Functional Overview - Parker 690+ Series Product Manual

2-6
An Overview of the Drive

Functional Overview

690+ AC Drives are microprocessor based 3-phase drives 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 Keypad allows access to various options and
adjustable parameters.
The diagram above shows the basic internal arrangement of the drive with the circuitry split
between the control circuits, and the power circuits.
Power Circuits
IMPORTANT: An external AC Line Choke is required for each drive, between the supply and L1, L2, L3.
Refer to Chapter 8: "Technical Specifications" - AC Line Choke.
The 3-phase supply is connected to terminals L1, L2 and L3, and is rectified to produce the DC
link.
Dynamic Braking
The in-line choke and DC link capacitors, smooth the DC link voltage. 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, each
drive must be fitted with an identical drive brake unit. An external brake resistor is switched to
be in parallel with the DC link 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: Drive Brake Unit for
details of the dynamic braking option.
CONTROL
INPUTS &
OUTPUTS
L1
3 PHASE
INPUT
INPUT
3 PHASE L2
BRIDGE
SUPPLY
(3% LINE
L3
IMPEDANCE
REQUIRED)
PE
SUPPLY
EARTH
PE
MOTOR
EARTH
Figure 2-3 Functional Block Diagram
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KEYPAD
CONTROL CIRCUITS
& SOFTWARE
DC+
DC-
Master drive only
MASTER
POWER
BOARD
SLAVE
POWER
BOARD
M1/U
INVERTER
M2/V
CIRCUITS
M3/W
DC+
DBR
DYNAMIC
BRAKE
UNIT
DC-
690+ Series AC Drive
MOTOR
DRIVE
OUTPUTS
EXTERNAL
BRAKE
RESISTOR