Cutler-Hammer Digitrip RMS 510, Инструкция по эксплуатации

Страница: 88 / 180

Page S
LOT will reset itself. You can of course, manually
clear the LOT (or any other trip indication) at any
time, by pushing the "PUSH to RESET" button.
(See Figure 1 .)
4.4 Short Delay Current Setting
There are eight (8) available Short Delay Current Set­
tings, as illustrated in Fig. 4.3. Six settings are in the
range from 2 to 6 times 1, and the other two settings are
"S1 " or "S2" times 1,. (REMEMBER:
l,
is the Long Delay
Current Setting). The values that "S1" and "S2" have
depend upon the type of circuit breaker, and are specified
both on the rating plug label {see Fig. 6), and on the
applicable Time-Current Curves referenced in
Section 9.0.
4.5 Short Delay Time Setting
As illustrated in Fig. 4.4, there are two different Short
Delay curve shapes, i .e., fixed time (flat) or 12t response.
The shape selected depends on the type of selective
coordination chosen. The 12t response will provide a
longer time delay in the low-end of the short delay current
range than will the flat response.
Available Settings
�
Short Delay
2, 2.5,
3,
4.
Setting
' ... �"":_.,.
5,
6, S,, S,
@) , I, to
M"l<lpiM ol
51
and
52
Values are Specified on Rating Plug
Fig. 4.3 Short Delay Current Settings
Five flat (. 1 , .2, .3, .4, .5 sec.) and three 12t (.1 *, .3*, .5*
sec.) response time delay settings are available. The 12t
response settings are identified by the suffix asterisk (*)
that appears in the viewing window. The 12t response is
applicable to currents less than eight (8) times 1,, the
Long Delay Setting. For currents greater than 8 times 1,,
the 12t response reverts to the flat response.
Note: See also Section 3.6, Zone Interlocking, above.
4.6 Instantaneous Current Setting
There are eight (8) available Instantaneous Current Set­
tings, as illustrated in Fig. 4.5. Six settings are in the
range from 2 to 6 times (In) the rating plug value, and the
I.L. 29-8858
other two settings are "M 1 " or "M2" times {In). The values
that "M1 " and "M2" have depend upon the type of circuit
breaker, and are specified both on the rating plug label
(see Fig. 6), and on the applicable Time-Current Curves
referenced in Section 9.0.
4.7 NO Instantaneous Current Setting
For types
LS
and
LSG
trip units, please see Sections 3.4
DIScriminator (Making Current Release) and 3.5 OVER­
RIDE (Fixed Instantaneous), for available fast-acting high
short-circuit protection.
4.8 Ground Fault Current Setting
The eight (8) G round Fault Current Settings are labeled
with the code letters "A" through "K" (except there are no
"G" or "I" settings), as illustrated in Fig. 4.6. In general,
the specific current settings range from 0.25 to 1 .0 times
(In), the rating plug value, but cannot exceed 1 200 A. The
specific Ground Current Settings for each letter are listed
in Table 1 and on the applicable Time-Current curve for
the breaker.
Sho.
•
Delay
Time
8]
Sec.
0
I ·' "-J
I
'-
,
' ,
"*"In Viewing Window
r")
Indicates
1 1
Ft Shape
w
8 X lr
Fig. 4.4 Short Delay Time Settings
.1, .2,
.
3
, .•
.5
Seconds w1 h
Flat Respon'
e
l't Shape
Returns to Flat
Response at
CurrE
1ts
Higher than
8
x
1,
.1*, .3*, .5*
Seconds with
Ft Shape
Effective May 1 997
www
. ElectricalPartManuals
. com