Vanguard CT-7500 User Manual
Page 10
MODEL CT-7500
OPERATING INSTRUCTIONS
4
Rev 2 Jan 2001
2.2.13 CT-7500 Display and Control Switches
An alpha-numeric keypad lets the user enter breaker’s name plate data (Substation name,
Breaker Model, etc) and control function. A 4-line by 20-character LCD readout displays user
messages. The LCD is back lighted so messages can be viewed in low light levels.
3.0 Test Result Tabulation
3.1 Electrical Measurement Results
Each CT-7500 contact channel provides the following test results:
Contact Close time, (Quick-Shot) Mode.
Contact Open (Clear) time, (Quick-Shot) Mode.
Main contact and insertion resistor contact times (Time-Travel Test).
Contact bounce time (Time-Travel Test).
Contact spread time (Time-Travel Test).
NOTE
The CT-7500 can detect insertion resistors in a 10-7000 ohm range. Resistances over 7000
ohms are detected as an open contact.
3.2 Mechanical Measurement Results
Each digital transducer channel provides the following test results:
Breaker stroke (Time-Travel Test).
Over travel (Time-Travel Test).
Bounce back (Time-Travel Test).
Contact wipe (Time-Travel Test).
Velocity (Time-Travel Test).
Breaker contact speed calculation is based on a contact's travel distance over a period of time,
which is defined by the manufacturer's specifications.
A CT-7500 not only calculates simple distance-over-time speeds, but can also support other
formulas. An example is Siemen TCP breaker calculation formula:
V=12.2 x a/b
The formula and analysis points can be stored in a test plan for use later in the field.
NOTE
If operators use a breaker test plan (see paragraph 9.8) during testing, the test report will also
indicate a Pass/Fail condition for each test parameter (i.e. contact time, stroke, velocity, etc.).
3.3 Analog Voltage Input Results
The analog voltage input channel (V1) measures the breaker's dc control voltage during
operation. Printed voltage readings include nominal voltage (supply voltage at no load) and
minimum voltage (supply voltage under load or when a coil is energized).
This connection allows the user to monitor the DC power supply voltage fluctuation during
breaker’s operation. This feature is handy to detect breaker’s power supply problem; which