motor is an electromechanical device it converts electrical power into mechanical power. Also it is a brushless, synchronous electric motor that can divide a full rotation into an expansive number of steps. The motor’s position can be controlled accurately without any feedback mechanism, as long as the motor is carefully sized to the application. Stepper motors are similar to switched reluctance motors. Unless you will be using external stepper motor drivers, choose motors with rated current of at least 1.2A, and at most 2.0A for the Duet 0.6 and Duet 0.8.5, or 3A for the Duet 2. Plan to run each stepper motor at between 50% and 85% of its rated current. Size: Nema 17 is the most popular size used in 3D printers. Nema 14 is an alternative in a highly-geared extruder. Use Nema 23 motors if you cannot get sufficient torque from long Nema 17 motors. Avoid motors with rated voltage (or product of rated current and phase resistance) > 4V or inductance > 4mH. C...

The most popular design of linear actuators, the external nut configuration is simple, compact, and offers a high level of design flexibility. In the external nut configuration, the shaft of the stepper motor is replaced with a lead screw. In a typical application, the motor is fixed in position and an apparatus is attached to the nut. As the lead screw rotates, the external nut travels along the length of the screw, providing linear motion. The length and the pitch of the lead screw of linear actuator are highly customizable, making the external nut configuration useful for a wide variety of applications. Numerous mounting options paired with the many types of nuts available help tailor this particular linear actuator to best fit a user’s specific situation. In addition, the external nut configuration helps achieve greater acceleration and maximum speeds than other configurations while also offering greater efficiency in terms of power consumption. There are a few limitations...

Stepper and servo motors differ in two key ways, in their basic construction and how they are controlled. Stepper motors have a large number of poles, magnetic pairs of north and south poles generated either by a permanent magnet or an electric current, typically 50 to 100 poles. In comparison, servo motors have very few poles, often 4 to 12 in total. Driving a stepper motor to a precise position is much simpler than driving a servo motor. With a stepper motor, a single drive pulse will move the motor shaft one step, from one pole to the next. Since the step size of a given motor is fixed at a certain amount of rotation, moving to a precise position is simply a matter of sending the right number of pulses. In contrast servo motors read the difference between the current encoder position and the position they were commanded to and adjust the current required to move to the correct position. With today's digital electronics, stepper motors are much easier to control than servo moto...

Stepper motors are sensitive to the performance of their power supplies. Stepper motor power supplies can affect: When sizing a power supply, keep the above points in mind and remember that the drive type and method of operation influence which power supply is most suitable. Manufacturers offer integrated linear stepper motors that combine drives and controllers. This one by AMCI takes a power supply of 3.4 A. When sizing a power supply, ensure that enough power is available when needed — but remember that an overly large supply wastes power. Note that when it comes to a motor’s rated voltage versus voltage supply, there’s not much concern unless the power supply runs near the drive’s maximum rating. If this is indeed the case, then there’s a risk when decelerating the motor. The load’s momentum stores energy that must be dissipated. The drive can’t do this, so the energy returns to the CNC power supply . This in some cases can overload the power supply and make it fail. So e...

We get a lot of questions about what stepper motors and CNC power supplies to use, so we've started this page. A lot of this information is scattered over the rest of the wiki, but it's nice to pull it together in one place. General NEMA17 versus NEMA23 TinyG is capable of delivering 2 amps per winding, and 2.5 amps per winding with cooling. Given that, we have never found a NEMA17 that would not work with TinyG, and almost every NEMA23 we have tried will work if rated up to about 3 amps per winding (with the caveat that you might not get full power if it calls for more than 2.5 amps). We also routinely run NEMA34 's, but not at full power and therefore not in high mechanical load situations. What's with the motor's rated voltage? The question comes up - can I run a motor with a rated voltage of 4.2 volts (for example) with a 24 volt supply? Will this burn out the motor? The motor's rated voltage is irrelevant and can be ignored. Any stepper motor...