DDA-1600
Circuit Breaker Test Set
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Model DDA-1 Digital Data Acquisition
Instrumentation and Control System
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Variable pulse time and firing-angle
output current control
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Tests wide range of breakers
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Modular, portable design
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Compliant with NEMA AB-4 test
guidelines
DDA-1600
Circuit Breaker Test Set
DESCRIPTION
The Model DDA-1600 Circuit Breaker Test Set incorporates
proven transformer design with the latest development in
high-current instrumentation and control. This new design
means the DDA-1600 is fully compliant with NEMA AB-4
test guidelines.
This combination provides the user with a portable,
economical, high-current source for primary injection
testing.
Model DDA-1600 provides all the controls, instrumentation
and output capabilities to test low-voltage circuit breakers
in a three-module configuration.
Module 1 – Controller and instrumentation module
contains all the control circuitry and instrumentation
needed for manually testing low-voltage circuit breakers.
Module 2 – Power module contains the coarse and finecurrent controls, along with the SCR initiate package.
Module 3 – Output module contains the high-current
output transformer and the current sensors.
Model DDA-1600 comes complete with all interconnect
cables. Each module is housed in its own rugged, compact
enclosure. The test set is easily transported and may be
connected to the test device by cables or stab assemblies.
APPLICATIONS
Ideally suited for industrial, utility and testing service
company use, Model DDA-1600 is designed to maintain
and test low-voltage power circuit breakers rated to 1600ampere frame size.
In addition, it can be used for verifying the ratio of current
transformers and testing thermal or magnetic motor
overload relays.
In the series configuration, the higher voltage output of
Model DDA-1600 permits ready use in substations for
primary injection testing of high-voltage circuit breakers
and protective relays.
FEATURES AND BENEFITS
Model DDA-1600
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Portable: Housed in a lightweight, rugged, three-piece
chassis that can be carried. This reduces the need for
heavy equipment to transport the test set.
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Versatile: Designed to test a wide range of air frame and
molded-case circuit breakers. Model DDA-1600 will test
airframe circuit breakers rated up to 1600 amperes and
molded-case circuit breakers rated up to 1200 amperes.
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Initiating control circuit: Fully digital initiating
control circuit provides both pulsed and maintained
control modes of output duration.
The pulsed mode automatically pulses the output to any
programmed pulse duration. This provides additional
testing capabilities for electromechanical and solid-state
trip devices. A short pulse duration also limits the
preheating of the breaker under test while setting the
test current.
In the maintained mode, the output remains energized
until the device under test operates, which both stops
the timer and de-energizes the output.
DDA-1600
Circuit Breaker Test Set
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Zero dc offset: Use of digitally controlled SCRs instead
of a contactor to initiate the output of the test set
eliminates closing-time error and ensures precise
initiation at of the output current waveform every time.
Accurate, repeatable test results are ensured even with
currents of very short duration, as when conducting tests
of instantaneous or short-time delay trip elements.
The digital control of the SCRs also allows the unit to
initiate at any point within 90 degrees of the zero
crossover point of the output-current waveform. This will
allow the elimination of a the dc offset caused by a
change in impedance of the varying loads.
Controller and Instrumentation
Module
Model DDA-1: The Digital Data Acquisition
Instrumentation and Control system was designed
specifically to provide precise control of the output current
and accurate metering of the breaker under test. Model
DDA-1 uses the latest in Digital Signal Processing (DSP)
technology. This technology provides complete digital
control of the SCRs and digitally samples the output
current for high-accuracy measurements.
Digital ammeter: Model DDA-1 samples the output
current digitally and mathematically calculates the current
that is supplied to the breaker under test.
This process increases the accuracy of the ammeter
systems and provides extreme flexibility in what current
value is displayed. For example, when the test set is
delivering a continuous current, the digital ammeter is
continuously sampling the output waveform and can
therefore display a true rms value of the current.
For measuring short-duration currents, Model DDA-1 can
calculate the output current in the following ways via
selection from the soft control buttons on the panel:
1.For any output current greater than one cycle, Model
DDA-1 can calculate the true rms value of the output
current pulse. For any output less than one cycle, a true
rms measurement is invalid.
2.For any current pulse, Model DDA-1 can measure the
peak current and calculate an anticipated rms value of
the current from the peak current.
This multiple-current calculation feature is also useful
when testing different styles of solid-state trip devices. This
feature allows the test set to simulate a similar type of
current calculation that is being used by the various solidstate trip devices.
Digital timer: Because of the Model DDA-1 digital signal
processing technology, the system knows exactly when
current is present and when the breaker under test opens.
This provides a high-accuracy timing even when testing
the instantaneous trip function on fast-acting breakers. The
digital timer can display the breaker trip time in cycles or
seconds.
A completely digital, solid-state circuit automatically starts
the timer when the output current starts to flow and stops
it when the device under test operates. This circuit will
accommodate a variety of test conditions including:
1.When testing a circuit breaker or a device which has no
auxiliary contact to monitor (each as a single-pole circuit
breaker), the timer starts when the output current starts
to flow and stops when the output current is
interrupted.
2.When testing a device and monitoring normally closed
contacts, the timer starts when the output current starts
to flow and stops when the contacts open.
3.When testing a device and monitoring normally open
contacts, the timer starts when the output current starts
to flow and stops when the contacts close.
Digital voltmeter: Model DDA-1 can be used to
measure the input voltage to the test set or the output
voltage from the test set. It also can be used as a diagnostic
tool to evaluate contact condition by measuring the voltage
drop across breaker contacts while subject to high current.
Panel indicators: Panel lamps incorporated for operator
safety and convenience, indicate:
1. Output of the set ENERGIZED
2. Thermal WARNING or SHUTDOWN
3. GROUND INTERLOCK open
4. OVER RANGE of ammeter
External initiate circuit: allows initiation of the test set
from a remote location when desired.
Model DDA-1600 uses the Model DDA-1 Digital Data Acquisition Instrumentation and Control System. This system offers the latest in digital signal
processing technology to control the test set and measure reactions of the breaker under test.
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