LEARNING MODULE 19:
STARTERS AND CONTACTORS
Cutler-Hammer
STARTERS
WELCOME
Welcome to Module 19, which is about starters, devices that control the use of electrical power to equipment, usually a motor.
As the name implies, starters “start” motors. They can also stop them, reverse them, accelerate them, and protect them.
Starters are made from two building blocks, contactors and overload protection:
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Contactors control the electric current to the motor. Their function is to repeatedly establish and interrupt an electrical power circuit.
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Overload Protection protects motors from drawing too much current and overheating, from literally “burning out.”
=
STARTER
+
CONTROLLER
OVERLOAD PROTECTION
FIGURE 1. A STARTER IS MADE UP OF A CONTROLLER
(MOST OFTEN A CONTACTOR) AND OVERLOAD PROTECTION
Like the other modules in this series, this one presents small, manageable sections of new material followed by a series of questions about that material. Study the material carefully, then answer the questions without referring back to what you’ve just read.
You are the best judge of how well you grasp the material. Review the material as often as you think necessary. The most important thing is establishing a solid foundation to build on as you move from topic to topic and module to module.
A Note on Font
Styles
Key points are in bold.
Glossary terms are underlined and italicized the first time they appear.
Viewing the
Glossary
You may view definitions of glossary items by clicking on terms and words that are underlined and italicized in the text. You may also browse the Glossary by clicking on the Glossary bookmark in the left-hand margin.
1
STARTERS
WHAT YOU
WILL LEARN
We’ll start by talking about the building blocks of a starter: the contactor and overload protection. We will then conclude with a discussion on starters. Here are the topics that we will cover:
Section Title
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3
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Knife Blade Switch
3
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Manual Controller
4
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