Instruction manual

KRB-5377
72
5-4. OCR Function Check
CAUTION
z OCR function check and setting changes must be performed by competent persons.
z After completion of OCR tests, be sure to return the settings to the original values. Failure to do so may cause a fire or
burnout.
Use the following procedure to perform OCR function check.
1) Open the ACB and draw out the breaker body to the TEST position.
2) Change settings according to the test as shown in Table 36.
Table 36 OCR setting changes
Test *1 Output signal value Setting to be changed
L characteristic: [IR] × 6
Non
R characteristic: [IR] × 3
NonLong time delay trip
S characteristic: [IR] × 1.2
Non
Short time delay trip
[Isd] × 1.2 [Ii] >[Isd] × 1.5, Short time delay trip I
2
t protection: OFF
Instantaneous trip Mode: INST
MCR
[Ii] × 1.2
Mode: MCR
Ground fault trip
[I
g] × 1.5
Ground fault trip I
2
t protection: OFF
*1 Setting an item to NON and OFF disables the test for the item.
3) To check the ACB along with the OCR, close the ACB before applying a test signal. When checking the MCR function, close
the ACB within 0.3 sec. after applying a test signal.
4) Follow the procedure described in Fig. 67 and Table 37 to check the OCR for normal operation. (In NTR mode, the ACB does
not operate, a trip/alarm event is not saved in the log and operation indication contact output is not provided).