Vanguard CT-7000 - Manual (Page 8)

CT-7000 Operating Instructions
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1.0 Introduction
The CT-7000 is a microprocessor-based, digital time travel, circuit breaker analyzer. The CT-
7000 can fully analyze a utility circuit breaker’s performance by measuring: the contact time,
stroke, velocity, over-travel, bounce-back and contact wipe.
The contact motion analysis includes: Open, Close, Open-Close, Close-Open and Open-
Close-Open operations. A timing window is selectable between one second, ten second and
twenty second periods. The ten and twenty second windows allow timing of long events such as
circuit switcher contacts.
The CT-7000 is available with the following configurations:
CT-7000-3:
n Three Contact-Input channels
n Three Digital Travel Transducer Input channels
n One Analog Voltage Monitor Input channel
n One Digital Voltage Monitor Input channel
n One Trip/Close Current Monitor channel
CT-7000-6:
n Six Contact-Input channels
n Three Digital Travel Transducer Input channels
n One Analog Voltage Monitor Input channel
n One Digital Voltage Monitor Input channel
n One Trip/Close Current Monitor channel
CT-7000-12:
n Twelve Contact-Input channels
n Three Digital Travel Transducer Input channels
n One Analog Voltage Monitor Input channel
n One Digital Voltage Monitor Input channel
n One Trip/Close Current Monitor channel
There are two different modes of operation for the CT-7000 which are Stand Alone Mode and
Computer Control Mode. The manual will focus on the Stand Alone Mode. The Computer Control
Mode is covered under the CT-6500/7000/7500/DIGITMR PC software manual.
2.0 CT-7000 Description
The CT-7000 applies a test voltage of 35 Vdc to each of the contact channels thus allowing an
analog to digital converter (A/D) to determine if a close, an open or an insertion resistor was the
state of contact. The CT-7000 records into the memory 10,000 readings from the A/Ds and the
transducer position counters. The contact time, circuit breaker stroke and velocity is then derived
from the data that was stored in the memory.
The CT-7000 uses an up-down counter to sense the breaker’s transducer reading. The CT-
7000 travel transducer employs optical encoders to send quadrature signals to the CT-7000’s
counters. With the use of digital transducers and counters, the need to set up or calibrate the
transducers is eliminated.
A built-in, initiate circuit allows the user to operate the circuit breakers. Since the solid-state
circuit is controlled by a microprocessor, the CT-7000 can perform multiple contact operations
with ease. The initiate circuit is fuse protected for trip and close operations. The user is required
to hold the “ARM” switch during a test to complete the initiate circuit as a safety feature.