Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 193)

Glossary-6
Frequency The number of periodic cycles per unit of time.
Front of a Motor The end opposite the coupling or driving pulley (NEMA). This is sometimes called
the opposite pulley end (O.P.E.) or commutator end (C.E.).
Full-load Torque The full-load torque of a motor is the torque necessary to produce rated horsepower
at full-load speed.
Gate The control element of an SCR (silicon controlled rectifier) commonly referred to
as a thyristor. When a small positive voltage is applied to the gate momentarily,
the SCR will conduct current (when the anode is positive with respect to th
cathode of the SCR). Current conduction will continue even after the gate signal
is removed.
General-purpose Motor This motor has a continuous Class “B” rating and design, listed and offered in
standard ratings with standard operating characteristics and mechanical
construction for use under unusual service conditions without restriction to a
particular application or type of application (NEMA).
Hard Contacts Any type of physical switching contacts.
Hardware Mechanical, electrical, and electronic components and assemblies.
Horsepower A measure of the amount of work that a motor can perform in a given period of
time.
Induction Moto An alternating current motor in which the primary winding on one member
(usually the stator) is connected to the power source. A secondary winding on the
other member (usually the rotor) carries the induced current. There is no physical
electrical connection to the secondary winding, its current is induced.
Inertia A measure of a body’s resistance to changes in velocity, whether the body is at rest
or moving at a constant velocity. The velocity can be either linear or rotational.
The moment of inertia (WK
2
) is the product of the weight (W) of an object and the
square of the radius of gyration (K
2
). The radius of gyration is a measure of how
the mass of the object is distributed about the axis of ration. WK
2
is usually
expressed in units of ft.-lb.
2
.
Input Device A digital or analog device such as a limit switch, pushbutton, pressure sensor, or
temperature sensor, that supplies input data through an input circuit to a
programmable controller.
Interlock 1. A switch or other device that prevents activation of a piece of equipment when
a protective door is open or some other hazardous condition exists.
2. Software that inhibits execution of other software logic unless certain defined
conditions exist.
Intermittent Duty A motor that never reaches equilibrium temperature (equilibrium), but is permitted
(INT) to cool down between operations. For example, a crane, hoist or machine tool
motor is often rated for 15 or 30 intermittent duty.