Title: Lab 4-2: Control Relay as a Master Control Relay
Course: Electrical Motor Controls (Sandbox) > Section: Module 4: Control Relays and Timing Relays, 20 hr

Introduction

Background

Control relays are often used as a Master Control Relay (MCR). In an electrical control system, an MCR is used to provide a way to remove power from a section of an electrical system, often for safety reasons.

In the circuit shown below, the user presses the "System Power On" button, which, in turn, provides power to the motor control circuit that is in the lower part of the ladder diagram. If the system power is not on, the motor cannot be started.

Assignment

Using your knowledge of control relays, you will build a circuit with a master control relay. Two lights are provided in the circuit: one lights up when the system is on, and the other lights up when the motor is running (more specifically, when the motor starter coil is energized).

The following video will walk you through the steps of building the circuit according to the schematic shown below.

Lab Instructions

1. Watch the video introduction to this lab.
2. Draw a schematic diagram, in Automation Studio or by hand, that represents a circuit that will operate as described in the video.
3. Unplug the Motor Controls trainer.
4. Build the circuit on the Motor Controls trainer.
5. Plug in and turn on the Motor Controls trainer.
6. Test the circuit.
7. When the system is on, a light illuminates, and the other lights up when the motor the motor starter coil is energized).

Submission

To complete this lab, submit a 30-second video following the criteria found in the rubric. If you are working with another student, each of you must record and submit your own video.

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