UNITED STATES DEPARTMENT OF AGRICULTURE

Rural Electrification Administration

**BULLETIN 1751E-302**

**SUBJECT:** **[Power Requirements for Digital Central Office
Equipment]{.underline}**

**To:** All Telephone Borrowers

REA Telephone Staff

**EFFECTIVE DATE:** Date of Approval

**EXPIRATION DATE:** Three years from effective date

**OFFICE OF PRIMARY INTEREST:** Central Office Equipment Branch,

Telecommunications Standards Division

**PREVIOUS INSTRUCTIONS:** This bulletin replaces REA

Telecommunications Engineering & Construction Manual (TE&CM) Section
302, Power Requirements for Community Central Office Equipment, Issue
No. 6, dated April 1989.

**FILING INSTRUCTIONS:** Discard REA Telecommunications Engineering &
Constructions Manual (TE&CM) 302, Power Requirements for Digital Central
Office Equipment, Issue 6, dated April 1989, and replace it with this
bulletin. File with 7 CFR 1751 and on REANET.

**PURPOSE:** This bulletin provides REA borrowers, and other interested
parties with information concerning power requirements for digital
central office equipment.

James B. Huff Sr. 10/15/93

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Administrator Date

**TABLE OF CONTENTS**

1\.
GENERAL\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....4

2\. BASIS FOR
CALCULATIONS\...\...\...\...\...\...\...\...\...\...\...\.....4

3\.
CALCULATIONS\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...6

FIGURE 1 - NORTHERN TELECOM, DMS-100\...\...\...\...\...\...\....8

FIGURE 1.1 - NORTHERN TELECOM DMS-100 (EXAMPLE)\...\...\...\....9

FIGURE 1.2 - NORTHERN TELECOM DMS-100\...\...\...\...\...\...\....10

FIGURE 1.3 - NORTHERN TELECOM DMS-100 (EXAMPLE)\...\...\...\...11

FIGURE 1.4 - NORTHERN TELECOM DMS-10 400 SERIES\...\...\...\...12

FIGURE 1.5 - NORTHERN TELECOM DMS-10 400 SERIES (EXAMPLE)..13

FIGURE 1.6 - NORTHERN TELECOM DMS-10 400 SERIES\...\...\...\...14

FIGURE 2 - SIEMENS STROMBERG-CARLSON DCO DCO-E/DCO-SE\....16

FIGURE 2.1 - SIEMENS STROMBERG-CARLSON DCO DCO-E/DCO-SE\....19

FIGURE 3 - REDCOM MDX\...\...\...\...\...\...\...\...\...\...\...\...22

FIGURE 4 - AT&T 5ESS SWITCH\...\...\...\...\...\...\...\...\...\...23

FIGURE 4.1 - AT&T 5ESS SWITCH (EXAMPLE)\...\...\...\...\...\.....25

FIGURE 5 - MITEL GX5000\...\...\...\...\...\...\...\...\...\...\....27

FIGURE 5.1 - MITEL GX5000 (EXAMPLE)\...\...\...\...\...\...\...\...28

FIGURE 6 - TRANSMISSION ELECTRONICS CURRENT DRAIN\...\.....29

FIGURE 7 - ESTIMATING TELEPHONE BATTERY SIZES\...\...\...\...30

FIGURE 8 - CHARGER CAPACITY\...\...\...\...\...\...\...\...\...\...31

INDEX:

Power Requirements For Digital Central Office Equipment

**ABBREVIATIONS**

AC Alternating Current

AH Ampere Hour

AM Administrative Module

AMAF Automated Message Accounting Frame

BHA Busy Hour Attempts

BMC Billing Media Converter

BTU British Thermal Unit

CC Common Control

CCS Hundred Call Seconds

CM Communication Module

CMF Control and Maintenance Frame

COE Central Office Equipment

CPU Central Processing Unit

CUA Circuit Unit Assembly

DAT Digital Analog Trunk

DC Direct Current

dc-ac direct current - alternating current

dc-dc direct current - direct current

DCI Digital Carrier Interface

DCM Digital Carrier Module

DCO-E Digital Central Office Exchange

DCS-SE Digital Central Office Small Exchange

DCTU Digital Carrier Trunk Unit

DLTU Digital Line & Trunk Unit

DTC Digital Trunk Controller

DTMF Dual - Tone Mutlifunction

GDSU Global Digital Service Unit

GPIO General Purpose Input Output

LCE Line Concentrating Equipment

LCE Line Concentrator Equipment

LGC Line Group Controller

LLS Local Line Switch

LTF Line Trunk Frame

LU Line Unit

MDX Modular Digital Exchange

MMSU Modular Metallic Service Unit

MSU Modular Shelf Unit

MTM Maintenance Trunk Module

OPM Outside Plant Module

OPSM Outside Plant Subscriber Module

P.E. Peripheral Equipment

PCCM Power Cooling Control Module

PDC Power Distribution Center

PWBA Printed Wire Board Assembly

RLCM Remote Line Concentrator Module

RLG Remote Line Group

RSLE Remote Line Subscriber Equipment

RSLM Remote Subscriber Line Module

SCM Subscriber Carrier Module

SLC Subscriber Loop Carrier

T&M Trunk and Maintenance

TM Trunk Module

TMF Toll Multifunction

TU Trunk Unit

v volts

**1. GENERAL**

**1.1** This bulletin is intended to provide REA borrowers, consulting
engineers, contractors and other interested parties with technical
information for use in the design and construction of REA borrowers\'
telephone systems. It discusses, in particular, the methods used in
calculating the power requirements for central offices. It provides
means to calculate the required capacities of the storage batteries and
charging equipment for particular applications.

**1.2** This bulletin replaces REA TE&CM 302, Power Requirements for
Digital Central Office Equipment, Issue No. 6, dated April 1989. This
bulletin provides power calculation methods for various digital, stored
program controlled central office equipment.

**1.3** General specifications governing storage battery and charging
equipment for proposed Central Office Equipment (COE) are covered in
Items 12.1 and 12.2, Part III, of Bulletin 1753E-001 (Form 522), \"REA
General Specification for Digital, Stored Program Controlled Central
Office Equipment.\" Based on these general specifications, determination
of the required capacities of battery and charger is made by the
manufacturer.

**2. BASIS FOR CALCULATIONS**

**2.1** Charging equipment furnished with a central office should have
sufficient capacity to supply the dc power necessary for the
satisfactory operation of the office during the busy hour. This includes
the dc requirements for carrier, loop extenders, voice frequency
repeaters, and dc-dc converters or dc-ac inverters to operate
input/output devices.

**2.1.1** Determination of the requirements for emergency generating and
charging equipment is covered in Bulletin 1751E-320, \"Emergency
Generating and Charging Equipment.\" A suggested method of charger size
computation is provided in Figure 8.

**2.2** Charging equipment for digital central offices should be
provided on one of the following bases:

\(a\) Two chargers either of which is capable of carrying the

full office load; or

\(b\) Three chargers each of which is capable of carrying

half the office load.

Arrangement (a) may be used in any central office power system.
Arrangement (b) may offer potential cost savings when applied to power
requirements in relatively large digital, stored program controlled
offices.

**2.3 [Storage Battery]{.underline}**

**2.3.1** The storage battery furnished with a central office should
have sufficient capacity to supply the dc power necessary to sustain
satisfactory operation of the exchange for the period specified.

Specific REA minimum requirements are in 7 CFR 1755.522, which is also
contained in Part III of REA Bulletin 1753E-001 (Form 522). Appropriate
allowances should be included for any equipment which is normally ac
operated but arranged for dc operation in case of an ac failure. See
paragraph 1.3 of this bulletin for location of specific requirements in
central office equipment specifications.

**2.3.2** The minimum usable voltage to be delivered to the central
office equipment during battery discharge should be determined using COE
manufacturer\'s design criteria. When power flows from the battery
through the power board to the equipment, a voltage drop (IR loss) is
experienced as a result of the resistance of the current carrying
conductors. In many cases equipment design is based on 44 volts being
available at the power entry to the bay. Performance of the digital COE
at voltages less than 44 volts becomes unpredictable. For effective
design, voltage drop from the source to the equipment bay is considered
by allocation as follows:

Battery to Power Board 0.5

Power Board to Equipment Bay 0.5

Minimum Equipment Voltage [44.0]{.underline}

Total 45V dc - 45.0 Vdc

In the case of a 24-cell battery (45/24) = 1.88 volts per cell becomes
the minimum operating voltage.

**2.3.3** The computation of battery size to meet the site power
requirement is described in Figure 7 - Estimating Telephone Battery
Sizes. This method permits computation with differing numbers of hours
of reserve and numbers of cells in the battery string. The computation
is applicable to lead-acid batteries, lead antimony, or lead-calcium
batteries (see manufacturer\'s data for capacity, dimensions, etc.).

**2.3.4** REA recommends that the battery provided should have the
capacity to maintain the central office load for a period of 8 hours.
Systems that are equipped with emergency generators are allowed to
reduce the 8 hours to a 3-hour reserve time.

**2.3.5** Determination of battery capacity to be supplied should be
based on power outages experienced at the site and on the evaluation of
the future performance of the ac power system. Another consideration is
the size of the dc load to be supplied. Small electromechanical
switching systems have a limited amount of fixed power consuming
devices, while a large part of system devices only require power when in
use. As a result battery capacity determinations were made assuming busy
hour switching activity. The telecommunications industry considers 8
busy hour battery capacity appropriate for most small installations. The
expectation of 8 consecutive busy hours of usage following a power
interruption was negligible, resulting in battery power being usable for
longer than the 8-hour period. Power consumption in digital switching
equipment is almost constant, whether or not calls are being processed.
In addition, the total power consumed by digital switches is greater
than the electromechanical systems. The concept of \"busy hour drain\"
has lost its impact in digital offices where the operating drain
represents the constant load. The solution most often used is to provide
an emergency generator to supply power on a long-term basis and to
install a battery with 3 hours capacity.

**3. CALCULATIONS**

**3.1** The following sample calculations describe the suggested
procedure to determine the power requirements for digital, stored
program controlled central office equipment. Sample calculations are
included for the following switching equipment types:

System

[Manufacturer]{.underline} [Designation]{.underline}

Figure 1 - Northern Telecom DMS-100, DMS-10

Figure 2 - Siemens Stromberg-Carlson DCO

Figure 3 - Redcom MDX

Figure 4 - AT&T 5 ESS

Figure 5 - Mitel GX5000

**3.2** Figure 6 lists various power requirements for loop extenders,
voice frequency repeaters, carrier equipment and other equipment.

**3.3** Figure 7 illustrates the method used in determining the capacity
of a storage battery required for a particular application. This figure
also illustrates, in Example 2, a method for calculating the ampere-hour
reserve of existing batteries when the current requirement of the
central office equipment is changed as a result of equipment additions
or higher than anticipated calling rates, etc.

**3.4** Figure 8 illustrates the suggested method used in determining
charger capacity required for a particular application. If 110 percent
of the rated output of the charger is equal to or greater than the
calculated charger dc current requirement, the charger is considered as
satisfactorily meeting the specification requirements. Three suggested
solutions in terms of the number of chargers and their capacity are
included.

**3.5** In some cases specialized equipment requires power at a voltage
different from the -48V dc central office battery. Dc-dc converters can
be supplied at [+]{.underline}24V dc, [+]{.underline}48V dc,
[+]{.underline}130V dc and other values. These other voltages are used
to supply radio and carrier equipment operated at -24 volts, coin
collect circuits at [+]{.underline}130 volts and other equipment. The
power required by the dc-dc converters has to be included in the total
load to be carried by the central office dc power system.

**3.6** It should be kept in mind that the calculation methods shown in
this section are to provide estimates only. Engineering judgment has to
be used for each individual application. It is, therefore, recommended
that the manufacturer of the system be consulted for specific
applications.

Figure 1 NORTHERN TELECOM DMS-100

[DC DRAIN]{.underline}

1\. Basic (CPU) [78.5]{.underline}

CC Frame E/W 4 Memory Shelves

I/O Frame E/W 2 Disk + 1 Mag Tape

2\. PDC Bays x 6.5 Amps \_\_\_\_\_

3\. LAMA or CAMA (10 Amps) \_\_\_\_\_

4\. Combined Network Frame x 24 Amps \_\_\_\_\_

5\. Double Shelf Network x 14 Amps \_\_\_\_\_

6\. DTC x 8.5 Amps \_\_\_\_\_

7\. MTM x 3.3 Amps \_\_\_\_\_

8\. TM x 2.2 Amps \_\_\_\_\_

9\. LGC x 8.5 Amps \_\_\_\_\_

10\. Line Circuits LCE \_\_\_\_\_\_\_ x 8.2 + 4W (Note 1) \_\_\_\_\_

Subtotal \_\_\_\_\_

Customer Drain \_\_\_\_\_\_\_ \_\_\_\_\_

**DMS Current Total \_\_\_\_\_\_\_** \_\_\_\_\_

Note 1: W = 2 way CCS per line in unit drain formula

Figure 1.1 NORTHERN TELECOM DMS-100

[E X A M P L E]{.underline}

1000 Lines, 50 Digital Trunks, 50 Analog Trunks, 3.2 CCS/Line

[DC DRAIN]{.underline}

1\. Basic (CPU) [78.5]{.underline}

CC Frame E/W 4 Memory Shelves

I/O Frame E/W 2 disk + 1 Mag Tape Drive

2\. PDC Bays [1]{.underline} x 6.5 Amps [6.5]{.underline}

3\. LAMA or CAMA, 10 Amps \_\_\_\_\_

4\. Combined Network Frame [1]{.underline} x 24 Amps [24.0]{.underline}

5\. Double Shelf Network x 14 Amps \_\_\_\_\_

6\. DTC [1]{.underline} x 8.5 Amps [8.5]{.underline}

7\. MTM [4]{.underline} x 3.3 Amps [13.2]{.underline}

8\. TM [1]{.underline} x 2.2 Amps [2.2]{.underline}

9\. LGC [1]{.underline} x 8.5 Amps [8.5]{.underline}

10\. Line Circuits LCE [1]{.underline} x 8.2 + 4W (Note 1)
[21.0]{.underline}

(Sample = 1 x 8.2 + 4 x 3.2 = 21)

Subtotal [162.4]{.underline}

Customer Drain [20]{.underline} [20.0]{.underline}

**DMS Current Total** [182.4]{.underline}

NOTE 1: W = 2 way CCS per line in unit drain formula

Figure 1.2 NORTHERN TELECOM DMS-100

[HEAT DISSIPATION]{.underline}

Heat

Dissipation

Per Frame Total Heat

[Type of Frame]{.underline} [Quantity]{.underline}
[(Watts/Hr)]{.underline} [Dissipation]{.underline}

Central Control Complex 1720 \_\_\_\_\_\_\_\_\_\_\_

Input/Output Frame 850 \_\_\_\_\_\_\_\_\_\_\_

Miscellaneous Equipment 220 \_\_\_\_\_\_\_\_\_\_\_

Network Combined 1000 \_\_\_\_\_\_\_\_\_\_\_

Digital Trunk Equipment 1120 \_\_\_\_\_\_\_\_\_\_\_

Trunk Module Equipment

Frame 480 \_\_\_\_\_\_\_\_\_\_\_

Line Concentrating

Equipment 1050 \_\_\_\_\_\_\_\_\_\_\_

Line Group Equipment 980 \_\_\_\_\_\_\_\_\_\_\_

Power Distribution Center 200 \_\_\_\_\_\_\_\_\_\_\_

**TOTAL WATTS/HOUR** \_\_\_\_\_\_\_\_\_\_\_

Figure 1.3 NORTHERN TELECOM DMS-100

[E X A M P L E]{.underline}

1400 Lines, 50 Digital Trunks, 50 Analog Trunks, 3.2 CCS/L

[HEAT DISSIPATION]{.underline}

Heat

Dissipation

Per Frame Total Heat

[Type of Frame]{.underline} [Quantity]{.underline}
[(Watts/Hr)]{.underline} [Dissipation]{.underline}

Central Control Complex [1]{.underline} 1720 [1720]{.underline}

Input/Output Frame [1]{.underline} 850 [850]{.underline}

Miscellaneous Equipment [1]{.underline} 220 [220]{.underline}

Network Combined [1]{.underline} 1000 [1000]{.underline}

Digital Trunk Equipment [1]{.underline} 1120 [1120]{.underline}

Trunk Module Equipment

Frame [2]{.underline} 480 [960]{.underline}

Line Concentrating

Equipment [1]{.underline} 1050 [1050]{.underline}

Line Group Equipment [1]{.underline} 980 [980]{.underline}

Power Distribution Center [1]{.underline} 200 [200]{.underline}

**TOTAL WATTS/HOUR** 8100

Figure 1.4 NORTHERN TELECOM STANDARD DMS-10 400 SERIES

[DC DRAIN]{.underline}

Basic System [25.0]{.underline} Amps

DCM Shelves x [4.0]{.underline} = Amps

DCI Shelf x [3.0]{.underline} = Amps

SCM-10S x [10.0]{.underline} = Amps

P.E. Shelf x [0.75]{.underline} = Amps

LCE Lines x [0.015]{.underline} = Amps

BMC x [5.0]{.underline} = Amps

D.C./A.C. Inverter (0.5 KW)\_\_\_\_\_\_\_\_ x 15 = Amps

**Total =** Amps

[Heat Dissipation]{.underline}

D.C. Drain

Northern Telecom DMS-10 400 Generic (3 Bay)

Basic System [30.0]{.underline} Amps

P.E. Shelf x [0.75]{.underline} = Amps

DCM Shelf x [4.0]{.underline} = Amps

LCE Lines x [0.015]{.underline} = Amps

**Total =** Amps

[Heat Dissipation]{.underline}

D.C. Drain x [52]{.underline} Watts

Figure 1.5 NORTHERN TELECOM STANDARD DMS-10 400 SERIES

[Example]{.underline} #1

5000 Lines, 576 Trunks, 1 RLCM, 1 SLC-96, 1 RSLE, 1 RSLM

@ 3.2 CCS/line

[DC Drain]{.underline}

Basic System [25.0]{.underline} Amps

DCM Shelves [4]{.underline} x [4.0]{.underline} = [16.0]{.underline}
Amps

DCI Shelf [1]{.underline} x [3.0]{.underline} = [3.0]{.underline} Amps

SCM-10S [1]{.underline} x [10.0]{.underline} = [10.0]{.underline} Amps

P.E. Shelf [2]{.underline} x [0.75]{.underline} = [1.5]{.underline} Amps

LCE Lines [5000]{.underline} x [0.015]{.underline} = [75.0]{.underline}
Amps

BMC [2]{.underline} x [5.0]{.underline} = [10.0]{.underline} Amps

D.C./A.C. Inverter (0.5 KW) [1]{.underline} x 15.0 = [15.0]{.underline}
Amps

**Total =** [155.5]{.underline} Amps

[Heat Dissipation]{.underline}

DC Drain [155.5]{.underline} x [52]{.underline} = [8086]{.underline}
Watts

[Example #2]{.underline}

Northern Telecom DMS-10 400 Generic (3 Bay)

1280 Lines, 144 Trunks, @ 3.2 CCS

Basic System [30.0]{.underline} Amps

P.E. Shelf [2]{.underline} x [0.75]{.underline} = [1.5]{.underline} Amps

DCM Shelf [1]{.underline} x [4.0]{.underline} = [4.0]{.underline} Amps

LCE Lines [1280]{.underline} x [0.015]{.underline} = [19.2]{.underline}
Amps

**Total =** [54.7]{.underline} Amps

[Heat Dissipation]{.underline}

D.C. Drain [54.7]{.underline} x [52]{.underline} = [2844]{.underline}
Watts

Figure 1.6 NORTHERN TELECOM STANDARD DMS-10 400 SERIES

(Page 1 of 2)

[1 - Standard 400 Series]{.underline} [AMPS]{.underline}

Basic System Current Drain 25.0

Network Module (Max. = 2 Modules) 12.0

DCM Shelf 4.0

DCI Shelf 3.0

SCM-10 (DMS-1) Shelf 4.0

SCM-10S (SLC-96) Module 10.0

Mag Tape Bay 7.8

BMC (each) 5.0

DC/AC Inverter 0.5 KW 15.0

DC/AC Inverter 1.0 KW 26.0

P.E. Lines 0.020

P.E. Shelf (with service circuits) 0.75

LCM Lines (per line) 0.015

[2 - DMS-10 400 Series (3 bay)]{.underline} [AMPS]{.underline}

Basic System Current Drain 30.0

(includes combination CPU/Network

shelf and GPIO shelf)

[3 - DMS-10 400 series (2 bay)]{.underline} [AMPS]{.underline}

CONTROL AND TRUNK BAY

CPU/Network Shelf (5.8 amps ea. [two required)]{.underline} 11.6

GPIO Shelf 4.8

T & M Shelf 2.9

PCCM Shelf 1.5

DAT Shelf 2.9

LINE AND TRUNK BAY

Two Shelf LCM (E/W 640 Lines) 9.6

Bay Supervisory Panel 0.2

DAT Shelf each (max. = 2 shelves) 2.9

[4 - DMS-10 400 Series (1 bay)]{.underline} [AMPS]{.underline}

CPU/Network Shelf (5.8 amps ea. [two required)]{.underline} 11.6

T & M Shelf 2.9

PCCM Shelf 1.5

DAT Shelf 2.9

FSP (Frame Supervisory Panel) and

LCM Shelf (E/W 256 lines) 4.8

Figure 1.6 NORTHERN TELECOM STANDARD DMS-10 400 SERIES

(Page 2 of 2)

[5 - OPM]{.underline} [AMPS]{.underline}

One Cabinet 15.0

Line Current 0.015/L

[6 - OPSM]{.underline} [AMPS]{.underline}

One Cabinet 9.0

Line Current 0.015/L

[7 - RSLM]{.underline} [AMPS]{.underline}

RSLM Bay 6.0

Line Current 0.015/L

[8 - RSLE]{.underline} [AMPS]{.underline}

RSLE Bay (up to 512 lines) 10.5

RSLE Bay (from 512 to 1024 lines) 21.0

Line Current 0.015/L

[9 - RLCM]{.underline} [AMPS]{.underline}

RLCM Bay 10.0

LCE Bay 0.015/L

Figure 2 SIEMENS STROMBERG - CARLSON DCO-E/DCO-SE

(Page 1 of 3)

[DC DRAIN]{.underline}

1\. [CONTROL & MAINTENACE FRAME (CMF)]{.underline} **WATTS**

DCO-E CMF (ONE PER DCO-E) [1]{.underline} X 2400 =\_\_\_\_\_

DCO-SE CMF (ONE PER DCO-SE) [1]{.underline} X 2000 =\_\_\_\_\_

2\. [LOCAL LINE SWITCH FRAME (LLS) (DCO-E & DCO-SE)]{.underline}

Quantity of Lines \_\_\_\_\_\_\_\_ x \_\_\_\_CCS/L X 0.069 (LOAD)
=\_\_\_\_\_

Quantity of Lines \_\_\_\_\_ X 0.158 (IDLE) =\_\_\_\_\_

Quantity Of Line CUAs \_\_\_\_\_ X 30.0 =\_\_\_\_\_

Quantity of RLG Host CUAs \_\_\_\_\_ X 31.0 =\_\_\_\_\_

Quantity of SLC Host CUAs \_\_\_\_\_ X 158.0 =\_\_\_\_\_

Quantity of LLS Frames \_\_\_\_\_ X 306.0 =\_\_\_\_\_

**TOTAL LLS FRAME POWER REQUIREMENTS** =\_\_\_\_\_

3\. [LINE/TRUNK FRAME POWER (LTF) (DCO-E ONLY)]{.underline} **WATTS**

Quantity of DTMF Receiver PWBAs \_\_\_\_\_ X 19.3 =\_\_\_\_\_

Quantity of DTMF Sender PWBAs \_\_\_\_\_ X 5.0 =\_\_\_\_\_

Quantity of TMF Receiver PWBAs \_\_\_\_\_ X 8.5 =\_\_\_\_\_

Quantity of TMF Sender PWBAs \_\_\_\_\_ X 3.9 =\_\_\_\_\_

Quantity of Busy Verification PWBAs \_\_\_\_\_ X 2.3 =\_\_\_\_\_

Quantity of Analog Trunk PWBAs \_\_\_\_\_ X 8.2 =\_\_\_\_\_

Quantity of LTF CUAs \_\_\_\_\_ X 19.3 =\_\_\_\_\_

**TOTAL LTF POWER REQUIREMENTS** =\_\_\_\_\_

4\. [DIGITAL TRUNK FRAME POWER (DTF) (DCO-E ONLY)]{.underline} **WATTS**

Quantity of T1 Interface PWBAs \_\_\_\_\_ X 11.2 =\_\_\_\_\_

Quantity of Message Assemblers \_\_\_\_\_ X 57.3 =\_\_\_\_\_

Quantity of DTF CUAs 67.4 =\_\_\_\_\_

**TOTAL DTF POWER (WATTS)** =\_\_\_\_\_

5\. [POWER RINGING & TEST FRAME POWER (PRTF) (DCO-E ONLY)]{.underline}
**WATTS**

Power Ringing & Test Frame [1]{.underline} X 92.0 = [92.0]{.underline}

**TOTAL PRTF POWER REQUIREMENTS** = [92.0]{.underline}

Figure 2 SIEMENS STROMBERG-CARLSON DCO-E/DCO-SE

(Page 2 of 3)

[DC DRAIN]{.underline}

6\. [DATA COLLECTION FRAME POWER (AMAF)/(DCF) (DCO-E &
DCO-SE)]{.underline} **WATTS**

AMA Frame (E/W Tape Drives) \_\_\_\_\_ x 495.0 =\_\_\_\_\_

CODC Data Collection Frame \_\_\_\_\_ X 523.0 =\_\_\_\_\_

**TOTAL AMAF/DCF POWER REQUIREMENTS** =\_\_\_\_\_

7\. [COMMON EQUIPMENT FRAME POWER (CEF) (DCO-E) & DCO-SE)]{.underline}
**WATTS**

Variable (Dependent on OEM Equipment Installed)

**TOTAL CEF POWER REQUIREMENTS** =\_\_\_\_\_

8\. [UNIVERSAL POWER FRAME (DCO-SE ONLY)]{.underline} **WATTS**

Universal Power Frame (UPF) [1]{.underline} X 92.0 = [92.0]{.underline}

Expanded Ringing CUA \_\_\_\_\_ X 70.0 =\_\_\_\_\_

\*Universal Service CUA \_\_\_\_\_ X 155.0 =\_\_\_\_\_

\*Universal Trunk/Service CUA \_\_\_\_\_ X 155.0 =\_\_\_\_\_

\*Universal Trunk CUA \_\_\_\_\_ X 132.0 =\_\_\_\_\_

\*Customber Trunk Group CUA \_\_\_\_\_ X 107.0 =\_\_\_\_\_

Quantity of DTMF Receiver PWBAs \_\_\_\_\_ X 19.3 =\_\_\_\_\_

Quantity of DTMF Sender PWBAs \_\_\_\_\_ X 5.0 =\_\_\_\_\_

Quantity of TMF Receiver PWBAs \_\_\_\_\_ X 8.5 =\_\_\_\_\_

Quantity of TMF Sender PWBAs \_\_\_\_\_ X 3.9 =\_\_\_\_\_

Quantity of Busy/Verification PWBAs \_\_\_\_\_ X 2.3 =\_\_\_\_\_

Quantity of Analog Trunk PWBAs \_\_\_\_\_ X 8.2 =\_\_\_\_\_

**TOTAL UPF POWER REQUIREMENTS** =\_\_\_\_\_

9\. [REMOTE LINE SWITCH POWER (RLS)]{.underline} **WATTS**

RLS Frame (1080 Lines Maximum) [1]{.underline} X 906.0
=[906.0]{.underline}

Quantity of Lines \_\_\_\_\_ X \_\_\_\_\_ CCS/L X 0.069 (LOAD)
=\_\_\_\_\_

Quantity of Lines \_\_\_\_\_ X 0.158 (IDLE) =\_\_\_\_\_

Quantity of Line CUAs \_\_\_\_\_ X 30.0 =\_\_\_\_\_

Quantity of RLG CUAs \_\_\_\_\_ X 31.0 =\_\_\_\_\_

Quantity of SLC CUAs \_\_\_\_\_ X 158.0 =\_\_\_\_\_

TOTAL RLS FRAME POWER REQUIREMENTS =\_\_\_\_\_

\*ONLY 3 CUAs TOTAL CAN BE EQUIPPED

Figure 2 STROMBERG-CARLSON DCO-E/DCO-SE

(Page 3 of 3)

[DC DRAIN]{.underline}

10\. [REMOTE LINE SWITCH - 450 POWER (DC)]{.underline} **WATTS**

Basic DC Power (Maximum) = [1200]{.underline}

Maximum Allowed Customer Power = [250]{.underline}

**RLS-450 DC POWER TOTAL WATTS (Maximum)** = [1450]{.underline}

RLS-450 RATED AC POWER INPUT (Typical) = [6000]{.underline}

(Based on cold weather heating plus maximum short term load.)

[SYSTEM DC POWER SUMMARY]{.underline}

11\. DCO-E SYSTEM POWER **WATTS**

Total Control & Maintenance Frame Power = [2400]{.underline}

Total Local Line Switch Power =\_\_\_\_\_

Total Line/Trunk Frame Power =\_\_\_\_\_

Total Digital Trunk Frame Power =\_\_\_\_\_

Total Power Ringing & Test Frame Power = [92.0]{.underline}

Total AMA/Data Collection Frame Power =\_\_\_\_\_

Total Common Equipment Frame Power =\_\_\_\_\_

**TOTAL DCO-E SYSTEM DC POWER REQUIREMENTS** =\_\_\_\_\_ AMPS

**TOTAL DCO-E DC BUSY HOUR LOAD (Total DC Power divided by**

**52.1 Volts)** =\_\_\_\_\_

12\. DCO-SE SYSTEM POWER **WATTS**

Total Control & Maintenance Frame Power = [2000]{.underline}

Total Local Line Switch Frame Power =\_\_\_\_\_

Total AMA/Data Collection Frame Power =\_\_\_\_\_

Total Universal Power Frame Power =\_\_\_\_\_

Total Common Equipment Frame Power =\_\_\_\_\_

TOTAL DCO-SE SYSTEM DC POWER REQUIREMENTS =\_\_\_\_\_

TOTAL DCO-SE DC BUSY HOUR LOAD =\_\_\_\_\_ AMPS

**(Total DC Power divided by 52.1 Volts)**

Figure 2.1 SIEMENS STROMBERG-CARLSON DCO-E/DCO-SE

(Page 1 of 3)

[Example]{.underline}

1000 LINES AT 3.2 CCS

1\. [CONTROL & MAINTENANCE FRAME POWER (CMF)]{.underline} **WATTS**

DCO-E [1]{.underline} X 2400 = [2400]{.underline}

DCO-SE [1]{.underline} X 2000 = [2000]{.underline}

2\. [LOCAL LINE SWITCH FRAME (LLS) (DCO-E & DCO-SE)]{.underline}
**WATTS**

Quantity of Lines [1000]{.underline} X [3.2]{.underline} CCS/L X 0.069
(LOAD) [220.8]{.underline}

Quantity of Lines [1000]{.underline} X 0.158 (IDLE) =
[158.0]{.underline}

Quantity of Line CUAs [12]{.underline} X 30.0 = [360.0]{.underline}

Quantity of RLG Host CUAs [0]{.underline} X 31.0 = [0]{.underline}

Quantity of SLC Host CUAs [0]{.underline} X 158.0 = [0]{.underline}

Quantity of LLS Host CUAs [1]{.underline} X 306.0 = [306.0]{.underline}

**TOTAL LLS FRAME(S) POWER (WATTS)** =[1044.8]{.underline}

3\. [LINE/TRUNK FRAME POWER (LTF) (DCO-E ONLY)]{.underline}

Quantity of DTMF Receiver PWBAs [2]{.underline} X 19.3 =
[38.6]{.underline}

Quantity of DTMF Sender PWBAs [2]{.underline} X 5.0 = [10.0]{.underline}

Quantity of TMF Receiver PWBAs [2]{.underline} X 8.5 =
[17.0]{.underline}

Quantity of TMF Sender PWBAs [2]{.underline} X 3.9 = [7.8]{.underline}

Quantity of Busy Verification PWBAs [2]{.underline} X 2.3 =
[4.6]{.underline}

Quantity of Analog Trunk PWBAs [0]{.underline} X 8.2 = [0]{.underline}

Quantity of LTF CUAs [2]{.underline} X 19.3 = [38.6]{.underline}

**TOTAL LTF POWER (WATTS)** = [116.6]{.underline}

4\. [DIGITAL TRUNK FRAME POWER (DTF) (DCO-E ONLY)]{.underline}

Quantity of T1 Interface PWBAs [5]{.underline} X 11.2 =
[56.0]{.underline}

Quantity of Message Assemblers [0]{.underline} X 57.3 = [0]{.underline}

Quantity of DTF CUAs [1]{.underline} X 67.4 = [67.4]{.underline}

**TOTAL DTF POWER (WATTS)** = [123.4]{.underline}

5\. [POWER RINGING & TEST FRAME POWER (PRTF) (DCO-E ONLY)]{.underline}

Power Ringing & Test Frame [1]{.underline} X 92.0 = [92.0]{.underline}

**TOTAL PRTF POWER (WATTS)** = [92.0]{.underline}

Figure 2.1 SIEMENS STROMBERG-CARLSON DCO-E/DCO-SE

(Page 2 of 3)

[Example]{.underline}

6\. [AMAF/DATA COLLECTION FRAME (AMAF/CODC) (DCO-E &
DCO-SE)]{.underline} **WATTS**

AMA Frame \_\_\_\_\_ X 495.0 =\_\_\_\_\_

CODC Data Collection Frame \_\_\_\_\_ X 523.0 =\_\_\_\_\_

**TOTAL AMAF/DCF POWER (WATTS)** = [0]{.underline}

7\. [COMMON EQUIPMENT FRAME POWER (CEF) (DCO-E) & DCO-SE)]{.underline}

Variable (Dependent on OEM Equipment Installed)

**TOTAL CEF POWER (WATTS)** = [0]{.underline}

8\. [UNIVERSAL POWER FRAME (DCO-SE ONLY)]{.underline} **WATTS**

Universal Power Frame (UPF) [1]{.underline} X 92.0 = [92.0]{.underline}

Expanded Ringing CUA X 70.0 =\_\_\_\_\_\_

\*Universal Service CUA X 155.0 =\_\_\_\_\_\_

\*Universal Trunk/Service CUA [1]{.underline} X 155.0 =
[155.0]{.underline}

\*Universal Trunk CUA [1]{.underline} X 132.0 = [132.0]{.underline}

\*Customber Trunk Group CUA [1]{.underline} X 107.0 =
[107.0]{.underline}

Quantity of DTMF Receiver PWBAs [2]{.underline} X 19.3 =
[38.6]{.underline}

Quantity of DTMF Sender PWBAs [2]{.underline} X 5.0 = [10.0]{.underline}

Quantity of TMF Receiver PWBAs [2]{.underline} X 8.5 =
[17.0]{.underline}

Quantity of TMF Sender PWBAs [2]{.underline} X 3.9 = [7.8]{.underline}

Quantity of Busy/Verification PWBAs [2]{.underline} X 2.3 =
[4.6]{.underline}

Quantity of Analog Trunk PWBAs [0]{.underline} X 8.2 = [0]{.underline}

**TOTAL UPF POWER (WATTS)** = [564.0]{.underline}

9\. [REMOTE LINE SWITCH POWER (RLS)]{.underline}

RLS Frame (1080 Lines Maximum) [1]{.underline} X 906.0 =
[906.0]{.underline}

Quantity of Lines [1000]{.underline} x [3.2]{.underline} CCS/L X 0.069 =
[220.8]{.underline}

Quantity of Lines [1000]{.underline} X 0.158 = [158.0]{.underline}

Quantity of Line CUAs [12]{.underline} X 30.0 = [360.0]{.underline}

Quantity of RLG CUAs \_\_\_\_\_ X 31.0 =\_\_\_\_\_\_

Quantity of SLC CUAs \_\_\_\_\_ X 158.0 =\_\_\_\_\_\_

**TOTAL RLS FRAME POWER (WATTS)** =[1644.8]{.underline}

\*ONLY 3 CUAs TOTAL CAN BE EQUIPPED

Figure 2.1 SIEMENS STROMBERG-CARLSON DCO-E/DCO-SE

(Page 3 of 3)

[Example]{.underline}

10\. [REMOTE LINE SWITCH - 450 POWER (DC)]{.underline} **WATTS**

TYPICAL Basic RLS-450 (Maximum) = [1200]{.underline}

CUSTUMBER POWER (250W Maximum) = [0]{.underline}

**TOTAL RLS-450 DC POWER TOTAL WATTS (Maximum)** = [1200]{.underline}

RLS-450 Rated Ac Power Input (Typical) = [6000]{.underline}

(Based on typical cold weather heating plus maximum short term system
load.)

11\. [SYSTEM DC POWER SUMMARY]{.underline}

1\. DCO-E SYSTEM POWER

Total Common Control Frame Power =[2400.0]{.underline}

Total Local Line Switch Power =[1044.8]{.underline}

Total Line/Trunk Frame Power = [116.6]{.underline}

Total Digital Trunk Frame Power = [123.4]{.underline}

Total Power Ringing & Test Frame Power = [92.0]{.underline}

Total AMA/Data Collection Frame Power = [0]{.underline}

Total Common Equipment Frame Power = [0]{.underline}

**TOTAL DCO-E SYSTEM DC POWER REQUIREMENTS** =[3776.8]{.underline}

**TOTAL DCO-E DC BUSY HOUR LOAD (TOTAL WATTS/52.1 VOLTS)** =
[72.5]{.underline} AMPS

12\. [DCO-SE SYSTEM POWER]{.underline}

Total Control & Maintenance Frame Power =[2000.0]{.underline}

Total Local Line Switch Frame Power =[1044.8]{.underline}

Total AMA/Data Collection Frame Power = [0]{.underline}

Total Universal Power Frame Power = [564.0]{.underline}

Total Common Equipment Frame Power = [0]{.underline}

**TOTAL DCO-SE SYSTEM DC POWER REQUIREMENTS** =[3608.8]{.underline}

TOTAL DCO-SE DC BUSY HOUR LOAD (TOTAL WATTS/52.1 Volts) =
[69.3]{.underline} AMPS

FIGURE 3 REDCOM MDX

[DC DRAIN]{.underline}

[Quantity]{.underline} [Multiply By]{.underline} [Amps]{.underline}

MSU Shelves (One per 40 Lines) \_\_\_\_\_\_\_\_\_\_ [3.5]{.underline}
\_\_\_\_\_\_\_

[HEAT DISSIPATION]{.underline}

Heat Dissipation (Watts) = 52.1 x DC Drain \_\_\_\_\_\_\_\_ =
\_\_\_\_\_\_\_ Watts

[E X A M P L E]{.underline}

150 Lines

[DC DRAIN]{.underline}

[Quantity]{.underline} [Multiply By]{.underline} [Amps]{.underline}

MSU Shelves (One per 40 Lines) [4]{.underline} [3.5]{.underline}
[14]{.underline}

[HEAT DISSIPATION]{.underline}

Heat Dissipation (Watts) = 52.1 x DC Drain [14]{.underline} =
[730]{.underline} Watts

FIGURE 4 AT&T 5ESS SWITCH

(Page 1 of 2)

[DC DRAIN]{.underline}

1\. Basic (AM and CM) [55.76]{.underline}

2\. No. of Disk Drive Units \_\_\_\_\_ x 1.30 Amps \_\_\_\_\_\_\_

3\. No. of Switching Modules w 32Mb Memory \_\_\_\_\_ x 9.94 Amps
\_\_\_\_\_\_\_

4\. No. of MMSUs \_\_\_\_\_ x 0.20 Amps \_\_\_\_\_\_\_

5\. No. of LUs \_\_\_\_\_ x 5.60 Amps \_\_\_\_\_\_\_

6\. No. of TUs \_\_\_\_\_ x 0.18 Amps \_\_\_\_\_\_\_

7\. No. of DCTUs \_\_\_\_\_ x 2.00 Amps \_\_\_\_\_\_\_

8\. No. of GDSUs \_\_\_\_\_ x 0.61 Amps \_\_\_\_\_\_\_

9\. No. of DLTUs \_\_\_\_\_ x 0.02 Amps \_\_\_\_\_\_\_

10\. No. of DLTU Packs \_\_\_\_\_ x 0.12 Amps \_\_\_\_\_\_\_

SUBTOTAL \_\_\_\_\_\_\_

Additional Drains \_\_\_\_\_\_\_

**TOTAL DC Drain** \_\_\_\_\_\_\_

FIGURE 4 AT&T 5ESS SWITCH

(Page 2 of 2)

[HEAT DISSIPATION]{.underline}

Heat

Dissipation

Per Frame Total Heat

[Type of Frame]{.underline} [Quantity]{.underline} [(BTUs)]{.underline}
[Dissipation]{.underline}

Basic (AM and CM) \_\_\_\_\_\_\_\_ 9931.42 \_\_\_\_\_\_

No. of Disk Drives \_\_\_\_\_\_\_\_ 231.54 \_\_\_\_\_\_

No. of Switching Modules \_\_\_\_\_\_\_\_ 1770.41 \_\_\_\_\_\_

No. of MMSUs \_\_\_\_\_\_\_\_ 36.27 \_\_\_\_\_\_

No. of LUs \_\_\_\_\_\_\_\_ 997.42 \_\_\_\_\_\_

No. of TUs \_\_\_\_\_\_\_\_ 32.95 \_\_\_\_\_\_

No. of DCTUs \_\_\_\_\_\_\_\_ 356.22 \_\_\_\_\_\_

No of GDSUs \_\_\_\_\_\_\_\_ 108.05 \_\_\_\_\_\_

No. of DLTUs \_\_\_\_\_\_\_\_ 174.55 \_\_\_\_\_\_

**TOTAL BTUs** \_\_\_\_\_\_

FIGURE 4.1 AT&T 5 ESS SWITCH

(Page 1 of 2)

[EXAMPLE]{.underline}

1 SM Office with 1000 Analog Lines,

12 Analog Trunks, and 192 Digital Trunk Circuits.

[DC DRAIN]{.underline}

1\. Basic (AM and CM) [55.76]{.underline}

2\. No. of Disk Drive Units [4]{.underline} x 1.30 Amps
[5.20]{.underline}

3\. No. of Switching Modules w 32Mb Memory [1]{.underline} x 9.94 Amps
[9.94]{.underline}

4\. No. of MMSUs [11]{.underline} x 0.20 Amps [2.20]{.underline}

5\. No. of LUs [3]{.underline} x 5.60 Amps [16.80]{.underline}

6\. No. of TUs [4]{.underline} x 0.18 Amps [0.72]{.underline}

7\. No. of DCTUs [1]{.underline} x 2.00 Amps [2.00]{.underline}

8\. No. of GDSUs [3]{.underline} x 0.61 Amps [1.83]{.underline}

9\. No. of DLTUs [1]{.underline} x 0.02 Amps [0.02]{.underline}

10\. No. of DLTU Packs [8]{.underline} x 0.12 Amps [0.96]{.underline}

SUBTOTAL [95.43]{.underline}

Additional Drains \_\_\_\_\_\_\_

**TOTAL DC Drain** [95.43]{.underline}

FIGURE 4.1 AT&T 5ESS SWITCH

(Page 2 of 2)

[EXAMPLE]{.underline}

1 SM Office with 1000 Analog Lines,

12 Analog Trunks, and 192 Digital Trunk Circuits

[HEAT DISSIPATION]{.underline}

Heat

Dissipation

Per Frame Total Heat

[Type of Frame]{.underline} [Quantity]{.underline} [(BTUs)]{.underline}
[Dissipation]{.underline}

Basic (AM and CM) [1]{.underline} 9931.42 [9931.42]{.underline}

No. of Disk Drives [4]{.underline} 231.54 [926.16]{.underline}

No. of Switching Modules [1]{.underline} 1770.41 [1770.41]{.underline}

No. of MMSUs [11]{.underline} 36.27 [398.97]{.underline}

No. of LUs [3]{.underline} 997.42 [2992.26]{.underline}

No. of TUs [4]{.underline} 32.95 [131.80]{.underline}

No. of DCTUs [1]{.underline} 356.22 [356.22]{.underline}

No of GDSUs [3]{.underline} 108.05 [324.15]{.underline}

No. of DLTUs [1]{.underline} 174.55 [174.55]{.underline}

**TOTAL BTUs** [17005.94]{.underline}

FIGURE 5 MITEL GX5000

D.C. DRAIN

EQUIPMENT QUANTITY MULTIPLY BY WATTS

First peripheral pair and Main

control (includes all features,

AMA, matrix and first cabinet) [1]{.underline} [460]{.underline}
[460]{.underline}

Additional peripheral pair [96]{.underline} \_\_\_

Additional cabinet [105]{.underline} \_\_\_

Single Party line card (16 ckts) [10]{.underline} \_\_\_

DS1 trunk card (2 spans) [29]{.underline} \_\_\_

Universal line card (6 ckts) [9]{.underline} \_\_\_

**Total D.C. Drain** Watts

Converted to AMPS (Watts/Battery Voltage) = Watts/52 = \_\_\_\_ Amps

Heat dissipation = \_\_\_\_\_ Watts or (3.41 X \_\_\_\_Watts) = \_\_\_\_
BTU

FIGURE 5.1 MITEL GX5000

[Example System]{.underline}: 1008 lines, 96 Digital Trunks

[D.C. DRAIN]{.underline}

EQUIPMENT QUANTITY MULTIPLY BY WATTS

First peripheral pair and Main

control (includes all features,

AMA, matrix and first cabinet) [1]{.underline} [460]{.underline}
[460]{.underline}

Additional peripheral pair [2]{.underline} [96]{.underline}
[192]{.underline}

Additional cabinet [1]{.underline} [105]{.underline} [105]{.underline}

Single Party line card (16 ckts) [63]{.underline} [10]{.underline}
[630]{.underline}

DSI trunk card (2 spans) [2]{.underline} [29]{.underline}
[58]{.underline}

Universal line card (6 ckts) [0]{.underline} [9]{.underline}
[0]{.underline}

**Total D.C. Drain** [1,445]{.underline} Watts

Converted to AMPS (Watts/Battery Voltage) = 1,445 Watts/52 = 27.7 Amps

Heat dissipation = 1,445 Watts or (3.41 X 1,445 Watts) = 4927 BTU

Figure 6 TRANSMISSION ELECTRONICS CURRENT DRAIN

48-Volt Battery Drain

[Amperes Per Unit]{.underline}

[Equipment]{.underline}

Loop Extenders 0.075

[VF Repeaters]{.underline}

1\. Negative Impedance 0.035

2\. Hybrid 0.035

3\. Automatic Gain Control 0.080

4\. Loop Extender/Repeater Combination 0.100

5\. Automatic Gain Control

Loop Extender/Repeater Combination 0.200

[Carrier Systems]{.underline}

1\. D1 or D2 3.0

2\. D3 (24 Channel) 0.7

3\. D4 (24 Channel) 0.35

4\. T1 Span Line 0.6

5\. Station Carrier (1 Channel) 0.04

6\. Station Carrier (Multi-Channel) Per Channel 0.1

7\. Pair Gain Devices (Switching)

(See Notes 1 & 2 for Office End)

[Echo Canceller]{.underline}

1\. VF (1 Channel) 0.075

2\. Digital (24 Channel) 1.7

[Remote Office Line Test]{.underline}

1\. Test Console (110V ac, 0.4A) 0.7

2\. Remote Terminal 0.7

120V, 60Hz Load

[Maintenance and Control Center]{.underline} [Amperes Per Unit (Note
3)]{.underline}

Co-located with COE:

Video Display (CRT) 0.5

Printer (1200 Baud) 0.5

Remotely Located:

Teletypwriter (e/w 300 Baud Modem) 0.35

NOTES:

1\. Refer to the manufacturer\'s data sheets for specific current drain

requirements.

2\. Line concentrators or other pair gain devices incorporating
switching

functions are generally locally powered at remote site.

3\. Voltage: 95 to 128V ac - Frequency: 48 to 65Hz

Figure 7 ESTIMATING TELEPHONE BATTERY SIZES

8-Hour Ampere Hour Capacity Required

[for Each Ampere of Load]{.underline}

Number of Hours Final Cell Voltages

[Reserve]{.underline} [1.75]{.underline} [1.80]{.underline}
[1.85]{.underline} [1.88]{.underline} [1.90]{.underline}
[1.95]{.underline}

1 2.2 2.5 2.8 3.2 3.5 5.0

2 3.2 3.4 3.7 4.3 4.7 6.2

3 4.0 4.3 4.7 5.2 5.6 7.5

4 4.9 5.1 5.6 6.1 6.5 8.6

5 5.7 6.0 6.5 7.0 7.4 9.6

6 6.5 6.8 7.3 7.8 8.2 10.6

7 7.2 7.6 8.1 8.7 9.1 11.6

8 8.0 8.3 8.9 9.6 10.0 12.6

9 8.8 9.1 9.6 10.4 10.9 13.7

10 9.5 9.9 10.4 11.4 12.0 15.0

Voltage (24 Cells) 42 43.2 44.4 45.1 45.6 46.8

[EXAMPLES]{.underline}:

1\. [Required]{.underline}: The capacity of a 24-cell battery to handle
a 3-hour load of 34.0 amperes to a limited voltage of 45 volts.

45/24 = 1.88

From the above chart, each ampere of load requires 5.2 ampere hours of
capacity.

Total capacity required = 5.2 x 34.0 = 177 ampere hours. Select next
larger catalog size.

2\. Calculate the ampere hour reserve of an existing 24-cell, 480-ampere
hour battery with the load increased to 69 amperes to a final voltage of
1.88 volts.

Formula: K = B/C

Where

K = 8-hour ampere hour capacity required for

each ampere of load.

B = Ampere hour capacity of existing battery.

C = Actual current drain of all equipment.

K = 480/69 = 7.0

On the chart, locate 7.0 in the 1.88-volt column

and to the left read 5 hours of reserve.

FIGURE 8 CHARGER CAPACITY

The battery charger has to supply power for operation of the COE. Its
capacity should be great enough to carry the entire load, including peak
power requirements, to avoid taking power from the battery. Additional
capacity is required to recharge the battery after a power service
interruption.

[EXAMPLE]{.underline}:

Drain 66 Amps

Battery Discharged for 3 Hours and Recharged

in 12 Hours: 3 x 66 / 12 = 16.5 Amps

Calculated Charger DC Current Requirement 82.5 Amps

Rated Charger Capacity (as indicated in

Paragraph 3.4) 75 Amps

The charger capacity sizes commercially available include:

2 @ 75 Amps - Traditional arrangement with

load sharing between the two

chargers.

3 @ 50 Amps - Potential cost saving over

buying two larger units.

Potential operating cost

saving by operating only

two units.