Yaskawa VCD 723 - Manual (Page 9)

1 Introduction
3 Drive Description
9/15/93
Drive
Description
The MicroTrac name is used to describe MagneTek's family of digital system
drives and the compatible products used to create systems. This manual
describes the MicroTrac compatible VCD 723 AC motor drive.
The VCD 723 is a high performance, sine-coded, Pulse Width Modulated
(PWM) AC motor drive which generates an adjustable three phase output for
complete speed or torque control of a compatible AC induction motor. The
VCD 723 can maintain a 150% current overload for 60 seconds with automatic
stall prevention and voltage boost to prevent nuisance tripping during load or line
side transient conditions. The VCD 723 will not induce any voltage line
notching distortion to the utility line and maintains a displacement power factor
of approximately 0.98 throughout its speed range.
The VCD 723 drive is totally software configurable to the application through a
high level graphical language, called Programmable Application Control (PAC).
PAC provides complete flexibility without having to make hardware
adjustments. Interface to other equipment is provided with local Input/Output
(I/O) or a high speed Local Area Network (LAN). Use of the LAN means that a
single coaxial cable eliminates multiple conductor cables and provides high
noise immunity. Extensive diagnostic and setup capability are provided through
two control/display units. The Local Control/Display Unit (LCDU) is mounted
flush with the drive cover and consists of a Liquid Crystal Display (LCD) with
two lines of sixteen alphanumeric characters, five pushbuttons, and five status
Light Emitting Diodes (LED’s). The LCDU can be used for all setup functions
and many diagnostics. The Portable Control/Display Unit (PCDU) is an optional
hand-held device that can be plugged into any MicroTrac compatible drive and
used for all the same functions as the LCDU plus some advanced diagnostics.
The PCDU has two lines of sixteen alphanumeric characters and a thirty-key
keypad.
The distributed control architecture of the MicroTrac system means that each
drive performs its own regulation calculations synchronized to a common high
accuracy crystal master. Thus, even minute crystal drift will not affect multiple
drive tracking. This allows a MicroTrac system to maintain the drift between
sections to 0.00% at steady state. The fully digital nature of the regulation
means that an individual drive can maintain a 0.00% average difference between
set and actual speed from no-load to full-load when using digital tachometer
speed feedback. Digital setup and performance assure exact process line and
finished product duplication shift to shift and month to month. Speeds, tensions,
ratios, draws, limits, ranges, alarms, and other control parameters can be set as
percentages or exact numerical values via keypad or thumbwheel switches with
up to six digits of resolution. Parameters are entered and displayed in plain and
understandable English. The drive can be completely set up prior to actual
running and changes can be made during operation. Keypad entry of changed
parameters, protected memory, and factory default values allow the operator to
modify data with minimum risk to the process.
Performance
Flexibility
Accuracy