Stepper motors offer a number of advantages over regular DC motors.
First of all, their different composition and functioning enable precise positioning and controlled motion and they also deliver higher torque at lower speed, making them ideal for applications requiring these characteristics.
If a gear reduction is coupled to the motor, it can change output speed and torque, according to the desired performance. It is recommended to accurately choose the motor and gearbox combination to ensure that the system matches the parameters of the load and application and to minimize the possibility of loss of speed or motor stall.
When to use stepper motors with gear reduction
Stepper motors are among the best choices for applications requiring high torque at a low speed. For example, we can find these motors in machines like printers and scanners, which need to move parts accurately while maintaining smooth motion.
The addition of a gear reduction allows to increase the motor input speed to optimize its performance and reach the required parameters for the application. The reduction ratio determined by the gearbox can be defined by the ratio between the input speed and the output speed.
Considering stepper motors in particular, the coupling with a gear reduction can increase motor performance by augmenting torque at load, decreasing the inertia ratio between load and motor and reducing oscillations. Consequently, it allows the use of a smaller motor size while still ensuring optimum performance.
For example, if we have a motor that has a maximum output torque of 5 Nm and we want it to exert 10 Nm, we can use a gearbox with a 2:1 reduction ratio.
Another common application is decreasing a motor’s speed while increasing its output power. If you have a motor that rotates at 3000 rpm and you want it to rotate at 1000 rpm instead, once again an appropriate gearbox must be applied, in this case with a 3:1 reduction ratio.
4 reasons for using a stepper motor gear reduction
In some applications which require a fine and more precise regulation of output speed and torque with minor variations of input control or supply current, a stepper motor with gear reduction can be used to achieve maximum flexibility.
As mentioned before, there are the main 4 reasons why to choose a stepper motor with gear riduction:
- Decreases the inertia ratio between load and motor. If the value of the load inertia is higher than the value of the motor inertia, it is possible to experience problems in load and step control and sometimes motor stall. To avoid this condition, it is necessary either to use a motor with a higher load inertia, and therefore of greater size, weight and cost, or to add a gearbox that can significantly decrease the inertia ratio between motor and load
- Increases torque at load. In a combined motor and gearbox system, the latter multiplies the motor torque in proportion to the reduction ratio while reducing the speed
- Lowers motor oscillations. In the presence of a gearbox, increasing the speed the motor moves outside its resonant frequency range and avoids oscillation and vibration, decreasing the risk of motor stall or step loss
- Allows the use of a smaller motor. The torque generated by the motor and gearbox combination is higher and can meet the requirements of many applications, thus avoiding the need for larger and more expensive motors to achieve the same torque.
Applications of a stepper motor with gear reduction
In applications requiring smooth motion, low speed, and moderate torque such as robotic arm, stepper motor and gearbox coupling is ideal to achieve the desired result.
The stepper motor is used in numerous fields, and coupling it with a gearbox increases its application possibilities. As mentioned in the previous article, by using a driver, it is possible to manage the motor with high accuracy, greater flexibility, and sophisticated control.
In the industrial field we find these gearmotors in a variety of machinery such as CNC machines, photovoltaic systems, 3D printing, and robotics, while in the consumer sector in appliances such as printers, scanners, video surveillance systems, air conditioners, lighting, and home automation.
