Ratings; Characteristics; Operating Principles - GE IJS52D Instructions Manual

6EI-90802
On systems where lines mayor may not be tied together elsewhere, the IJS relay is
used in para" el with the Type GES relay to permit closure of a breaker with zero
frequency difference.
Depending on the external connections used (see Figure 9), the telephone relays "B"
and "L", mentioned above, serve to reclose the breaker under conditions of (1) dead
bus or line, (2) live bus, dead line, (3) dead bus, live line, (4) dead bus, live
line, or live bus, dead line (5) dead line, bus live or dead (6) dead bus, line live
or dead.
RATINGS
The operating and restraining coils of the synchronism-check unit are continuously
rated. The contact of this unit will make and carry momentarily 30 amperes, but it
has no interrupting rating.
The telephone-type voltage relay contacts will make and carry 30 amperes momentarily
for normaly duty, but the circuit must be opened by a breaker auxiliary unit or
other suitable means.
The telephone-type relays have operation coils rated at either 67 or 115 volts.
CHARACTERISTICS
OPERATING PRINCIPLES
The operating coils, mounted on the left-hand side, produce a torque tending to
close the synchronism-check contact. This torque is proportional to the vector sum
of the vol tages whose phase positions are being compared. The torque produced by
the restraint coils is proportional to the vector difference of the voltages. The
operating torque is maximum when they are in phase; the reverse is true of the
restraining torque.
The closing angle of the relay is defined as the maximum phase displacement of the
two voltages at which the relay will close its synchronism-check contact when the
voltages are at rated value. The 20
0
closing angle is considered standard; however,
other settings may be made, as indicated by the voltage-phase angle characteristics
s h
0
wn i n Fig u re 1.
The time-delay characteristics of the Type IJS relay are obtained primarily by the
time-dial setting. The time dial controls the distance the contacts must travel
before closure, and hence controls the time delay. At No. 10 time-dial setting, the
travel is maximum, whereas at No. 0 the contacts are just closed. A certain amount
of adjustment may be made by changing the position of the drag magnet on its shelf.
Moving it toward the disk shaft decreases the time delay, while moving
it
away from
the disk shaft increases the time delay.
Typical time vs. phase-angle curves are shown in Figures 4 and 5 for 60 cycle
relays. The Model 12IJS52Dl relay has a standard closing angle setting of 20
0 ,
and
has its drag magnet adjusted to provide 20 seconds time delay from the No. 10 time-
dial setting for voltages in phase. The closing angle on this relay can be adjusted
to angles greater than 20
0 ,
but with a corresponding decrease in time delay, as
4