GE IAV51A Instructions Manual page 9

(
(A)
For Flush Mounting
(B)
For
tacts close. Hence, simultaneous adjustments for
closing left and closing right must be made to obtain
a desired characteristic.
Time Setting
The time of operation of the
IA V54A,
and the
by the setting of the time dial, while that for the
IA V53A
is determined by the spread of the contacts
as explained under "voltage setting." Further ad­
justment is obtained by moving the permanent
magnet along its supporting shelf; moving t he mag­
in
net toward the back of the relay decreases the
time while moving it out increases the time.
2
Fig. shows the time-voltage characteristics of
IAVSlA
the and the
for obtaining each characteristic. To make time
settings, set the time dial to the number required
(to give the desired characteristic) by turning it
until the number lines up with the notch in the
adjacent frame. The time indicated by the curves is
the time required to close the relay contacts when
Surface
Mounting
6.
Fig. Outline and panel drilling for relay Type IAV53A
IA VSlA, IA V52A,
IA VSSA
is determined pt imarily
IAV52A
with the dial setting
Type IAV Undervoltage and Overvoltage Relays
Panel Opening
Front
Panel Drilling
Front
the voltage is suddenly increased from a value below
pickup to the value on the curve.
Time settings on the
are quite similar except that their characteristics, as
shown in Fig. 4, indicate the time required to close
the contacts when voltage is suddenly reduced from
operating value or above, to the values on the
cmves.
3
Fig. shows the characteristics of the
The time characteristic of the relay is automatically
determined by the setting of the ratio of the voltage
to close the right contacts to the voltage to close
the left contacts.
The time-voltage curves are plotted in per cent
thus making them applicable for all tap settings.
Inspection
At
the time of installation, the relay should be
inspected for tarnished contacts, loose screws, or
other imperfections. If any trouble is found, it
should be corrected in the manner described under
maintenance.
GEH-12668
View
View
IA V54A IA VSSA
and the
IA V53A.
9