BEX100

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BEX100 Basic Electricity

• Relays
• (Magnetic Switches)

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Objectives

• Know the definition of a relay
• Understand relay operating principles
• Properly test relay operation

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Relay Principles

• A relay may also be called an electromagnetic
  switch
• Relays use a low amperage circuit to control a
  high amperage circuit
• The low amperage circuit controls an
  electromagnetic device
• The electromagnetic device closes/opens the
  high amperage circuit

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Relay Operation
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Typical 4 Pin RelayISO RELAY
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Typical 5 Pin RelayISO RELAY
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Typical 5 Pin RelayPin Identification
HALF ISO
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Relay Applications
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Relay Applications
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Relay Applications
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Relay Applications
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Testing Relay Operation

• Relays can be tested using
• A test light
• A continuity light
• A DVOM
• A jumper wire

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Testing Procedures
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Testing Procedures
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RELAY DIAGNOSIS

• SHOULD HAVE POWER ON TWO CONNECTIONS IN KEY ON
  DEVICE OFF POSITION (ISO TERMINALS 30 AND 85 OR
  86)
• RELAYS ARE MOST ALWAYS ACTIVATED WITH GROUND
• LISTEN FOR CLICK WHEN ACTIVATED BETTER YET CHECK
  OUTPUT VOLTAGE ( ISO PIN 87)

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WHEN ALL ELSE FAILS...

• EXCHANGE SUSPECT RELAY WITH ANOTHER RELAY OF THE
  SAME NUMBER IN THE RELAY CENTER

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LETS REVIEW...

• WHY ARE RELAYS CALLED MAGNETIC SWITCHES?
• HOW MUCH CURRENT DOES THE CONTROL CIRCUIT USE?
• HOW MUCH CURRENT DOES THE LOAD CIRCUIT USE?
• NAME SOME ADVANTAGES OF USING RELAYS?

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LETS REVIEW..

• WHAT IS AN ISO RELAY?
• WHAT IS A HALF ISO RELAY?
• HOW CAN RELAYS BE TESTED?
• WHAT RESISTANCE SHOULD THE RELAY COIL READ?
• WHAT SHOULD THE NC CONTACTS OF A RELAY READ?
• WHAT SHOULD THE NO CONTACTS OF A RELAY READ?

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THANK YOUTHANK YOU VERY MUCH!!
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Elizabethtown Technical CollegeBEX100 Basic
Electricity