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IB 7.2
.
1.7
-
1
A
Addendum A
Page 2
Type 51 Time
-
Overcurrent Relays
TESTING
Test connections are readily made
to the drawout relay unit by
means
of standard banana plugs
.
Current connections are made to the vertical posts at the blade assemblies
.
Control power and
output
connections are made at the rear vertical printed circuit board
.
This rear board is marked for easier
identification of the connection points
.
A typical calibration test circuit is shown in Fig
.
4
,
pg
.
19
of IB
7.2
.
1.7
-
1
.
Note : when testing Series 423 relays
, jumpers must be installed between terminals 9
-
10
-
11
on the
rear circuit board to complete the torque control circuits for proper operation
.
The jumpers must be
removed before re
-
inserting the relay in its
case
.
TEST PLUG
A test plug assembly
,
catalog number 400 X 0001 is available for use with the 423 series units
.
This
device plugs into the relay case on the switchboard and allows access to all external circuits wired to
the case
.
See Instruction Book IB 7.7
.
1.7
-
8
for details on the use of this device
.
Note
: the X 51 C Overcurrent Relay Test Accessory is not compatible with 423 series units
.
MAINTENANCE
Should separation of the upper and lower circuit boards be necessary , remove ( 2 ) screws that attach
the left and right handle assemblies to the upper printed circuit board
.
The lower board may then be
withdrawn forward from the printed circuit connector
.
A ten point extender
board is available from the
factory if access to the lower circuit board
is required during testing or troubleshooting
.
These instructions do not purport
to
cover all details or variations in equipment nor to provide for
every possible contingency to be
met
in connection with installation
,
operation or maintenance
.
Should further information be desired or should particular problems arise which are not covered
sufficiently for the purchaser
'
s purposes , the
matter should be referred to
Asea Brown Boveri
.
ABB Power T
&
D Company
,
Inc
.
Protective Relay Division
Rev
.
2 ( 3
/
90 )
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