I.L. 32-693 A
Page 7
Effective September 1998
10. Push
TEST button. TIMER will give an approximate
reading of the delay.
Note: This is not accurate enough
for close timing of short delay but, it will show the
difference between the band calibrations.
11. Remove the Zone Interlock Defeat adapter, and repeat
the test. Time delay should read minimal.
4.9 CHECKING GROUND PICKUP (IF TRIP UNIT IS SO
EQUIPPED)
1.
Set desired Ground Fault Pickup on Trip Unit.
2.
Set the Test Kit as follows:
2A.
HI-LO AMPS switch to “LO AMPS”.
2B.
CURRENT ADJUSTMENT to “ZERO”.
2C.
TIMER to “OFF”.
3.
Push
RESET button.
4.
Hold
GROUND TEST momentary switch in down
position during steps 5 and 6.
5.
Push
TEST button.
6.
Increase
CURRENT ADJUSTMENT slowly until the
breaker trips.
7.
Prior to returning
CURRENT ADJUSTMENT to “ZERO”,
hold
GROUND TEST switch in the down position and
CALIB switch in “CALIB” position to read the trip
current.
8.
For pickup values see Table 1 below.
Note that the
pickup values shown on the Test Kit are in secondary
amperes. To convert the Test Kit reading to primary
values, multiply ammeter readings by I
n
/ 5.
(1) Examples:
(a) Assume I
t
= 1.2amps, I
n
= 200, pickup setting =
.25, then: I
g
= 1.2 x 200/5 = 48 primary amperes.
Table 1 shows expected value of 1.25 amperes. 1.2
amperes is within the + 10% tolerance.
For reference purposes, Table 2 shows primary
Ground Fault amperes
Note: Expect increased pickup currents due to the
required sensor exciting current.
4.8 CHECKING SHORT DELAY TIME (IF APPLICABLE)
Note: Zone Selective Interlocking essentially disables
Short Delay Time. This function is provided as a
standard feature on all Magnum Trip Units. To test the
Short Delay Time when the breaker is removed
beyond the test position in the switchgear, the zone
interlock shorting plug must be utilized (
see Figure 5
).
Without this, all Short Delay Time values will be
minimum.
1.
Dial Short Delay and Long Delay Pickup on Trip Unit as
desired.
Note: 2.5 times the short delay pickup setting
should not exceed the capability of the Test Kit
(approx. 50 amperes). i.e. Maximum short delay
pickup (I
r
)= 4. Note that the Short Delay Pickup (I
r
) is
a function of the Long Delay Setting times the Short
Delay Pickup setting.
2.
Set
Long Delay Time to maximum, and Instantaneous
“off”, so that these functions do not trip the breaker.
3.
If the breaker secondary contacts are not connected to
the switchgear Zone Interlock wiring (breaker is
beyond the test position), install the Zone Interlock
Defeat adapter.
4.
Set the Test Kit as follows;
4A.
TIMER switch to “OFF”.
4B.
HI-LO AMPS switch to “HI AMPS”.
4C.
CURRENT ADJUSTMENT to “ZERO”.
5.
Toggle the
CALIB switch to “CALIB” position and adjust
current, using
CURRENT ADJUSTMENT knob, to 2.5
times pickup setting. Note that if the breaker is closed,
it will trip. Do not reclose the breaker until the test
current is adjusted to the proper value.
6.
Reset Trip Unit by pressing the “trip reset” pushbutton
on the Trip Unit.
7.
Close the breaker.
8.
Turn
TIMER “ON”. If TIMER does not read zero, push
RESET (Timer) button.
9.
Push
RESET button.
