Eaton Digitrip 520 - Short delay time setting; Instantaneous current setting; Ground fault current setting

24
Instructional Leaflet IL70C1037H05
Effective October 2009
Digitrip models 520, 520i; and 520M, 520Mi,
520MC, 520MCi trip units for use only in
Magnum and Magnum DS circuit breakers
EATON CORPORATION www.eaton.com
Figure 34. Short Delay Time Settings
Five FLAT (0.1, 0.2, 0.3, 0.4, 0.5 seconds) and three I
2
t (0.1*, 0.3*,
0.5* seconds) response time delay settings are available. The I
2
t
response settings are identified by an asterisk (*). The I
2
t response
is applicable to currents less than eight times the ampere rating of
the installed rating plug (I
r
). For currents greater than 8 x (I
r
), the I
2
t
response reverts to the FLAT response.
otes:N Also see Section 3, zone interlocking.
Short Delay Time
0.4 Seconds
Available Settings
0.1, 0.2, 0.3,
0.4, 0.5
Seconds with
FLAT Response
l
2
t Shape
Returns to FLAT
Response at
Currents Higher
than 8 x l
r
*0.1, *0.3, *0.5
Seconds with
l
2
t Shape
8 x l
r
*Indicates l
2
t Shape
Instantaneous current setting
There are eight available instantaneous current settings, as
illustrated in Figure 35. Six settings are in the range from 2–10 x
(I
n
) the rating plug value, and the other two settings are M1 x (I
n
) or
OFF. The value that M1 has depends upon the sensor rating of the
circuit breaker and is specified both on the rating plug label and on
the applicable time-current curves referenced in Section 9.
Figure 35. Instantaneous Current Settings
Ground fault current setting
The eight ground fault current settings are labeled with values from
0.25 to 1.0 x (I
n
) (see Figure 36). The domestic (U.S.) models have
a maximum of 1200A, limited by the firmware of the unit, as shown
in Table 1 and Table 4. The specific ground current settings for each
model are listed in Table 4 and on the applicable time-current curve
for the breaker.
Figure 36. Ground Fault Current Settings
Ground fault time delay setting
As illustrated in Figure 37, there are two different ground fault
curve shapes: fixed time (FLAT) or I
2
t response. The shape selected
depends on the type of selective coordination chosen. The I
2
t
response will provide a longer time delay for current below
0.625 x I
n
than will the FLAT response.
Five FLAT (0.1, 0.2, 0.3, 0.4, 0.5 seconds) and three I
2
t (0.1*, 0.3*,
0.5* seconds) response time delay settings are available. The I
2
t
response settings are identified by an asterisk (*). The I
2
t response
is applicable to currents less than 0.625 times the ampere rating of
the installed rating plug (I
n
). For currents greater than 0.625 x (I
n
), the
I
2
t response reverts to the FLAT response.
ote:N Also see Section 3, zone interlocking.
Setting Inst.
6 x l
n
Available Settings
2, 3, 4, 5, 6, 8,
10, M1, OFF*
In Multiples of
Rating Plug
Amperes (l
n
)
M1 value is specified on rating plug.
*No OFF on Digitrip 520—5LI style
Ground Fault
Setting
0.4 x l
n
Available Settings
0.25, 0.3, 0.35,
0.4, 0.5, 0.6,
0.75, 1.0
Specific Values
Given on Circuit
Breaker Time-
Current Curve
and in Table 4