SM32A
VR28-013
DC/DC Power Converter
Serial Numbers 1221 and later
INSTALLATION AND OPERATION MANUAL
REV 4.00 Aug 21, 2006
Northern Airborne Technology Ltd.
1925 Kirschner Road
Kelowna, BC, Canada.
V1Y 4N7
Telephone (250) 763-2232
Facsimile (250) 762-3374
Copyright 2006 by Northern Airborne Technology
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
SM32A Rev 4.00 VR28-013 DC/DC Power Converter Manual
Periodically NAT will release manual amendments. In order to maintain the most
accurate and up to date manual these amendments should be carried out immediately
upon receipt and recorded on the following amendment record.
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Note: Revision 4.00 is the first public release of this document
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Aug 21, 2006 Page ii
ENG-FORM: 820-0110.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
SM32A Rev 4.00 VR28-013 DC/DC Power Converter Manual
Table of Contents
Section Title Page
1 Description
1.1 Introduction 1-1
1.2 Purpose of Equipment 1-1
1.3 Features 1-1
1.4 Specifications 1-1
1.4.1 Electrical Specifications 1-1
1.4.2 Physical Specifications 1-2
1.4.3 Miscellaneous Specifications 1-3
1.4.4 Environmental Specifications 1-3
2 Installation
2.1 Introduction 2-1
2.2 Unpacking and Inspection 2-1
2.2.1 Warranty 2-1
2.3 Installation Procedures 2-1
2.3.1 Warnings 2-1
2.3.2 Cautions 2-1
2.3.3 Cabling and Wiring 2-2
2.3.4 Post-Installation Checks 2-2
2.4 Continued Airworthiness 2-3
2.5 Accessories Required But Not Supplied 2-3
2.6 Installation Drawings 2-3
3 Operation
3.1 Introduction 3-1
3.2 General 3-1
3.3 Operation Specifics 3-1
Aug 21, 2006 Page iii
ENG-FORM: 820-0110.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
SM32A Rev 4.00 VR28-013 DC/DC Power Converter Manual
Section 1 Description
1.1 Introduction
This manual contains information on the VR28-013 DC/DC Power Converter (serial
numbers 1221 and later). All derivative products will be covered by manual
supplements, which can be obtained from NAT as required.
Information in this section consists of purpose of equipment, features and specifications.
1.2 Purpose of Equipment
The VR28-013 is an efficient voltage converter designed to power non-aircraft radios or
equipment from a 28 Vdc aircraft power buss. It is a remote bulkhead mounted unit
designed to convert a nominal +28 Vdc input to a nominal +13 Vdc output at up to 6 Amps.
1.3 Features
The VR28-013 uses the same switched-mode power supply (SMPS) circuitry utilized by
NT-series radios to provide constant output power without excessive heat generation.
The unit has remote on/off switching.
An output power LED is provided to give a visual indication that the unit is operating.
Power In, Power Out, and Ground pins are grouped together and internally connected
for installation versatility.
The unit has over-voltage and reverse-voltage protection to ensure operation in severe
aircraft environments.
1.4 Specifications
1.4.1 Electrical Specifications
Power Supply: Switched-mode regulated power supply with input reverse-polarity, over-
current, over-voltage, and output short-circuit protection.
Operating Voltages
Nominal +28.0 Vdc
Minimum +22.0 Vdc
Maximum +30.3 Vdc
Emergency +18.0 Vdc
Aug 21, 2006 Page 1-1
ENG-FORM: 800-0108.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
VR28-013 DC/DC Power Converter Manual SM32A Rev 4.00
Current Consumption
Standby 0.03 A nom. (Off)
No Load 0.1 A nom. (@ I
Low Current Load 0.5 A nom. (@ I
0.8 A nom. (@ I
High Current Load 2.0 A nom. (@ I
4.0 A nom. (@ I
=0.0 A)
OUT
=0.6 A)
OUT
=1.2 A)
OUT
=3.0 A)
OUT
=6.0 A)
OUT
Power Output
Intermittent Operation +13.0 Vdc ±10%, 6.0 A max.
Continuous operation +13.0 Vdc ±10%, 20% duty cycle:
1 minute at I
4 minutes at I
=6.0 A,
OUT
OUT
=1.2 A
Efficiency 80% typical
Input Overcurrent Protection Internal Fuse, 7 A capacity
Input Signals
Power On/Off: Voltage: <1 Vdc (logic LO) for ON
Current: 15 mA nom., sink
Output Signals N/A
1.4.2 Physical Specifications
Height 1.85" (47.0 mm) max
Depth 5.32" (135.1 mm) max
Width 3.99" (101.3 mm) max
Weight 1.02 lbs (0.46 kg) max
Mounting Remote bulkhead mount with four 10-32 screws
Material/Finish:
Chassis and cover Brushed aluminum with chromate conversion finish
Heatsink Aluminum extrusion with clear anodized finish
Connectors: J3 Male 15 pin D-submin connector with jackposts
Page 1-2 Aug 21, 2006
ENG-FORM: 800-0108.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.