1–15

SJ300 Inverter

IntelligentFunctions and

Parameters

BrakingVelocity Profiles

Much of this manual is devoted to describing how to use inverter functions and how to configure inverter parameters. The inverter is microprocessor -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 particular 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 associated with motor deceleration, but may also occur even when the load attempts to drive the motor faster than the desired speed (overhauling). 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 certain SJ300 models) sends excess motor energy into a resistor to slow the motor and load (see “Introduction” on page 5–2 and “Dynamic Braking” on page 5–6 for more information). For loads that continuously overhaul the motor for extended periods of time, the SJ300 may not be suitable (contact your Hitachi distributor).

The inverter parameters include acceleration and deceleration, which you can set 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.

The SJ300 inverter is capable of sophisti-

 

 

 

 

 

cated speed control. A graphical representa-

 

 

Fixed speed

tion of that capability will help you

Speed

 

 

 

 

 

 

 

 

 

understand and configure the associated

 

Accel

Decel

parameters. This manual makes use of the

 

velocity profile graph used in industry

 

 

 

 

 

(shown at right). In the example, the acceler-

 

 

 

 

 

 

 

 

 

t

ation is a ramp to a set speed, and the decel-

 

 

 

 

 

Velocity Profile

eration is a decline to a stop.

 

 

 

 

 

 

Started Getting