Hitachi L100 Instruction Manual page 27

1–10
Intelligent Functions and Parameters
Braking
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Introduction to Variable-Frequency Drives
Much of this manual is devoted to describing
how to use inverter functions and how to config-
ure inverter parameters. The inverter is micropro-
cessor-controlled, and has many independent
functions. The microprocessor has an on-board
EEPROM for parameter storage. The inverter's
front panel keypad provides access to all
functions and parameters, which you can access
through other devices as well. The general name
for all these devices is the digital operator, or
digital operator panel. Chapter 2 will show you
how to get a motor running, using a minimal set
of function commands or configuring parame-
ters.
The optional read/write programmer will let you
read and write inverter EEPROM contents from
the programmer. This feature is particularly
useful for OEMs who need to duplicate a particu-
lar inverter's settings in many other inverters in
assembly-line fashion.
In general, braking is a force that attempts to slow or stop motor rotation. So it is associ-
ated with motor deceleration, but may also occur even when the load attempts to drive
the motor faster than the desired speed. If you need the motor and load to decelerate
quicker than their natural deceleration during coasting, we recommend installing an
optional dynamic braking unit. See pages 5–2 and 5–5 for more information on the
BRD–E2 and BRD–EZ2 braking units. The L100 inverter sends excess motor energy
into the resistor in the dynamic braking unit to slow the motor and load. If you have a
load that tries to drive the motor continuously for some period of time, that will require a
different type of inverter with continuous regenerative capability. As an example,
elevator control usually requires fast acceleration and deceleration profiles, so you may
need to add a dynamic braking unit. However, an application such as running an HVAC
fan may just coast to a stop in most cases.
The inverter parameters include acceleration and deceleration, which you can program to
match the needs of the application. For a particular inverter, motor, and load, there will
be a range of practically achievable accelerations and decelerations.