Technical Data
Effective: May 1998
Page
4
TD.44A.01.T.E
Cutler-Hammer
Magnum DS
Metal-Enclosed
Low-Voltage Switchgear
Ratings
The narrow-band characteristic curve
graphically illustrates the close coordi-
nation obtainable in breaker systems
with Digitrip RMS tripping devices.
Repeatability is within 2%.
The maximum breaker current rating
for any breaker frame size is deter-
mined by the rating of the sensor used.
The breaker current rating for any
frame size can be changed by simply
changing the sensors and associated
rating plug, which are easily removed
from the breaker draw-out element.
The wide range of long-delay pickup
makes one set of sensors more flexible
on a wider range of loads. The Digitrip
RMS itself need not be changed when
the associated sensors and rating
plugs are changed.
Digitrip RMS can be supplied in vari-
ous combinations of four indepen-
dent, continuously adjustable,
overcurrent protection functions:
■
Long delay (L)
■
Instantaneous (I)
■
Short delay (S)
■
Ground (G)
■
Ground Alarm only (GA)
Every Magnum DS trip unit comes
standard with LSI characteristics.
Optional ground (G) or ground alarm
(GA) may also be provided. These trip
units also provide the ability to defeat
instantaneous protection. In addition,
short delay protection may be set to
the maximum instantaneous level,
effectively disabling short delay pro-
tection if instantaneous protection is
turned off. Under no condition is it
possible to set the trip unit beyond the
capabilities of the circuit breaker.
Table R6 – Available Sensor Ratings
and Rating Plugs for Digitrip RMS
➀
Breaker
Frame
Available Ratings
800
200, 250, 300, 400, 600, 800
1600
200, 250, 300, 400, 600, 800,
1000, 1200, 1600
2000
200, 250, 300, 400, 600, 800,
1000, 1200, 1600, 2000
3200
2500, 3000, 3200
4000
3200, 4000
5000
3200, 4000, 5000
➀
The Rating Plug is for 50 and 60 Hertz appli-
cations. Rating Plugs are not interchangeable
with 60 Hertz or 50 Hertz only Rating Plugs.
Table R7 – Digitrip RMS Adjustable Trip Settings
Time/Current
Characteristics
Pickup Setting
Pickup Point
(see note)
Time Band, Seconds
Long Delay
0.4, 0.5, 0.6, 0.7, 0.8
0.9, 0.95, 1.0
I
n
Times
Long Delay Setting
2, 4, 7, 10, 12, 15, 20, 24
(at 6 times pickup value)
Instantaneous
Off, 2, 3, 4, 6, 10
M1
I
n
Times
Instantaneous Setting
Short Delay
2, 2.5, 3, 4, 6, 8, 10
M
1
I
r
Times
Short Delay Setting
0.1, 0.2, 0.3, 0.4, 0.5
(Flat Response)
0.1*, 0.3*, 0.5*
*(I
2
t Response)
Ground Fault
0.25, 0.3, 0.35, 0.4,
0.5, 0.6, 0.75, 1.00
(1200A Max.)
I
n
Times
Ground Fault Setting
0.1, 0.2, 0.3, 0.4, 0.5
(Flat Response)
0.1*, 0.3*, 0.5*
*(I
2
t Response)
Note:
I
n
= Rating Plug Valve
I
r
= Long Delay Pickup Setting Times I
n
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