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Rockwell Automation SA3100 AutoMax Distributed Power System User Manual

Page 53

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Glossary

A-9

phase sequence reversal: a reversal of the normal phase sequence of the AC power
supply. Can be accomplished by the interchange of any two lines on a three-phase
system.

phase shift: the phase angle difference between two sinusoidal signals of the same
frequency. Also, the displacement between corresponding points in similar wave
shapes, expressed in degrees lead or lag.

phase, single (AC circuits): a circuit energized by a single AC source. Usually
supplied through two wires; the currents in these two wires counted outward from the
source differ by 180 degrees, or a half cycle.

phase, three (AC circuits): a combination of three AC signals which differ in phase by
one-third of a cycle (120 degrees). Usually supplied through three or four wires.

polyphase (AC circuits): an AC circuit consisting of more than two intentionally inter-
related conductors.

quadrant: in power rectification, used to designate the functional characteristics of
converters. There are four types:

Form A - Type I: single converter unit in which the DC current can flow in one
direction and is incapable of “inverting” energy from the load to the supply;
operates in 1 quadrant.

Form B - Type II: double converter unit in which the DC current can flow in either
direction but which is not capable of inverting energy from the load to the AC
supply; operates in quadrants 1 and 3 only.

Form C - Type III: single converter unit in which the DC current can flow in one
direction only and which is capable of inverting energy from the load to the AC
supply; operates in quadrants 1 and 4.

Form D - Type IV: a double converter unit in which the DC current can flow in
either direction and which is capable of inverting energy from the load back to the
AC supply; operates in all four quadrants.

rectification: the process by which electrical energy is converted from an alternating-
current circuit to a direct-current.

rectifier: a type of converter that changes AC to DC. Usually consists of an anode and
a cathode; conducts current in one direction only.

regeneration: the characteristic of a motor to act as a generator when the CEMF is
larger than the drive’s applied voltage (DC drives) or when the rotor synchronous
frequency is greater than the applied frequency (AC).

regenerative braking: see braking.

regulator: in general, a piece of hardware or software that regulates a quantity such
as voltage, power, speed, etc., at a set value or between certain close limits.

resolution: the least value of a measured quantity which can be detected.