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Megger
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DDA-3000
and
DDA-6000
Universal Circuit Breaker Test
Sets
DDA-3000
and
DDA-6000
Universal
Circuit
Breaker
Test Sets
DESCRIPTION
Incorporating
the
latest technological advancements,
Models
DDA-3000
and
DDA-6000 Series are designed
specifically
to
test low-voltage
power
and
molded-case
circuit breakers
equipped
with thermal, magnetic
or
solid-state trip devices.
The
units are fully compliant
with
NEMA
AB-4 test guidelines.
Tests are
performed
by
simulating
an
overload
or
fault
condition. Each test
set
is
an
integrated test system that
provides a variable, high-current output. The test sets
incorporate all control circuitry
and
instrumentation
necessary
to
test direct-acting circuit breakers accurately,
efficiently
and
safely.
The unique transformer
and
circuit design results in a very
high-capacity test set in a very compact size. Advanced
digital
control
and
instrumentation provides exact testing capacity.
APPLICATIONS
Universal
in
application,
the
test sets will test virtually
all low-voltage, molded-case
and
metal-clad, direct-acting
ac circuit breakers
produced
by
General Electric,
Westinghouse, Federal Pacific, Square D, Gould,
ABB,
ITE,
Siemens
and
other
manufacturers.
Model
DDA-3000 is rated for testing breakers
up
to
3000 amperes. Model DDA-6000
is
rated for testing
breakers
up
to 6000 amperes. Rugged
and
reliable,
Megger circuit
breaker
test sets will provide years
of
trouble-free operation.
The test sets also
may
be
used
for other high-current
applications,
such
as verifying
the
ratio
of
current
•
Model
DDA-1
Digital
Data
Acquisition
Instrumentation
and
Control
System
•
High-current
output:
60,000
A
for
Model
DDA-6000;
35,000
A
for
Model
DDA-3000
•
Digital
signal processing (DSP)
technology
•
Variable
pulse
time
and
firing
angle
output
current
control
•
Compliant
with
NEMA
AB-4
test
guidelines
transformers
and
performing
heat
runs
or
primary injection
testing
of
high-voltage breakers
and
their associated
protective relays.
All
Model DDA-3000
and
DDA-6000 test sets have identical
features, instrumentation
and
operational characteristics.
The
only changes
in
the specifications
among
the
units are
their size, weight
and
maximum output-current capacity.
FEATURES
AND
BENEFITS
III 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 manually
turned
off or, during timing test, until the
device
under
test operates,
which
both
stops
the
timer
and
de-energizes the output.
II
Zero
de
offset:
Use
of
digitally controlled
SCRs
instead
of
a contactor
to
initiate
the
output
of
the
test
set
eliminates closing-time error
and
thereby
ensures precise
initiation at
the
zero crossover
point
of
the
output
current waveform every time. Initiation at
the
zero
crossover
point
ensures symmetrical
output
current
by
eliminating
dc
offset in
the
current waveform. Therefore
accurate, repeatable test results
are
assured
even
with
currents
of
very short duration, as
when
conducting tests
of
instantaneous
or
short-time delay trip elements.
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