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VISUAL INSPECTION
Check the nameplate stamping to insure
that the model number, rating and calibra-
. tion range of the relay received agree with
the requisition.
Remove the relay from its case and
check by visual inspection that there are no
broken or cracked molded parts or other
signs of' physical damage that may have
occurred in transit and that all screws are
tight.
MECHANICAL INSPECTION
The essentials of a mechanical inspec-
tion are to determine that all of the operating
elements are free from any tendency to
bind and are in correct adjustment as
specified below:
. L
The rotonoid -' The shaft end play in this
assembly is limited to insure proper clear-
ances between the armature and the spool
body.
The armature should rotate without
any tendency to bind.
2. The gear train - Check for end play in all
the shafts. Rotate the assembly by the roto-
noid and note that it moves with a steady
motion to the limit. of its travel. Permit
the assembly to reset reasonably fast to
check the action of the ratchet. See that the
pawl engages the gear teeth with positive
action.
Check all the set screws to see
that they are tight.
3. The time dial - Check the action of the
cams as they engage the timing contacts.
They should engage at the "V" section
on~y,
causing the contact to deflect and close WIth
about 1/64:" wipe.
The contact gap at the
TU-1 and TU-2 contact should be about
1/16".
"
.
4:. Telephone Type relays. - With
t~l.ephone
relays in the de-energIzed posibon all
circuit closing contacts should have a gap
of 0.015" and all circuit opening contacts
have a wipe of 0.005". Gap maybe checked
by inserting a feeler gage and wipe can be
checked by observing the amount of de-
flection on the stationary contact before
parting the contacts. The armature should
then be' operated by hand and the gap and
wipe again checked as described above.
5. Seal-In unit - The seal-in unit should be
checked as follows: The armature and seal-
in contacts should move freely when op-
erated by hand.
There should be a screw
in only one of the tap positions on the right
stationary contact strip. Operate the arma-
ture by hand and check that there is at
least 1/32" wipe on the seal-in contacts.
6. The targets - Operate the armature
and note that when the shield drops the
armature will continue to travel.
This
indicates. that the shield will have adequate
clearance when it falls.
ELECTRICAL TESTS
The following electrical tests are
recommended upon receipt of the relay.
1. Make time,tests.
2. Check minimum operating value of
telephone relay.
3. Check target and seal-in unit pickup .
values.
Check the time calibration using the
connections shown in Fig. 6.
Check the
operating time :;tt the
maximu~
time range
setting and agaro at some porot about 1/2
of the time range.
The relay timing ac-
curacy should be within the test limits
indicated in the section under CHARAC-
TERISTICS.
The test circuit is arranged
to include the seal-in unit time which was
not included in the factory time setting.
Howe:ver~
since this seal-in wiit time is
about 0.01 seconds, it will have little
effect on the final results.
Using connections shown in Fig. 7 the
telephone type relays should pick up at 80%
or less of rated voltage. When testing the
RPM15 relays the normally closed contacts
of the TY relay should blocked open and the
TU-2 (rear) contact should be closed manu-
ally.
This is to prevent the operation of
solenoid TU so that the regulation of the
test circuit will be adequate to permit
reliable test results.
Using connections shown in Fig. 7
check the targets and the seal-in unit
pickup. to confirm that they
:will
operate.
on rated current or less.
While making,
these .. test!:; the Qperating cams caIJ. be
manually held in the proper position to
keep the desired contact closed.
When
seal-in unit (SI) is picked up the opening of
switch "S" should not de-energize this
unit.
Connections can be made to the relay
studs but for panel-mounted relays a test
plug can be used to faCilitate the operation.
Since the rotonoid has only a one minute,
rating, the operator must be sure that this
solenoid is not damaged by overheating.
If
as a result of these tests any adjustments
are necessary, refer to the section on
SERVICING for information.
INSTALLATION PROCEDURE
If
after the ACCEPTANCE TESTS the
relay is held in storage before shipment to
the job site, it is recommended that the
visual and mechanical inspection described
under the section on ACCEPTANCE TESTS
be repeated before installation.
It
is also
advisable to check the specific time settings
that are to be used.
PERIODIC CHECKS AND
ROUTINE MAINTENANCE
In view of the vital roll of protective
relays in the operation of a power system
it is important that a periodic test program
be followed.
It
is recognized that the interval
between periodiC checks will vary depending
upon environment, type of relay and the
user's experience with periodic testing.
. Until the user has accumulated enough
experience to select the test interval best
suited to his individual requirements, it is
suggested that the following points be check-
ed at an interval of from one to two years.
ELECTRICAL TEST
Using connections shown in Fig. 6 check
the operating time of the TU-1 and TU-2
contaCts at rated voltage and present time
Timing Relays Type RPM
GEH-2031
setting to be sure they are within the limits
specified under ACCEPTANCE TEST and,
that the targets operate properly.
If
for any reason the operating times
are outside these limits, refer to the
SERVICING section.
SERVICING
CONTACT CLEANING
For cleaning fine silver contacts, a
. flexible burnishing tool should be used.
This consists of a flexible strip of metal
with an etched roughened'surface, resem-
bling in effect a superfine file. Thepolish-
ing action is so delicate that no scratches
are left, yet corroded material will be
removed rapidly and thoroughly.
The
flexibility of the tool insures the cleaning
• of the actual points of contact.
Fine silver contacts should not be
-cleaned with knives, files or abrasive paper
or cloth.
Knives or files may leave
. scratches which increase arcing and de-
terioration of the contacts. Abrasivepaper
or cloth may. leave minute particles of in-
sulating abrasive material in the coritacts,
thus prevent closing.
,
A burnishing tool as described above
can be obtained from the factory.
MECHANICAL ADJUSTMENTS
The specific adjustments and setting
on this relay should rarely require atten-
tion.
If
for one reason or another they
have been disturbed the following points
should be observed in restoring them:
1. The gap between the contact tips on
each set of the timing unit contacts should
be apprOximately 1/16 inch. Each contact
brush should bear against its respective
scraper brush.
.2. When rotated, the insulated cams should
touch the inner contact brush at the "V"
only, but high enough on the "V" to insure
1/64: inch wipe on the 'outer contact brush.
These cams should not extend beyond the
edge of their respective contact brush.
3. With the pointer 'of the rear insulated
cam set at the maximum time setting on
the scale, this cam should rotate, far
enough beyond the apex of the "V" in the
contact brush to allow the contacts to re-
, open when the timing unit is fuily operated.
4. There should be at least 1/32 inch
clearance between the time scale assembly
and the front mounting
plate~
5. There should be no binding between
the gear on the main shaft and the pinion
on the magnetic damping element shaft.
6. The pawl of the ratchet assembly on
the magnetic damping element shaft should
'remain engaged
to
the same tooth when
the time scale is rotated from zero to 'the
maximum time setting mark and should
allow the gear to slip when the scale is
released.
7. The flexible stop arm at the rear of
the main shaft should clear the supporting
bracket by at le::tst 1/32 inch.
.
7
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