Advertisement
I.L. 41-201S
Where the resistor is used, the pickup setting
can be adjusted from approximately 8% to 30%
of the continuous voltage rating. This setting is
made by adjusting the resistor. Note, however,
that the CV-8 time curves shown in Figure 10a
apply when the resistor is shorted out. Figure
10b applies when the resistor is set for 30% of
continuous voltage rating. Timing tests should be
conducted after the resistor is used to change
the pickup. This will verify proper coordination
time for the desired pickup setting.
7.1.4.3
Time Curve
Table 1 shows the time curve calibration points for
the various types of relays. With the time dial set to
the indicated position, apply the voltages specified in
Table 1 (e.g. for the CV-4, 140 percent of tap value
voltage) and measure the operating time of the relay.
The operating time should equal those of Table 1
plus or minus 5%. Note that the resistor, when used
in the CV-8, should be shorted when making this
measurement.
7.1.5.4
Indicating Contactor Switch (ICS)
Close the main relay contacts and pass sufficient dc
current through the trip circuit to close the contacts of
the ICS. This value of current should not be greater
than the particular ICS setting being used. The indi-
cator target should drop freely.
7.2.
Routine Maintenance
All relays should be inspected periodically and the
time of operation should be checked at least once
every year or at such other time intervals as may be
indicated by experience to be suitable to the particu-
lar application. Phantom loads should not be used in
testing induction-type relays because of the resulting
distorted current wave form which produces an error
in timing.
All contacts should be periodically cleaned. A contact
burnisher style number 182A836H01 is recom-
mended for this purpose. The use of abrasive mate-
rial for cleaning contacts is not recommended,
because of the danger of embedding small particles
in the face of the soft silver contact and thus impair-
ing the contact.
8.
CALIBRATION
Use the following procedure for calibrating the relay if
8
the relay has been taken apart for repairs, or the
adjustments have been disturbed. This procedure
should not be used until it is apparent that the relay is
not in proper working order (See "Performance
Check").
8.1. CV Unit
8.1.1. Contacts
a) By turning the time dial, move the moving con-
tacts until they deflect the stationary contact to a
position where the stationary contact is resting
against its backstop. The index mark located on
the movement frame should coincide with the "O"
mark on the time dial. For double trip relay, the
follow on the stationary contacts should be
approximately 1/64".
b) For relays identified with a "T" located at lower
left of stationary contact block, the index mark on
the movement frame will coincide with the "0"
mark on the time dial when the stationary contact
has moved through approximately one-half of its
normal deflection. Therefore, with the stationary
contact resting against the backstop, the index
mark is offset to the right of the "0" mark by
approximately .020". The placement of the vari-
ous time dial positions in line with the index mark
will give operating times as shown on the respec-
tive time-voltage curves. For double trip relays,
the follow on the stationary contacts should
be approximately 1/32".
8.1.2. Minimum Trip Voltage
The adjustment of the spring tension in setting the
minimum trip voltage value of the relay is most con-
veniently made with the damping magnet removed.
With the time dial set on "0", wind up the spiral spring
by means of the spring adjuster until approximately
6-3/4 convolutions show.
Set the relay on the minimum tap setting and the time
dial to position 6.
a) CV-4 and CV-5 overvoltage, CV-6 and CV-7
over or undervoltage
Adjust the control spring tension so that the mov-
ing contact will leave the backstop of the time
dial at tap value voltage +1.0% and will return to
the backstop at tap value voltage -1.0%.
Advertisement
