Ground Fault Delay Test - GE MicroVersaTrip TVTS1 Manual

GROUND FAULT DELAY Test
Purpose
To provide an approximate indication that time delay oc-
curs wilhin the lime band selected. Because of the small
time magnitudes involved (often tenths of a second), the
timer's right digit provides only a rough approximation of
the actual trip time. If a more accurate reading is desired,
the EXTERNAL MONITOR jacks may be used. See page 20.
Description
The GROUND FAULT (GF) DELAY curve is a composite
curve consisting of an I't portion at the lower current values,
followed by fixed (MIN, INT, MAX) time delay bands at
higher current levels. Testing is accomplished
In
two sepa-
rate tests.
To provide protection against arcing ground faults, the
Micro-VersaTrip' programmer is equipped with a GF mem-
ory. It IS important, therefore,
In
runn'lng these delay tests to
allow a minimum of five seconds "off time" between each
individual energization of the programmer to allow the
memory to completely reset; otherwise, the time delay will
be low.
Before tests begin, it is necessary to determine whether
the programmer under test is equipped with ZONE SELEC-
TIVE INTERLOCKING. This can be determined by noting
whether there is a Z suffix in the catalog number on the
programmer face plate. Another method is to connect the
programmer to the test set and turn the TEST SELECTOR to
the GROUND FAULT-ZONE INTERLOCKED position. If the
ZONE INTERLOCKED light is lit, the function is present.
Test Procedure
TEST NO_ 1-1'1 CURVE
1. Set the programmer GF pickup setting to 0.2X.
2. Position Test Set controls:
PROGRAMMER TYPE-Set on:
TYPE A for: T4VT, TP4VT20, TP4VT25, T9VT,
TP9VT20, TP9VT25, TAVT20
TYPE B for TP4VT30, TP9VT30, TP9VT40, TAVT32,
TAVT40
Or determine by running CONVERTER CHECK
TEST SELECTOR-GROUND FAULT, STANDARD po-
sition.
3 TEST CURRENT -Preset one of the test current values
shown In Table 7A.
4. Reset timer and push RESET button.
5. Push START -A trip light must be obtained. Observe
trip time. For 50-Hz operation, multiply the timer reading
by 1.2.
6. Allow five seconds "off-t'lme" for the GF memory to
reset.
7. Repeat using the other test current values in Table 7A,
allOWing five seconds "off-time" between tests
16
TEST NO.2-FIXED TIME DELAY
1. Set the programmer GF pickup setting to 0.2X.
2 Position Test Set controls-Same as Test NO.1.
3. TEST CURRENT-Preset a reading of 1.000
4. Reset timer and push RESET button.
5. Push START. A trip light must be obtained. Observe
trip time.
NOTE: It is important to observe that the time
delay will be dependent on whether or not the
programmer being tested is equipped with ZONE
SELECTIVE INTERLOCKING. Select the proper
Table (78 or 7C).
Repeat Steps 4 and 5 for each GF DELAY (MIN, INT, MAX),
allOWing five seconds "off-time" between tests for the GF
memo ry to reset.
6. If the programmer is equipped with the ZONE SELEC-
TIVE INTERLOCK option, continue by testing as follows
a. Position the TEST SELECTOR In the GF ZONE IN-
TERLOCKED position.
b. Repeat Steps 4 and 5 for each GF DELAY (MIN, INT,
MAX)
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