Hitachi SJ100 Series Instruction Manual page 36

1–10
Introduction to Variable-Frequency Drives
Intelligent Functions and Parameters
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.
Braking
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 a
braking resistor. The dynamic braking unit (built into the SJ100) sends excess motor
energy into the resistor to slow the motor and load (see pages 5–2 and 5–5 for more
information). 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 deceler-
ation profiles, so you may need to add a braking resistor. 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.