Ratings - GE NBVllA Series Instructions Manual

The negative-sequence voltage will be proportional to the unbalance in the line
voltages. When
connected to the relay studs 5,
across the relay coil, TR, which is proportional to the negative-sequence voltage,
will be zero. When the voltages supplied to the relay are unbalanced in either of
the two possible ways,
relay coil will be proportional to the voltage unbalance,
section on CALCULATIONS.
balanced voltage.
It should be noted that other non-motor load connected to the bus will in most
cases tend to increase the unbalance in the voltages.
detect a single-phase condition with only motors on the system, then any additional
non-motor load, such
positive or leave it unchanged.
To avoid confusion
voltage, V R , as the single-phase voltage that, when connected to the relay as shown
in Figure 10, will just cause the relay to pick up.
volts for the 120 volt relay and between 17 and 34 volts for the 208 volt relay.
The corresponding negative phase-sequence voltages are 5.8 - 11.5 for the 120 volt
relay and 10 - 20 for the 208 volt relay.
The operating characteristics are shown in Figures 4 and 5.
time to open the normally-closed contact, and the time to close the normally-open
contact, as functions of multiples of pickup.
return the contacts
removed, is shown in Figure 5.
RELAY MODEL
12NBV11A1 A
12NBV11A2A
12NBV11A3A
12NBV11A4A
12NBV11A5A
12NBV11A7A
The relay will withstand rated voltage continuously with normal phase sequence and
for 60 minutes with reverse phase sequence.
rated voltage continuously.
Contacts
The telephone-type relay contact ratings are shown in Table I.
a balanced three-phase
6 and 7, as shown in Figure 8,
as illustrated in Figure 9,
On reverse phase voltages, the relay will pick up even on
as lighting,
and to facilitate
to their normal
RATED VOLTAGE RATED FREQUENCY
120
120
208
240
208
216
GEI-50261
voltage of
then the voltage across the
Thus, if the relay is set to
will either make
tests, we shall
This will be between 10 and 20
The dropout time,
positions when the

RATINGS

PICKUP VOLTS, MIN.-MAX.(±10%)
60 Hz
50 Hz
60 Hz
60 Hz
50 Hz
60 Hz
The relay will withstand single-phase
4
correct phase sequence
then the voltage
as demonstrated in the
the relay's operation
define the relay
Figure 4 shows the
or the time to
unbalanced voltage
10-20
10-20
17-34
20-40
17-34
17-34
is
more
pickup
�,
is