Circuit Breakers and Stepper Motors: Functionality & Types

Electrical Protection Devices and Stepper Motors Explained

Thermal Switches

These are automatic switches that react to overcurrent slightly higher than the rated value, ensuring disconnection in a short circuit. To ensure sufficient lead time for disconnection, they take advantage of the deformation of a bimetallic strip, which curves as a function of the heat produced by the current passing through it.

Magnetic Switches

These are switches that react to high overcurrents, operating in a short enough time so as not to harm the network or associated devices. To initiate disconnection, they utilize the movement of an iron core in a magnetic field proportional to the value of the circulating current.

Magneto-Thermal Switches

A circuit breaker is a device capable of interrupting the electric current in a circuit when it exceeds certain maximum values. Its operation is based on two effects produced by electrical current flow: magnetic and thermal (Joule effect). The device therefore consists of two parts, an electromagnet and a bimetallic plate, connected in series and through which current flows to the load.

Residual Current Devices (RCDs)

These automatic switches prevent dangerous currents from flowing through the human body. The dangerous effects that may occur depend on the current intensity and its path.

Stepper Motors: Principles and Types

A stepper motor is an electromechanical device that converts a series of electrical impulses into discrete angular movements, meaning it can move a specific number of degrees (steps) depending on its control inputs. The stepper motor behaves similarly to a digital-to-analog converter and can be governed by impulses from logic control systems. This motor presents the advantages of high accuracy and repeatability in terms of positioning.

Among its main applications are:

• Precise positioning systems
• Robotics
• Machine tools
• Digitally controlled systems

There are 3 basic types of stepper motors:

• Variable reluctance motor
• Permanent magnet motor
• Hybrid stepper motor

Variable Reluctance Stepper Motor

The variable reluctance motor refers to an electric motor of the stepper type, whose operation is based on variable reluctance by a soft iron, toothed rotor which tends to align with the poles of the stator windings. It can achieve very small steps.

Permanent Magnet Stepper Motor

A permanent magnet stepper motor is a type of electric stepper motor. It is also known as PMSM (Permanent Magnet Synchronous Motor). They are extensively used in servo electric drives for positioning, robotics, machine tools, and elevators.

Hybrid Stepper Motor

A hybrid stepper motor refers to an electric motor of the stepper type, whose operation is based on the combination of the two other types of stepper motors: the variable reluctance motor and the permanent magnet motor.