Summary of "Diagrama Completo da Partida Direta de Motor - Curso de Elétrica Industrial Grátis"

Summary of the Video: “Diagrama Completo da Partida Direta de Motor - Curso de Elétrica Industrial Grátis”

This video is the first lesson in a series aimed at teaching how to design, dimension, and assemble a direct start system for a three-phase electric motor, specifically for industrial electrical applications. The instructor, Victor Vitoriano, guides viewers through the fundamental concepts, control and power diagrams, and the logic behind direct motor starting.

Main Ideas and Concepts

Introduction to the Series and Instructor

The series covers the entire process of dimensioning and assembling a direct start system for a three-phase motor.
Victor Vitoriano, an instructor at Electrical Classroom, leads the course.
Lessons include design, dimensioning, panel assembly, and activation.

What is a Direct Start?

Direct start means applying the motor’s nominal voltage directly to the motor terminals.
Provides full starting torque, beneficial for loads requiring high starting force.
Drawback: Starting current can be 8 to 10 times the nominal current.
Alternative starting methods (star-delta, soft starters) may be used for intermittent or less demanding applications.

Application Example: Wire Drawing Machine

The motor is coupled to a wire drawing machine, which requires high torque to pull and shape metal wire.
Direct start is chosen to ensure maximum torque at startup.

Control and Power Diagrams

Use of CAD and simulation software to create the diagrams.
Power circuit includes:
- Three-phase power supply plus ground.
- Circuit breaker or fuse (F11).
- Magnetic switch (contactor).
- Thermal relay (F7) for motor overload protection.
- Three-phase motor connection depends on supply voltage.
Grounding is essential for safety.

Explanation of Components and Logic

Circuit Breaker / Fuse

Protects installation from short circuits and overloads.

Thermal Relay

Protects the motor specifically from overload.

Magnetic Contactor

Acts as a magnetic switch to connect/disconnect the motor from power using a low-voltage control signal (usually 24V).

Control Circuit

Uses 24V for safety and logic control.
Includes emergency stop button (mushroom type, normally closed contact).
Activation (start) and stop buttons for normal operation.
Sealing (holding) contact on the contactor to maintain motor operation after releasing the start button.

Safety Logic

Emergency stop immediately cuts power.
Thermal relay trips on overload, stopping the motor.
Circuit breaker trips on short circuit or overload.

Signaling Elements

Signal lights (red and green) indicate motor status (running, stopped, emergency).
Labels on the panel help operators understand the machine state.

Operation Logic

Pressing start button energizes the contactor coil, closing power contacts and starting the motor.
Sealing contact keeps the contactor energized after releasing the start button.
Pressing stop button or emergency stop de-energizes the contactor coil, stopping the motor.
Thermal relay or circuit breaker trips will also stop the motor for protection.

Next Steps

Future lessons will cover device sizing, including proper configuration of thermal relays and circuit breakers depending on motor size.

Methodology / Instructions Presented

Designing the Power Circuit:
- Connect three-phase power supply and ground.
- Insert circuit breaker or fuse for installation protection.
- Add magnetic contactor for motor switching.
- Include thermal relay for motor overload protection.
- Connect the motor terminals according to supply voltage.
- Ground the motor casing for safety.
Designing the Control Circuit:
- Use 24V control voltage for safety and logic.
- Connect emergency stop button first in the circuit (normally closed contact).
- Connect thermal relay contact next for overload protection.
- Add start (normally open) and stop (normally closed) buttons.
- Connect the coil of the magnetic contactor.
- Add sealing (holding) contact in parallel with the start button to maintain motor operation after releasing start.
- Include signal lights (red and green) connected to the contactor contacts to indicate motor status.
Operation and Simulation:
- Press start button → energizes contactor coil → motor starts.
- Release start button → sealing contact keeps motor running.
- Press stop button or emergency stop → de-energizes contactor → motor stops.
- Thermal relay or circuit breaker trips → motor stops automatically.
- Signal lights indicate motor running or emergency status.
Safety Considerations:
- Use contactors to reduce risk of electric shock by controlling high voltage with low voltage.
- Proper grounding of motor and panel.
- Emergency stop button must be easily accessible.
- Use thermal relay and circuit breaker for motor and installation protection.

Speakers / Sources Featured

Victor Vitoriano – Primary instructor and presenter, teacher at Electrical Classroom.
Ian – Demonstrates the wire drawing machine process (briefly mentioned).
Cuian – Assists with zooming in on diagram details (briefly mentioned).

This video provides a comprehensive introduction to direct motor starting, focusing on practical wiring diagrams, component functions, and safety logic essential for industrial electricians.