While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
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A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…
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Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…
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A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
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Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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Some problem-solving techniques are unique to quantitative problems, involving mathematical calculations. In…
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To summarize some of the key points and concepts for teaching: Do not waste class time transmitting facts to…
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To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
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The three “elementary” particles of matter comprising all atoms are electrons, protons, and…
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(Will be addressed in future versions of this book)
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Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
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A hand switch is exactly what the name implies: an electrical switch actuated by a person’s hand motion.…
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There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
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A very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
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