Atec 3091LD User Manual
California Instruments 3091LD
3000–12000 VA
3000VA Programmable AC Loads
• Multi-mode AC Electronic Load
Flexible solution for a wide range of AC power test
applications
• 3000 Watt Power Dissipation
Master / Auxiliary congurations for higher power
and multi phase applications
• 50 to 350 V, 45 Hz to 440 Hz
Commercial, Military and Avionics applications
• Programmable Crest & Power Factor
Test AC power products for real-world conditions
• Built-in Measurements
Eliminates the need for additional test equipment
in bench or ATE applications
• Remote Control
IEEE-488 and RS232C Interface for automated
test applications
AC Loads
The 3091LD is designed to provide precisely
controlled, non-linear loads for testing AC power
generation equipment such as UPS’s and AC
sources. In addition, any active or passive current
carrying devices such as switches, circuit breakers,
fuses, connectors and power semiconductors
can be tested. Traditionally, many of these
products are tested using resistive load banks.
This approach does not simulate real-world
conditions such as switching DC/AC converters
found in many AC powered products. This type
of conventional testing does not fully exercise
the equipment under test (EUT) under worst case
operating conditions. High peak currents and low
power factor loads can signicantly impact the
operating characteristics of a UPS or AC power
product. The 3091LD AC Load can simulate
high crest factor and variable power factor load
conditions. This provides an effective method of
testing AC products against real-world conditions
and can signicantly increase product reliability.
Unless properly exercised, product defects may go
undetected until a unit is used at a customer site,
resulting in costly eld returns.
Front Panel Control
The AC load can be operated from an easy to
use, menu driven front panel. Product tests
can be performed quickly in an R&D setting by
punching up specic load conditions on the front
panel and reading the measurement screen of
the 3091LD. This fast interactive front panel
control mode can be used during a product’s
early development cycle to isolate potential
performance problems before the product leaves
the engineering lab.
Automated Testing
The 3091LD can be deployed in ATE test stations
using either IEEE-488 or RS232C remote control.
The industry standard SCPI (Standard Commands
for Programmable Instrumentation) protocol
is used and instrument drivers are available to
ease test software development. The built-in
metering functions of the 3091LD AC load can
be used to eliminate the need for additional test
equipment such as meters, power analyzers and
oscilloscopes.
This and the reduced size of the 3091LD
compared to passive load banks, represents a
savings in both cost and rack space.
Power Levels
Each 3091LD is capable of dissipating 3000 W
of single phase AC power. For higher power
or three phase applications, a 3091LD master
unit can be combined with one or more auxiliary
3091 units. The master 3091LD unit provides the
required consolidated measurements so the test
system controller - or the operator - need only
interface to the master unit, regardless of the
specic conguration. Single, split or three phase
congurations can be software congured from
the master 3091LD when combined with 3091
slave units.
User Control
All AC load modes are easily set from the front
panel using a menu-driven user interface.
The large LCD screen is used to display setup
information as well as measurement data.
Measurements include volt RMS, volt peak,
current RMS, current peak, crest factor, true
power, apparent power, power factor and
frequency. Both voltage and current waveforms
at the load input terminals can be digitized
and displayed on the front panel graphical
LCD. This allows EUT output behavior to be
50–350 VRMS
30 ARMS
AMETEK
Programmable Power
9250 Brown Deer Road
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3091LD
analyzed quickly without the need to hook up
additional test equipment. A Windows graphical
user interface (GUI) is provided to expand the
measurement and display capabilities of the
3091LD. The GUI can be used to save and print
test results for report purposes.
Crest Factor and Power Factor control
When operating in constant current or constant
power mode, the 3091LD supports crest factor
control by narrowing the conduction angle of
the current waveform in order to match the
requested crest factor. Thus, the peak current is
increased while retaining the RMS current level.
While the apparent power remains constant, the
true power decreases. This results in a reduced
true power factor. Consequently, as crest factor
is increased, the true power factor automatically
decreases. The load further controls power
factor by shifting the current with respect to
the input voltage (displacement power factor).
Both leading and lagging power factor control
is available. A phase shift of the current is only
possible if the crest factor is higher than 1.414.
Thus, crest factor and power factor control ranges
are coupled as shown in the graph to the right.
Front Panel
The large LCD screen is used to display setup
information as well as measurement data.
Measurements include volt RMS, volt peak,
current RMS, current peak, crest factor, true
power, apparent power, power factor and
frequency. Both voltage and current waveforms
at the load input terminals can be digitized
and displayed on the front panel graphical
LCD. This allows EUT output behavior to be
analyzed quickly without the need to hook up
additional test equipment. A Windows graphical
user interface (GUI) is provided to expand the
measurement and display capabilities of the
3091LD. The ICS can be used to save and print
test results for report purposes.
Power & Crest Factor Control Range
Load Power Rating curve for 3091LD
The 3091LD can be used to emulate a wide variety of
AC load conditions to support real-world testing and
evaluation of UPS and AC source products. Specically,
the following modes can be selected:
Mode Description
Constant
Power
Constant
Resistance
Constant
Current
Constant
Voltage
Short
circuit
CP This mode effectively emulates constant
power loads such as switching power
supplies
CR Emulates a conventional resistive load or
power resistor. A programmable range
from 2.5 Ohms to 1000 Ohms covers a
wide range of applications. This mode
can be used to replace conventional
resistive load banks.
CC Provides a constant current load. This
mode may be used to simulate both linear
(resistive) and non-linear (active loads for
voltage regulation testing.
CV This mode emulates a shunt regulator
load and may be used to test current
source products.
SC Test the short circuit protection mode of
the EUT by providing a short condition.
The 3001LD can handle surge currents
of up to 300 Amps for up to 50 msec and
sustained currents of 30 Amps in this
mode of operation. The low voltage
cut-off of the load can be programmed
from 50 Volts up.
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