Hitachi SJ2002 Series Instruction Manual page 235

Isolation Transformer
Jogging Operation
Jump Frequency
Line Reactor
Momentum
Multi-speed Operation
Motor Load
NEC
NEMA
Open-collector Outputs
Power Factor
A transformer with 1:1 voltage ratio that provides electrical isola-
tion between its primary and secondary windings. These are
typically used on the power input side of the device to be protected.
An isolation transformer can protect equipment from a ground fault
or other malfunction of nearby equipment, as well as attenuate
harmful harmonics and transients on the input power.
Usually done manually, a jog command from an operator's panel
requests the motor/drive system to run indefinitely in a particular
direction, until the machine operator ends the jog operation.
A jump frequency is a point on the inverter output frequency range
that you want the inverter to skip around. This feature may be used
to avoid a resonant frequency, and you can program up to three
jump frequencies in the inverter.
A three-phase inductor generally installed in the AC input circuit of
an inverter to minimize harmonics and to limit short-circuit current.
The physical property of a body in motion that causes it to remain
in motion. In the case of motors, the rotor and attached load are
rotating and possesses angular momentum.
The ability of a motor drive to store preset discrete speed levels for
the motor, and control motor speed according to the currently
selected speed preset. The Hitachi inverters have 16 preset speeds.
In motor terminology, motor load consists of the inertia of the
physical mass that is moved by the motor and the related friction
from guiding mechanisms. See also Inertia.
The National Electric Code is a regulatory document that governs
electrical power and device wiring and installation in the United
States.
The National Electric Manufacturer's Association. NEMA Codes
are a published series of device ratings standards. Industry uses
these to evaluate or compare the performance of devices made by
various manufacturers to a known standard.
A common logic-type discrete output that uses an NPN transistor
that acts as a switch to a power supply common, usually ground.
The transistor's collector is open for external connection (not
connected internally). Thus, the output sinks external load current to
ground.
A ratio that expresses a phase difference (timing offset) between
current and voltage supplied by a power source to a load. A perfect
power factor = 1.0 (no phase offset). Power factors less than one
cause some energy loss in power transmission wiring (source to
load).
SJ200 Inverter
2
A–5