Rockwell Automation FlexPak 3000 DC Drive Version 4.3 - Manual (Page 95)

Glossary Of Terms D-1
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Glossary Of Terms
altitude: The atmospheric altitude (height above sea level) at which the motor or drive
will be operating.
armature: The portion of the DC motor that rotates.
rated full load current: Armature current in amperes.
armature Resistance: Measured in ohms at 25 degrees Celsius (cold).
base speed: The speed which a DC motor develops at rated armature voltage and
rated field current with rated load applied. Typically nameplate data.
constant speed: Used to describe a motor which changes speed only slightly from a
no-load to a full-load condition.
DC motor: A motor using either generated or rectified DC power. A DC motor is
usually used when variable speed operation is required.
DB: Dynamic braking.
default value: Parameter values that are stored in the drive's Read Only Memory
(ROM).
direct current: A current that flows only in one direction in an electrical circuit. It may
be continuous or discontinuous and it may be constant or varying.
drive: Power converting equipment supplying electrical power to a motor.
efficiency: The ratio of mechanical output to electrical input. It represents the
effectiveness with which the motor converts electrical energy to mechanical energy.
field: A term commonly used to describe the stationary (stator) member of a DC
motor. The field provides the magnetic field with which the mechanically rotating
(armature or rotor) member interacts.
horsepower: The measure of the rate of work. One horsepower is equivalent to lifting
33,000 pounds to a height of one foot in one minute. The horsepower of a motor is
expressed as a function of torque and RPM. For motors, the following approximate
formula may be used:
HP = T x RPM / 5250;where HP = horsepower,
T = Torque (in lb/ft), and
RPM = revolutions per minute.