![background image](http://html1.mh-extra.com/html/eaton/magnum-ds/magnum-ds_technical-data-manual_4073436038.webp)
Technical Data
Effective: May 1998
Page
38
TD.44A.01.T.E
Cutler-Hammer
Magnum DS
Metal-Enclosed
Low-Voltage Switchgear
Features – Breaker
Magnum DS Switchgear – Trip Units
Digitrip RMS Trip Unit — The Digitrip
RMS trip units feature a dependent
curve that is depicted in the nameplate
by a blue shaded area of the trip curve.
The dependent curve affords better
protection flexibility. Additionally, all
of the trip units have, as standard, ther-
mal memory, 50/60 Hz operation, and
thermal self-protection at 90
°
C.
Also, the 520M trip units have a large
display window and 2% metering
accuracy.
Digitrip RMS Integral Microprocessor-
Based Breaker Overcurrent Trip
Systems — Provides maximum reli-
ability with true RMS sensing as stan-
dard, gives excellent repeatability, and
requires minimum maintenance. No
external control source is required for
its protective functions.
Trip Functions — Magnum DS trip
units provide the maximum in flexibil-
ity and are available in the following
configurations: LSI, LSIG, LSIGA
(ground fault alarm only). In each case,
either the short delay or instantaneous
(not both) functions may be defeated.
This reduces the need for spare
breaker inventories and provides maxi-
mum utilization of interchangeable
breakers.
Change in Trip Rating — The overcur-
rent trip pickup range is established by
a combination of trip unit rating plugs
and matching current sensor ratings
on the breaker.
Optional Breaker Attachments and
Accessories
a. Shunt trip on manually operated
breakers, for any standard control
voltage.
b. Auxiliary contacts on manually or
electrically operated breakers.
Maximum of 6 normally open and
6 normally closed contacts (5 nor-
mally closed contacts on electrically
operated breakers) are available on
any breaker, manually or electrically
operated. The contact rating is 10
amperes.
c. Compartment position switch, 6 or
12 contact, actuated by movement
of drawout breaker from the con-
nected position. Most common uses
are for disconnecting remote control
circuits of electrically operated
breaker, and for bypassing “b”
interlocking auxiliary contacts when
breaker is withdrawn from the con-
nected position.
d. Undervoltage trip (ac and dc avail-
able). Acts to trip the breaker when
the coil voltage is insufficient to
restrain a spring-loaded core. The
dropout point is within 30 to 60 per-
cent of the nominal coil voltage and
is not adjustable.
e. Overcurrent trip switch (OTS). A
latching type switch with two inde-
pendent FORM C contacts. Operates
only when the trip unit trips the
breaker. It may be used for alarm
and/or interlocking circuits. Reset-
ting is done by a pushbutton on the
breaker faceplate.
f. Electric close on manually operated
breakers, for any standard control
voltage. Breaker can be closed by
remote control switch or pushbutton
after the closing spring is manually
charged.
g. Operation counter.
h. Breaker mounted key interlock.
i. Second shunt trip coil in place of
UVR coil.
www
. ElectricalPartManuals
. com