Eurotherm Drives 584S, Product Manual, Page: 24 / 176

Chapter 2 - PRE-INSTALLATION PLANNING
584S Frequency Inverter 2-1
Chapter 2 PRE-INSTALLATION PLANNING
FUNCTIONAL OVERVIEW
Principles of Operation
584S Frequency Inverters are microprocessor based 3-phase inverters used to control the speed of standard 3-
phase induction motors. An extensive range of configuration options are available to the user. A menu structure
controlled using the man-machine interface (MMI) allows access to various options and adjustable parameters.
A simplified block diagram of a 584S is presented in Figure 2.1. This shows the basic internal arrangement of
the drive with the circuitry split between the control circuits, and the power circuits. The functions of the control
circuits are further expanded in Figure 2.2.
Power Circuits Power Circuits Power Circuits Power Circuits
The 3-phase supply is input on terminals L1, L2 and L3 and is rectified to give a DC output to the inverter
circuits. The connection between the rectifier and inverter is called the DC link and comprises a positive and
negative DC connection with an in-line choke.
Dynamic Braking Dynamic Braking Dynamic Braking Dynamic Braking
The in-line choke and DC link capacitors, smooth the DC voltage prior to input to the inverter power stage.
During motor deceleration or at other times when the motor acts as a generator, energy flows from the motor into
the DC link capacitors and causes the DC link voltage to rise. The drive trips if the DC link voltage rises above
the over voltage trip level. If the dynamic braking option is used, an external brake resistor is switched to be in
parallel with the capacitors and absorbs the energy when the DC link voltage rises to the braking level. Voltage
detection is performed by the control circuits and the switching is performed by the optional dynamic brake
circuit. Refer to Chapter 3 for further details of the dynamic braking option.
Motor Drive Output Motor Drive Output Motor Drive Output Motor Drive Output
The inverter circuits convert the DC input to the 3 phase output used to drive the motor. The GATE DRIVE
signals generated by the control circuits control the inverter circuits to reproduce the 3-phase MOTOR DRIVE
OUTPUTS. The frequency and amplitude are determined by the control inputs and by the parameters set up via
the MMI.
Control Circuits and Software
Control Circuits and Software Control Circuits and Software
Control Circuits and Software
The control circuits and software block in Figure 2.1 are expanded in the functional block diagram Figure 2.2.
This diagram shows software configuration options. It is not representative of the hardware since most of the
functions are performed entirely by software.
Inputs to the control circuit are provided by physical connections to the control board terminals (identified on the
left and right hand edges of the block diagram) and by parameters set via the MMI display (as explained in the
"KEY" of Figure 2.2).
Parameters
Parameters Parameters
Parameters
Parameters are values or options that are programmed via the Setup Parameters and System menus within the
MMI structure. These are usually set up during installation and commissioning and are not changed during
normal operation.
Number parameters assign a value to a variable, eg. PRESET SPEED 1 which determines the motor speed if
PRESET SPEED 1
is selected.
Logic parameters are used to control switching functions, eg.
AUTO SETPOINT SELECT
which controls a
software switch to select one of a number of sources of the auto setpoint.
Refer to Chapter 4 for further information on the MMI and parameter descriptions.
Diagnostics Diagnostics Diagnostics Diagnostics
Number and logic diagnostics are values and settings that can be displayed via the diagnostic menu within the
MMI. These values are read-only and are provided for the user to determine operating or fault conditions. Refer
to Chapter 5 for further information and descriptions of the diagnostics.
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