Hitachi X200 Series Free-run Stop, Insulated Gate Bipolar TransistorIGBT a semiconductor

A−4

Appendix A

Free-run Stop	A method of stopping a motor, caused when the inverter simply turns
	OFF its motor output connections. This may allow the motor and load
	to coast to a stop, or a mechanical brake may intervene and shorten
	the deceleration time.
Frequency Setting	While frequency has a broad meaning in electronics, it typically
	refers to motor speed for variable-frequency drives (inverters). This is
	because the output frequency of the inverter is variable, and is
	proportional to the attained motor speed. For example, a motor with a
	base frequency of 60 Hz can be speed controlled with an inverter
	output varying form 0 to 60 Hz. See also Base Frequency, Carrier
	Frequency, and Slip.
Harmonics	A harmonic is a whole number multiple of a base of fundamental
	frequency. The square waves used in inverters produce high
	frequency harmonics, even though the main goal is to produce lower-
	frequency sine waves. These harmonics can be harmful to electronics
	(including motor windings) and cause radiated energy that interferes
	with nearby electronic devices. Chokes, line reactors, and filters are
	sometimes used to suppress the transmission of harmonics in an
	electrical system. See also Choke.
Horsepower	A unit of physical measure to quantify the amount of work done per
	unit of time. You can directly convert between horsepower and Watts
	as measurements of power.
IGBT	Insulated Gate Bipolar Transistor(IGBT) – A semiconductor
	transistor capable of conducting very large currents when in
	saturation and capable of withstanding very high voltages when it is
	OFF. This high-power bipolar transistor is the type used in Hitachi
	inverters.
Inertia	The natural resistance a stationary object to being moved by an
	external force. See also Momentum.
Intelligent Terminal A configurable input or output logic function on the Hitachi
	inverters. Each terminal may be assigned one of several functions.
Inverter	A device that electronically changes DC to AC current through an
	alternating process of switching the input to the output, inverted
	and non-inverted. A variable speed drive such as the Hitachi L200 is
	also called an inverter, since it contains three inverter circuits to
	generate 3-phase output to the motor.
Isolation	A transformer with 1:1 voltage ratio that provides electrical isolation
Transformer	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.