ADC PowerWorx User Manual
ADCP-80-575
December 2006
PowerWorx® Power Distribution Products
Select Series™ Fuse Platform (With
Enhanced KLM Fuses) User Manual
Issue 2
18858-A
1388844 Rev B
ADCP-80-575 • Issue 2 • December 2006 • Preface
COPYRIGHT
© 2006, ADC Telecommunications, Inc.
All Rights Reserved
Printed in the U.S.A.
REVISION HISTORY
ISSUE DATE REASON FOR CHANGE
1 11/2006 Original.
2 12/2006 Figure 3 block diagram changed to show dual bus; minor changes in section 1.8 and table 1.
TRADEMARK INFORMATION
PowerWorx is a registered trademark of ADC Telecommunications, Inc.
ADC is a trademark of ADC Telecommunications, Inc.
DISCLAIMER OF LIABILITY
Contents herein are current as of the date of publication. ADC reserves the right to change the contents without prior notice. In no
event shall ADC be liable for any damages resulting from loss of data, loss of use, or loss of profits and ADC further
disclaims any and all liability for indirect, incidental, special, consequential or other similar damages. This disclaimer of
liability applies to all products, publications and services during and after the warranty period.
This publication may be verified at any time by contacting ADC’s Technical Assistance Center at 1-800-366-3891, extension 73475
(in U.S.A. or Canada) or 952-917-3475 (outside U.S.A. and Canada), or by e-mail to connectivity_tac@adc.com.
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ADC Telecommunications, Inc.
P.O. Box 1101, Minneapolis, Minnesota 55440-1101
In U.S.A. and Canada: 1-800-366-3891
Outside U.S.A. and Canada: (952) 938-8080
Fax: (952) 917-1717
TABLE OF CONTENTS
Content Page
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Standards Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Admonishments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
General Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
1 PRODUCT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Product Functions and Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Fuse Platform Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Product Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Packaged Hardware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 Power Buses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.8 Bus Capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.9 Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.10 Input Power Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.11 Output Power Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.12 Ground Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.13 Alarm Contact Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.14 Alarm Contact Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.15 Fuse Alarm Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.16 Power-On Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.17 Fused Equipment Designation Card and Holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.18 Voltage Designation Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.19 Environmental Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.20 Material and Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.21 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.22 Protective Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.23 Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.24 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 UNPACKING AND INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 PRE-INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.1 General Installation Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2 Installation Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3 Materials Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4 Continuity Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 Installing Cable Management Bar (Optional Item) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2 Mounting Fuse Platform on Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3 Grounding Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4 Connecting Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.5 Connecting Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
ADCP-80-575 • Issue 2 • December 2006 • Preface
© 2006, ADC Telecommunications, Inc.
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ADCP-80-575 • Issue 2 • December 2006 • Preface
TABLE OF CONTENTS
Content Page
4.6 Connecting Input Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.7 Installing Protective Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.8 Installing GMT Fuse Designation Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.9 Installing Fuse Designation Card Holder and Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.10 Installing Voltage Designation Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5 SYSTEM CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.1 Wiring Connections Torque Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 Power On and Connection Polarity Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3 GMT Fuse Alarm Test and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.4 TPA Fuse Alarm Test and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.5 KLM Fuse Alarm Test and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.1 Clearing a KLM Fuse Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7 MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.1 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.3 Fuse Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8 CUSTOMER INFORMATION AND ASSISTANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
A APPENDIX A: ALLOWABLE AMPACITIES OF INSULATED CONDUCTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
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© 2006, ADC Telecommunications, Inc.
ABOUT THIS MANUAL
This manual describes the PowerWorx® Select Series™ Fuse Platform and provides
installation, operation, maintenance, and testing procedures. The Select Series™ Fuse Platform
is available with various types of fuses including TPA, KLM, and GMT fuses. Two types of
fuses can be combined within the same platform, if required. Within this manual, the Select
Series™ Fuse Platform is referred to as the “Select Series™ fuse platform” or the “fuse
platform”.
STANDARDS CERTIFICATION
The fuse platform complies with the applicable sections of the following standards: UL,
Telcordia, NEC 1999, CE, IEC, CSA, and NEBS Level 3.
ADMONISHMENTS
Important safety admonishments are used throughout this manual to warn of possible hazards to
persons or equipment. An admonishment identifies a possible hazard and then explains what
may happen if the hazard is not avoided. The admonishments — in the form of Dangers,
Warnings, and Cautions — must be followed at all times. These warnings are flagged by use of
the triangular alert icon (seen below), and are listed in descending order of severity of injury or
damage and likelihood of occurrence.
ADCP-80-575 • Issue 2 • December 2006 • Preface
Danger: Danger is used to indicate the presence of a hazard that will cause severe personal
injury, death, or substantial property damage if the hazard is not avoided.
Warn ing: Warning is used to indicate the presence of a hazard that can cause severe personal
injury, death, or substantial property damage if the hazard is not avoided.
Caution: Caution is used to indicate the presence of a hazard that will or can cause minor
personal injury or property damage if the hazard is not avoided.
GENERAL SAFETY PRECAUTIONS
-
Warn ing: The fuse platform uses electrical voltage and current levels that may be considered
an electrical hazard. Care should be exercised to assure that only qualified personnel are
allowed to install, operate, maintain, or otherwise come into contact with this equipment when
the fuse platform is energized. Only insulated tools should be used on energized elements of the
fuse platform.
Caution: All fuse platform wiring and cabling should be connected with the system office
battery input off or disconnected at the office distribution panel.
Caution: A replacement fuse must be of the same type and current rating as the fuse being
replaced.
© 2006, ADC Telecommunications, Inc.
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ADCP-80-575 • Issue 2 • December 2006 • Preface
Warn ing: Wet conditions increase the potential for receiving an electrical shock when
installing or using electrically-powered equipment. To prevent electrical shock, never install or
use electrical equipment in a wet location or during a lightning storm.
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© 2006, ADC Telecommunications, Inc.
1 PRODUCT DESCRIPTION
This section describes the PowerWorx Select Series Fuse Platform.
1.1 Product Functions and Features
The Select Series Fuse Platform, shown on the front cover of this manual, supplies protected dc
power to the –24 Vdc or –48 Vdc equipment typically installed in a central office, multimedia
headend, remote site, Controlled Environmental Vault (CEV), or other restricted locations. The
fuse platform is available in a single or dual bus configuration and in several configurations of
fuse types. The fuse platform provides the following important features:
• 19-inch or 23-inch EIA or WECO rack mounting.
• Self-configuring input voltage capability to –24 Vdc or –48 Vdc.
• GMT, KLM, or TPA fuse types alone (with corresponding fuse holder modules), or GMT
in combination with either of the other two types.
Note: KTK fuses will also fit in the KLM fuse holder, but are not currently rated for dc
voltages by Underwriters Laboratories (UL).
ADCP-80-575 • Issue 2 • December 2006
• “Upside down” GMT fuse holders making blown fuses easier to see.
• Optimally-positioned, high-brilliance fuse alarm (red LED) indicators, providing quick
identification of blown fuses.
Note: For KLM fuses, there is a two-color (green/red) LED for each fuse position. A
green LED indicates a good fuse. A red LED indicates a failed fuse or a removed fuse. A
method is available to disable the LED (no green or red light) when a fuse holder is left
empty on purpose (see Section 6.1 on Page 28).
• Field-replaceable high-brilliance power-on (green LED) indicators (one per bus).
• Easy-to-remove plastic protective covers for input and output terminals.
• Two-hole compression-lug terminals for input power connections.
• Two grounding studs for robust and reliable ground connectivity.
• Screw-down barrier terminal strips for power output connections.
• Relay contacts for alarms (corresponding to red LEDs above). The alarm contacts may be
used to open or close a loop connected from an external alarm system.
1.2 Fuse Platform Components
The Select Series Fuse Platform, shown in Figure 1, is a customer-configurable product
containing either one or two power buses. Each power bus is connected to multiple fuse holder
modules. In a dual bus platform, the two buses are mirror images of one another, having the
same types of fuses and the same size fuse holder modules.
© 2006, ADC Telecommunications, Inc.
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ADCP-80-575 • Issue 2 • December 2006
UL/CSA/CE
LABEL
BUS A POWER ON
INDICATOR
(GREEN LED)
BUS B POWER ON
INDICATOR
(GREEN LED)
BUS A KLM/KTK
FUSE HOLDERS
BUS B
POWER INPUT
TERMINALS
BUS B
KLM/KTK FUSED
POWER OUTPUT
TERMINALS
FUSE ALARM
INDICATOR
(TYPICAL)
FUSE HOLDER
(4 POSITION)
FRONT VIEW
BUS B
GMT FUSED
POWER OUTPUT
TERMINALS
BUS A
KLM/KTK
BUS A GMT
ALARM
TERMINALS
BUS A GMT
FUSE ALARM
INDICATOR
BUS B GMT
FUSE HOLDER
(4 POSITION)
BUS A
GMT FUSED
POWER OUTPUT
TERMINALS
KLM/KTK FUSED
POWER OUTPUT
BUS B GMT
FUSE ALARM
INDICATOR
CHASSIS
GROUND
STUDS
BUS A
TERMINALS
BUS B KLM/KTK
FUSE HOLDER
BUS A
POWER INPUT
TERMINALS
BUS B
KLM/KTK
FUSE ALARM
INDICATOR
(TYPICAL)
DESIGNATION CARD
AND CARD HOLDER
MOUNTING
BRACKETS (2),
INSTALLED FOR 19-IN.
(48.26 CM) RACK
MOUNTING
REAR VIEW
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© 2006, ADC Telecommunications, Inc.
PROTECTIVE
COVER
Figure 1. Dual Bus KLM-GMT Fuse Platform
COVERS FOR
INPUT POWER
TERMINALS
18877-B
Warn ing: Use of one bus only on a dual bus panel will result in false alarms for the unused bus.
Power is required on both buses on a dual bus panel for normal operation.
Depending on customer order, the fuse platform may have one fuse type alone, or GMT fuses in
combination with one other fuse type (KLM or TPA). The number of fuse positions on each bus
is dependent on the maximum current limit, as well as on the current value of the fuses and the
width of the fuse holders. The maximum current input per bus is 100 Amps.
Note: The continuous output load of the equipment during normal operation should not
exceed 80% of the rated value of the fuse. This allows some room for manufacturing
tolerances and voltage fluctuations in the plant power mains.
Figure 1 shows the external features of a typical fuse platform (in this case, a dual bus fuse
platform with four KLM and four GMT fuses per bus).
1.3 Product Options
ADCP-80-575 • Issue 2 • December 2006
The following configurations of fuses are available:
• Four TPA fuses with four or ten GMT fuses
• Two or four KLM or KTK fuses with four or ten GMT fuses
• Any of the above fuse types alone including:
– Four TPA fuses per bus
– Two or four KLM or KTK fuses per bus
– Ten GMT fuses per bus
Fuse capacity varies per fuse type (see Section 1.8, Bus Capacity on page 8). The total fuse
output cannot exceed 100 Amps per bus (200 Amps per dual bus platform).
Note: The continuous output load of the equipment during normal operation should not
exceed 80% of the rated value of the fuse. This allows some room for manufacturing
tolerances and voltage fluctuations in the plant power mains.
All fuse platforms have power-on LEDs that light in green indicating the presence of power and
fuse alarm LEDs that light in red indicating a blown fuse. In addition, the fuse alarm LEDs on
the enhanced KLM fuse platform have a green state indicating that a fuse is installed and
receiving power.
Two types of alarm contacts are available: wire wrap or screw-down barrier terminal strip.
Two fuse platform mounting options are available: EIA/WECO or ETSI. (All fuse platforms can
be installed in either a 19-inch or 23-inch rack. The fuse platform comes with mounting
brackets for both rack widths.)
© 2006, ADC Telecommunications, Inc.
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ADCP-80-575 • Issue 2 • December 2006
1.4 Packaged Hardware
The fuse platform is shipped with hardware components (shown in Figure 2) that are packaged
separately and enclosed in the same carton. The packaged hardware components include the
following items:
• Two sets of mounting brackets (for 19-inch or 23-inch rack mounting)—Used to mount
the panel on the equipment rack.
• 5/16-inch long, Phillips drive, 8-32 flat-head thread-forming screws (8)—Used to secure
the mounting brackets to the panel.
• 3/8-inch long, combination drive, 12-24 pan-head screws (4) and #12 flat washers (4)—
Used to secure the mounting brackets to the equipment rack.
• #10 ring terminals (2) for 12–10 AWG wire—Used to connect the grounding cables to the
grounding studs.
• Rear protective input terminal covers and output terminal covers—Used to prevent
accidental contact with the power input and output terminals. The number of covers
provided depends on the fuse configuration.
• Designation card and card holder—Used to record information about the protected
equipment. The card holder has a pressure-sensitive adhesive backing to permit
attachment to the panel, the rack, or a location close to the panel. The designation card
inserts into the card holder. It is also available as an accessory item.
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© 2006, ADC Telecommunications, Inc.
REAR COVER FOR OUTPUT POWER TERMINAL BLOCKS,
ALARM TERMINALS, AND CHASSIS GROUND TERMINALS
ADCP-80-575 • Issue 2 • December 2006
REAR COVERS FOR INPUT
POWER TERMINAL BLOCKS
DESIGNATION CARD,
PROTECTIVE COVER,
AND CARD HOLDER
#10 RING TERMINALS FOR
12-10 AWG WIRE (GROUNDING)
5/16-INCH (7.936 MM) 8-32
FLAT-HEAD SCREWS
19-INCH
RACK MOUNTING
BRACKETS
3/8-INCH (9.525 MM) 12-24
SCREWS AND #12 WASHERS
23-INCH
RACK MOUNTING
BRACKETS
MOUNTING BRACKETS
AND SCREWS FOR 19-INCH OR
23-INCH RACK INSTALLATION
18876-A
Figure 2. Packaged Hardware Components
© 2006, ADC Telecommunications, Inc.
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ADCP-80-575 • Issue 2 • December 2006
1.5 Accessories
The following accessories are available for the fuse platform:
• Standard size GMT, KLM, and TPA type fuses
• GMT colored fuse-value designation pins (rivets)
• Cable management bar kits
• GMT fuse pullers
• Two-hole compression connector lugs for input power connections
• Lug terminals to connect #10 AWG wire to earth ground
• GMT fuse value designation pin holders
• Fuse value designation card holder kits
1.6 Mounting
The fuse platform can be mounted in a 19-inch (48.26 cm) or a 23-inch (58.42 cm) equipment
rack. Two pairs of mounting brackets, one pair for 19-inch racks and one pair for 23-inch racks,
are provided with the fuse platform. The fuse platform can be flush mounted or recessed 1, 2, 3,
or 4 inches (2.54, 5.08, 7.62 or 10.16 cm) from the front of the rack. The mounting brackets
allow mounting in racks with WECO 1.00-inch (2.54 cm) hole spacing or EIA 1.25-inch (3.18
cm) hole spacing. The slotted hole pattern in the mounting brackets compensates for vertical
rack differences and allows the fuse platform to be mounted in either 1.75- or 2-inch (4.45 or
5.08 cm) rack spaces.
1.7 Power Buses
The fuse platform is available with one or two separate power buses. Each bus distributes the
input power to multiple fused output circuits. In each bus circuit, current flows from the input
connector to the fuse bus. When a fuse is installed in a fuse holder, the circuit is completed to
the corresponding output connector. Figure 3 provides a block diagram of the power buses in a
typical fuse platform (dual bus model shown).
Fuse failure is sensed by a sensor which causes the alarm monitor to light a red LED indicator
on the front of the fuse holder. The function of the fuse failure indicator differs depending on
fuse type as follows:
• For GMT fuses, there is a red LED indicator for each set of fuses (depending on product
configuration, each fuse holder holds four or ten fuses). Fuse failure also opens and closes
a set of alarm contacts (form C dry contacts) connected to the alarm output terminals.
There is one such set of alarm contacts for each bus, with failure of any fuse on the bus
causing an alarm condition.
• For TPA fuses, there is an individual red LED indicator for each individual fuse because
each fuse holder holds a single fuse.
• For KLM fuses, there is an individual two-color indicator (green/red LED) for each fuse.
The indicator functions as follows:
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© 2006, ADC Telecommunications, Inc.
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