ABB COV-6 Памятка по эксплуатации - Страница 4
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41-116.1C
for steel panel mounting.
For detail information on the FT case refer to IL
41-076 for semi-flush mounting.
Ref. Dwgs: External Schematic (Figure 10, page 19)
Outline and Drilling Plan (Figure 11,
page 20)
6.0 ACCEPTANCE TEST
!
High currents left on for excessive time periods
can result in the softening and possible melting
of the insulation of the interconnecting wires.
The proper adjustments to insure correct operation of
this relay have been made at the factory. Upon
receipt of the relay, no customer adjustments, other
than those covered under "RELAY SETTINGS",
should be required.
The following check is recommended to insure that
the relay is in proper working order. (See Figure 9,
page 18.)
6.1
OVERCURRENT UNIT (CO)
The directional unit contacts must be in the closed
position and the "T" unit picked up when checking the
operation of the overcurrent unit.
A. Contact
1) By turning the time dial, move the moving
contacts until they deflect the stationary con-
tact to a position where the stationary contact
4
CAUTION
Magnet Adjustment
Time
Current
Relay
Dial
(Multiples of
Type
Position
Tap Value)
6
6
7
6
8
6
9
6
11
6
* For 50 hertz COV-11 relay, 20 times operating time limits are 0.24 + 20%, -5%
COV Voltage Controlled Overcurrent Relay
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 relays, the follow on the sta-
tionary contacts should be approximately
1/64".
2) For relays identified with a "T", located at
lower left of stationary contact block, the
index mark on the movement frame will coin-
cide with the "O" mark on the time dial when
the stationary contact has moved through
approximately one-half of its normal deflec-
tion. Therefore, with the stationary contact
resting against the backstop, the index mark
is offset to the right of the "O" mark by
approximately .020". The placement of the
various time dial positions in line with the
index mark will give operating times as shown
on the respective time-current curves. For
double trip relays, the follow on the stationary
contacts should be approximately 1/32".
B. Minimum Trip Current – Set the time dial to
position 6. Alternately apply tap value current
plus 3% and tap value current minus 3%. The
moving contact should leave the backstop at
tap value current plus 3% and should return to
the backstop at tap value current minus 3%.
C. Time Curve – Table 1 shows the time curves
calibration points for the various types of
relays. With the time dial set to the indicated
position, apply the currents specified by Table
1 (e.g., for the COV-8, 2 and 20 times tap value
Table 1:
Permanent
Operating
Current
Time
(Multiples of
(Seconds)
Tap Value)
2
2.46
2
4.27
2
13.35
2
8.87
2
11.27
Electromagnet
Plug Adjustment
Operating
Time
(Seconds)
20
1.19
20
1.11
20
1.11
20
0.65
20
0.24*