True/False
Indicate whether the
statement is true or false.
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1.
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Auxiliary contacts are intended to control large amounts of current.
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2.
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Relays and contactors that are operated by direct current generally contain
laminated cores.
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3.
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Hysteresis loss is often referred to as molecular friction.
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4.
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Vacuum contactors enclose their load contacts in a sealed vacuum chamber.
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5.
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When the coil of an alternating current relay or contactor is energized, it will
require less current to pull the armature in than to hold it in.
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Completion
Complete each
statement.
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6.
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Relays and contactors operate on the ____________________ principle.
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7.
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All solenoids that operate on alternating current must have a(n)
____________________ coil.
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8.
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The continuous change of both amplitude and polarity of the magnetic field
causes currents to be induced into the metal core material; these currents are called
____________________ currents.
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9.
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Contactors are equipped with contacts intended to connect high current loads to
the power line; these large contacts are called ____________________ contacts.
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10.
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Mechanically held contactors and relays are often referred to as
____________________ contactors or relays.
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Short Answer
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11.
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What are relays?
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12.
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Why is it that bridge contacts can control more voltage than clapper
types?
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13.
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How is optoisolation achieved?
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14.
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What is a reason for sealing load contacts inside a vacuum chamber?
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15.
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What are coil clearing contacts?
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