doble TDR9000, User Manual, Page: 279 / 454

TDR9000
™
Circuit Breaker Test System User’s Guide
72A-1898 Rev. A 11/01 A-79
Monday
, November 26, 2001 1:09 pm
Insertion Resistor
Value – Open
and Close Parameters include:
Open Resistor min The minimum allowable value for the Opening
Resistor in Ohms.
Open Resistor max The maximum allowable value for the Opening
Resistor in Ohms.
Close Resistor min The minimum allowable value for the Closing
Resistor in Ohms.
Close Resistor max The maximum allowable value for the Closing
Resistor in Ohms.
The TDR9000 measures resistance values from 10
Ω
to 7500
Ω
.
Res Tab Qualifier For tabulation, the Resistor Tabulation Qualifier sets the minimum
amount of time a resistor level (resistor switch closed and Main Contact
open) must be present for the
first touch to be considered the beginning
of the resistor level. The options are 200 Μ s, 100 Μ s, and bounce. If
200
Μ
s or 100
Μ
s are selected, the resistor level must be present during
the entire period specified (200 Μ s or 100 Μ s) without any transitions or
bounces for the first touch to be acceptable.
N
OTE
First touch is considered first strike for a close test and last break for an
open test.
Different values of resistor tabulation qualifiers are needed to
accommodate the characteristics of different circuit breakers. If the
characteristic of a circuit breaker is such that the resistor switch tends to
bounce extensively during operation, and the bouncing results in no
resistor switch
touching long enough to match the qualifier setting, then
the resistor switch is not seen by the test set, and the operating time of the
resistor switch is not tabulated. In such a case, the qualifier time can be
reduced from the default value of 200
Μ
s to 100
Μ
s to catch the resistor
switch (despite its bouncing) and obtain a tabulated value. This is
acceptable if the bouncing is a normal part of this particular circuit
breaker’s operation. If it is an abnormal phenomenon, however, reducing
the qualifier time to make the switch visible is self-defeating since the
tabulated value has no real meaning.
For purposes of determining a trend in a circuit breaker, and for
comparison among similar circuit breakers, use the largest time setting
which consistently yields a tabulated value for the resistor switch timing.