Understanding the Role of Electronics Repair and PLC Programming in Engineering Profiling

One year dedicated to electronics repair, electrical panel wiring, and PLC programming can certainly shape your career profile, but does it qualify you as a 'pseudo-electrical engineer'? This article will explore how to articulate your skill set and craft a compelling profile that highlights your qualifications.

The Evolution from Electronics Repair to Electrical Engineering

While it's true that engineers may not typically design their own PLC panels, these skills are indeed valuable in today's industrial settings. Overseeing the execution of your designs by electricians is a common responsibility, ensuring that your intentions are accurately conveyed through detailed drawings and specifications.

Key Components of Electrical Designs

To be effective in designing and implementing these systems, a thorough understanding of the essential components is crucial:

Transformers: Step down AC supply voltages to lower levels for safer and efficient distribution. Power Contacts: Manual enable/disable power with e-stop buttons. Terminals: Connect various devices and components in the system. Fuses or Circuit Breakers: Safeguard the system from excessive current draw. Grounding: Provide a path for current in case of an electrical fault. Enclosures: Protect equipment and users from accidental contact.

Wiring Diagrams and Motor Controllers

A well-drawn wiring diagram ensures that every component works in harmony. For instance, in a typical motor controller, a wiring diagram (Figure 1) outlines the connections and control configurations. Here’s a detailed breakdown of a motor controller:

AC Input: Connect the three-phase AC power (L1, L2, L3) to the terminals. Power Interruption: Connect the three-phase power to a power interrupter, then to a motor starter with thermal overload relays. Control Logic: Use push buttons to control the start and stop sequences. Start is 'normally open' and stop is 'normally closed' to ensure safety. Transformer: A step-down transformer supplies a lower voltage for control electronics, which then powers the system's rails. Stabilization: Ensure that the motor starter uses a spare contact to lock in the motor starter coil.

Standards and Safety Protocols

Building and designing these systems must follow specific standards including:

Hold Downs: Secure wires to prevent movement. Labels: Wire labels aid in troubleshooting. Strain Reliefs: Hold wires tightly into screw terminals to prevent accidental disconnection. Grounding: Critical for safety, each metal piece may need grounding wires.

Incorporating a PLC into Electrical Designs

Integrating a Programmable Logic Controller (PLC) into your design can make the system more sophisticated. Figure 5 below demonstrates a PLC based motor control system schematic, with the e-stop wired to cut power to all circuit devices, including the PLC. Ensuring that critical safety functions are hardwired this way is paramount.

By focusing on these key elements, you can effectively communicate your expertise, ensuring a robust and reliable electrical design that meets both engineering and safety standards. Your profile as a skilled electronic repair and PLC programming expert will undoubtedly attract the attention of potential employers and clients.