Nautel NX15 User manual

NX15/NX25 Transmitter
Operations and Maintenance
Manual
Document:NHB-NX15-NX25-OPS
Issue: 6.0 2019-01-31
Status: Standard

Nautel Limited
10089 Peggy’s Cove Road
Hackett’s Cove, NS Canada B3Z 3J4
Phone: [phone] or
Toll Free: +1.877.6NAUTEL (6628835) (Canada & USA only)
Fax: [phone]
Nautel Inc.
201 Target Industrial Circle
Bangor, Maine USA 04401
Phone: [phone]
Fax: [phone]
Customer Service (24 hour support)
+1.877.628.8353 (Canada & USA only)
+1.902.823.5100 (International)
Email: [email protected]
Web: www.nautel.com
The comparisons and other information provided in this document
have been prepared in good faith based on publicly available
information. The reader is encouraged to consult the respective
manufacturer's most recent published data for verification.
© Copyright 2019 NAUTEL. All rights reserved.

NX15/NX25 Operations and Maintenance Manual Table of contents
Page v
Contents
Release control record vii
Description 1-1
Ac-Dc Power Stage 1-2
Exciter Stage 1-4
Control/Monitor Stage 1-7
RF Power Stage 1-8
RF Output Network 1-9
Operating the transmitter 2-1
Using the AUI 2-2
Home page - describing the first page 2-19
Menu page - describing transmitter operations 2-20
Viewing Transmitter Log 2-22
Instrument Panels - viewing displays 2-29
Meters page - viewing real-time meters 2-45
Presets - editing operational settings 2-51
Preset Scheduler 2-67
Status - viewing transmitter status 2-72
User Accounts 2-74
User Settings 2-79
System Settings page 2-97
Precorrection Settings page 2-106
Changeover page - changing exciter transfer settings 2-115
Factory Settings 2-116
Remote I/O page 2-125
Audio Player 2-131
Using the ac disconnect switch 2-135

NX15/NX25 Operations and Maintenance Manual
Page vi Issue 6.0 2019-01-31
Using the Keyed Controlled Access System (optional) 2-138
Routine maintenance 3-1
Scheduled maintenance 3-1
Replacing the air filter 3-2
Performing on-air checks 3-4
Replacing the Control/Interface PWB battery 3-6
Inspecting lightning protection systems 3-7
Non-standard maintenance 4-1
Upgrading software 4-1
Updating or Replacing Compact Flash Card 4-4
List of terms 5-1

NX15/NX25 Operations and Maintenance Manual
Issue 6.0 2019-01-31 Page vii
Release control record
Issue Date Reason
6.0 2019-04-01 Supports hardware NARA59D and software version
NX SW 4.7 or higher.

NX15/NX25 Operations and Maintenance Manual
Page viii Issue 6.0 2019-01-31

NX15/NX25 Operations and Maintenance Manual Description
Issue 6.0 2019-01-31 Page 1-1
Section 1: Description
This section provides a high-level description of the transmitter’s key sections. The transmitter
circuitry is subdivided into five basic stages.
•Ac-Dc Power Stage
•Exciter Stage - see page 1-4
•Control/Monitor Stage - see page 1-7
•RF Power Stage - see page 1-8
•RF Output Network - see page 1-9 (includes combiner and filter)
Refer to the functional block diagram: see Figure 1.6 on page 1-15.
NX15/NX25 Electrical Schematics
Some descriptions in this section refer to electrical schematics (SD-#s). These are located at the
end of the NX15/NX25 Troubleshooting Manual.
Redundancy
The NX15/NX25 features redundancy in all key systems:
• RF power modules
•Exciters
• Cooling fans
• Low voltage power supplies

NX15/NX25 Operations and Maintenance Manual Description
Page 1-2 Issue 6.0 2019-01-31
Ac-Dc Power Stage
See electrical schematic SD-1. The ac/dc power supply stage contains the input power
transformer that receives the main ac input to the transmitter. It also contains the transmitter’s
low voltage power supplies and rack interface PWB. The ac/dc power supply stage also
includes a three-phase SCR rectifier assembly, B+ current sensor, B+ distribution assembly,
capacitor tray assembly and arc detector assembly.
Ac Power Transformer
The NX15/NX25’s power transformer can be set to use a range of input voltages. See Section
3, “Installing the power transformer” on page 3-1 in the NX15/NX25 Installation Manual.
High Voltage B+ Power Supply
The secondary of the power transformer is applied to the SCR rectifier assembly to create the
transmitter’s B+ voltage (normally 400 Vdc). The output of the rectifier assembly is fed
through the B+ current sensor, which supplies a B+ current sample to the rack interface PWB.
The rectifier assembly output is applied to a choke input filter and the B+ distribution
assembly, which then provide the B+ voltage to the RF power modules.
The B+ discharge relay, which is part of the capacitor assembly, opens when ac power is
applied and closes and ac power is removed, applying a high power discharge resistor across the
B+ bus to quickly discharge the voltage. When the discharge relay closes, a microswitch
ensures the SCR rectifier is immediately inhibited.
Low Voltage Power Supplies
One phase of the power transformer’s secondary is also used to provide a source for the low
voltage dc power supplies and an ac sample for the rack interface PWB. The low voltage power
supply outputs (+48 V, +15 V and +12 V) are distributed throughout the transmitter via the
rack interface PWB. The +48 V power supply sources the transmitter’s cooling fans. An
inhibit signal, controlled by the rack interface PWB, is applied to the +48 V power supply to
turn the fans on and off. The +15 V power supply sources all of the low voltage control
circuitry. The +12V power supply sources the SBC and the touchscreen monitor.