Effective 2/2/2001
Page 27
I.L. 70C1037H03
the Battery Check LED does not light green, replace the
battery. The condition of the battery has no effect on the
protection function of the trip unit. Even with the battery
removed, the unit will still trip the breaker in accordance
with its settings. However, without the battery, the Cause
of Trip LED will not flash red. If the battery is replaced, one
or more of the Cause of Trip LEDs may be illuminated.
Push the red Reset/Battery Test button to turn off the
indicators; the trip unit will be ready to indicate the next
cause of trip.
6.3 Battery Installation and Removal
The 3-volt lithium cell battery
(See Figure 6.1)
is easily
removed and replaced. The battery is located in the cavity
adjacent to the rating plug mounting screw, but is not part
of the rating plug. Insert a small screwdriver at the left side
of the rating plug, and to the left of the word OPEN, to
open the rating plug door. Remove the old battery by
pulling up on the removal tab that wraps under the battery
cell. When inserting the new cell, pay special attention to
ensure that the proper polarity is observed. The main body
of the battery is the positive (+) side.
Figure 6.1 Digitrip Battery
NOTE:
The battery can be replaced at any time, even
while the circuit breaker is in-service, without affecting the
operation of the circuit breaker or its protection functions.
CAUTION
EXERCISE CARE WHEN REPLACING THE BATTERY TO
ENSURE THAT THE CORRECT POLARITIES ARE
OBSERVED. POLARITY MARKINGS ARE SHOWN ON
THE RATING PLUG WHEN THE HINGED COVER IS
OPEN. ACCIDENTALLY INSTALLING THE BATTERY IN
THE REVERSE DIRECTION WILL NOT HARM EITHER
THE TRIP UNIT OR THE BATTERY, BUT WILL DEFEAT
THE FUNCTION OF THE BATTERY.
The replacement battery should be the same type as that
already in the trip unit or an equivalent. Acceptable 3.0 volt
lithium batteries may be obtained from the following
companies:
Company
Model
VARTA Batteries, Inc.
CR 1/3N
300 Elmsford Boulevard
Elmsford, N.Y. 10523
914-592-2500
(www.varta.com)
Duracell, Inc.
DL 1/3N
Berkshire Corporate Park
Bethel, CT 06801
1-800-551-2355
(www.duracell.com)
Sanyo Energy Corporation
CR 1/3N
2055 Sanyo Avenue
San Ysidro, CA 92173
619-661-6620
(www.sanyo.co.jp)
7.0 FRAME RATINGS (SENSOR RATINGS AND RATING PLUGS)
The frame rating
of a circuit breaker is the maximum RMS
current it can continuously carry. The maximum short-
circuit current rating of the circuit breaker is usually related
to the frame rating as well.
A current value, (
I
n), that is less than the full frame rating
may be chosen to be the basis for the coordination of the
protection function of the breaker without affecting its
short-circuit current capability. For the DT20 family of trip
units, this is implemented by changing the current sensors
and the corresponding
rating plug. These sensors and
rating plugs are available in kit form.
The current sensor rating is the maximum current the
circuit breaker can carry with the specified current sensors
installed. The sensor rating can be the same or less than
the frame rating, but not greater.
This value, (
I
n), is the basis for the trip unit current set-
tings:
1. The Instantaneous and Ground Current Settings (if
provided) are multiples of (
I
n) (see Sections 4.6
and 4.7).
2. The Long Delay Current Setting, (
I
r), is a fractional
multiple of (
I
n): Long Delay Current Setting = (
I
r) = LD
x (
I
n) (see Section 4.2).
