Description 42BYGH47-401A


RepRap 42 two-phase four-wire stepper motor - the most important power component of the -3D printer
Simply speaking, a stepper motor is a motor that precisely controls the amount of rotation by a current pulse, which is supplied by a stepper motor drive unit. The so-called "step" is also a current pulse, each "step" is a fixed length, so the stepper motor is suitable for applications that require precise positioning. There are two types of stepping motors: bipolar and unipolar. RepRap is basically available in two ways. We only need to pay attention to the following main technical parameters, so we will not choose the wrong motor.

Specifications:


Weight: 0.4kg
Phase: Phase 2
Step Angle: 1.8 5% degrees / step
Voltage: 12V
Current: 1.2A / phase of
Resistance: 10.0 10% / phase
Inductance: 20 20% MH / phase
Lead Style: AWG26 UL1007
With 4 lead
Holding torque: 48N.cm
Braking torque: 2.6N.cm maximum
Insulation cllass: B
Rotor torque: 68g.cm2
Pressure: 1500V AC1MIN
Surface temperature: 80 C
Size: 42 * 42 * 47mm

42BYGH47-401A Wiring Colour Codes:
RED.........Phase A
BLUE........Phase A Return
GREEN......Phase B
BLACK......Phase B Return



NEMA
The bipolar stepper motor used in RepRap is of the NEMA 17 type, and this code represents only a size specification that meets US electronics manufacturing standards. It defines the surface dimensions of the motor (the "footprint" in plan view) without defining the length. NEMA 17 means 1.7x1.7 inches and NEMA 23 is 2.3X2.3 inches. But not the larger the size, the greater the torque, and the NEMA 14 may be more powerful than the NEMA 23. Dimensions are not the most important, but choosing a medium-sized motor can meet both performance requirements and lightweight design.

Step angle
Stepper motors for Prusa require a step angle of 1.8, in other words, 200 steps per revolution, since 1.8 x 200 = 360. You can choose a smaller angle and more precise angle, but if the angle is larger, you need to use it with the speed reduction gear.

Current and power
When selecting a stepper motor, you need to pay attention to the rated voltage and current parameters, which are typically 2.8V and 1.7A. As long as the stepper motor drive unit can control the current output, it is theoretically possible to use any supply voltage that is higher than the rated voltage of the motor. If the drive unit cannot control the current, it is necessary to use a supply voltage close to the rated voltage, otherwise the motor will be at risk of overheating.

Holding torque
For motors on three axes, the recommended minimum holding torque is 13.7 N-cm (0.137 Nm or 19.4 oz-in). For Wade extrusion nozzles, more torque is required because of the need to squeeze the plastic material, which is recommended to be at least 40 N-cm (0.4 Nm). In principle, the five stepper motors are not identical, but for the two on the Z axis, it is best to have the same specifications.

size
All Mendel printers default to a motor shaft diameter of 5 mm. According to the standard NEMA 17 motor specifications, the hole spacing between the two mounting holes should be 31 mm. This information should be helpful to students who have collected old motors.

Wiring
Stepper motors are available in several wiring sizes, and are available in 4, 6, and 8 pins for RepRap applications. There are also 5 pins, but they are not available for 3D printers.

Heat dissipation
The technical parameters of most stepper motors indicate that the temperature of the coil can rise by 80 C after power-on, which means that the operating temperature can reach 100 C! Therefore, the plastic bracket for mounting the motor has the possibility of being melted, so only partial load can be used. PLA is more resistant to heat than ABS, starting at around 60 to 65 C, and ABS is about to start at 105 to 120 C, so the plastic parts of the heat-resistant part of 3D printers are best printed using ABS. .

The advantage is that I still have a little more torque. The specifications of this motor are as follows:
Motor length: 48mm line length 1 meter
Holding torque: 5Nm
Rated voltage: 3.6V
Step angle: 1.8
Resistance per phase: 3
Inductance per phase: 5mH
Current per phase: 1.2A
Rotary shaft diameter: 5mm (with flat cut surface, easy to install without slipping)
4-pin design: red, blue, green and black
This motor has a current of 1.2A and an output torque of 5Nm. The performance is very good. At least the operating temperature is much lower than most 1.7A motors. You need a total of five, one for each of the X-axis and Y-axis, two for the Z-axis, and one for the extrusion nozzle.