Relais Thermique : Choix de l'appareil pour protéger un moteur (partie 4)

Thermal Overload Relay Selection Guide (Part 4)

This video is the fourth installment in a micro-series focused on thermal overload relays. It provides a detailed guide on how to select the appropriate relay from a manufacturer’s catalog to protect an electric motor.

Key Technological Concepts and Product Features

Thermal Overload Relay Selection Criteria

• Compatibility: Ensure the relay is compatible with the associated motor contactor, whether it is independent or mounted underneath the contactor.
• Tripping Class: Choose the desired tripping class, which defines the relay’s tripping time.
• Rated Current: Use the rated current of the motor, obtained from the motor’s nameplate, as a basis for selection.

Catalog Usage

• Learn how to read catalog pages to identify the correct thermal overload relay model and its adjustable current range.
• Example scenario:
  • Motor connected in a star configuration at 400V.
  • Motor current: 3.84A.
  • Selected relay: LRD08, adjustable between 2.5 and 4A, matching the motor current.

Accessories

• Identification of compatible accessories such as terminal blocks for mounting.
  • Options include snap-on mounting on a 35mm DIN rail or screw fixing.
• Reference to catalog pages for accessory compatibility, for example, the LAD7B16 terminal block.

Tutorial/Guide Elements

The video demonstrates a step-by-step process including:

1. Extracting the motor current from the nameplate.
2. Matching the motor current to a thermal overload relay’s adjustable setting range.
3. Verifying compatibility between the relay and the contactor.
4. Selecting and referencing appropriate accessories for installation.

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Presenter

The video is presented by an expert instructor who guides viewers through the thermal overload relay selection process.