Bird Technologies 8640B User Manual

INSTRUCTION BOOK

MODULOAD® RF LOAD RESISTOR

SERIES 8640 and 8640B

INCLUDING MODELS 8645-xxx AND 8646-xxx

Bird® Electronic Corporation
30303 Aurora Road
Cleveland (Solon), Ohio 44139

Sales & Technical Support: 440-248-1200

Sales email: [e-mail]
Technical Support email: [e-mail]

Moduload

866-695-4569 toll free

©Copyright 2008 by Bird Electronic Corporation

Instruction Book Part Number 920-8640S Rev. F

®

, Econoload®, Econoline®, and Thruline® are

registered trademarks of Bird Electronic Corporation

Safety Precautions

The following are general safety precautions that are not necessarily
related to any specific part or procedure and do not necessarily appear
elsewhere in this publication. These precautions must be thoroughly
understood and applied to all phases of operation and maintenance.

Keep Away From Live Circuits

Operating personnel must at all times observe normal safety regulations.
Do not replace components or make adjustments inside the equipment
with high voltage turned on. To avoid casualties, always remove power.

Shock Hazard

Do not remove the RF transmission line while RF power is present.

Capacitors can store a dangerous electric charge. Avoid contact with all
system capacitors. If it is necessary to perform work near a system
capacitor, be sure to discharge the capacitor through a low resistance.

Do Not Service Or Adjust Alone

Under no circumstances should any personnel reach into an enclosure for
the purpose of service or adjustment of equipment except in the presence
of someone who is capable of rendering aid.

Safety Earth Ground

An uninterruptible earth safety ground must be supplied from the main
power source to test instruments. Grounding one conductor of a two
conductor power cable is not sufficient protection. Serious injury or death
can occur if this grounding is not properly supplied.

Chemical Hazard

Dry cleaning solvents for cleaning parts may be potentially dangerous.
Avoid inhalation of fumes or prolonged contact with skin.

Coolant may contain ethylene glycol. Avoid ingestion, inhaling of vapors
and eye and skin contact.

Resuscitation

Personnel working with or near high voltages should be familiar with
modern methods of resuscitation.

i

Bird 8640 and 8640B Series Moduload RF Load Resistor

Safety Symbols

WARNING

Warning notes call attention to a procedure, which if not correctly

performed could result in personal injury.

CAUTION

Caution notes call attention to a procedure, which if not correctly

performed could result in damage to the instrument.

This symbol indicates that a shock hazard exists if the
precautions in the instruction manual are not follwed.

The caution symbol appears on the equipment indicating
there is important information in the instruction manual
regarding that particular area.

 NOTE: Calls attention to supplemental information.

Warning Statements

The following safety warnings appear in the text where there is danger to
operating and maintenance personnel and are repeated here for emphasis.

WARNING

Disconnect the unit from all power sources before servicing.

The unit may be energized from multiple sources.

The potential for electric shock exists.

WARNING

Improper wiring could result in electric shock and death.

WARNING

Connect the power cord to the Moduload

BEFORE connecting to ac mains.

WARNING

Ethylene glycol is toxic. Do not take internally.

Avoid contact with eyes, skin, and clothing. Avoid breathing vapor.

Wash thoroughly after handling.

ii

WARNING

Never attempt to connect or disconnect RF equipment from the

transmission line while RF power is being applied.

Leaking RF energy is a potential health hazard.

WARNING

HEAVY. Do not lift this unit alone.

Caution Statements

The following equipment cautions appear in the text whenever the
equipment is in danger of damage and are repeated here for emphasis.

CAUTION

Do not block air flow. The air intake vents on the side of the heat

exchanger and the exhaust on top must not be obstructed.

CAUTION

Do not operate without the interlock. Even momentary

application of RF power while coolant is not circulating could

cause immediate destruction of the load.

CAUTION

Check the local electrical code for proper ac hookup prior to operation

of the unit. Make sure the neutral or return hookup is only used

for that purpose.

CAUTION

Use only distilled water or ethylene glycol as coolant. Do not use tap

water, automotive antifreeze, sealants, or leak stopping material.

Use of these materials will damage the unit and void all warranties.

CAUTION

Operation without sufficient coolant can damage the unit.

iii

Bird 8640 and 8640B Series Moduload RF Load Resistor

Safety Statements

USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT

SPECIFIED BY THE MANUFACTURER MAY IMPAIR THE

INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA

POR EL FABRICANTE, PUEDE ANULAR LA PROTECCIÓN DE
SEGURIDAD DEL INSTRUMENTO.

BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM

HERSTELLER BESCHRIEBEN, KANN DIE GERÄTESICHERHEIT
BEEINTRÄCHTIGT WERDEN.

UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS

EXPLICITEMENT PRÉVUE PAR LE FABRICANT PEUT
ENDOMMAGER LE DISPOSITIF DE PROTECTION DE
L’INSTRUMENT.

IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO

DIVERSO DA COME SPECIFICATO DAL PRODUTTORE LA
PROZIONE DI SICUREZZA POTREBBE VENIRNE COMPROMESSA.

SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE -

TRAINED PERSONNEL ONLY. TO AVOID DANGEROUS
ELECTRIC SHOCK, DO NOT PERFORM ANY SERVICING UNLESS
QUALIFIED TO DO SO.

SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO

DEL PERSONAL DE SERVICIO CAPACITADO. PARA EVITAR EL
PELIGRO DE DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN
SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA HACERIO.

WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR

FÜR GESCHULTES FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS,

SIND WARTUNGSARBEITEN AUSSCHLIEßLICH VON
QUALIFIZIERTEM SERVICEPERSONAL DURCHZUFÜHREN.

iv

ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE

RÉSERVÉ AU PERSONNEL FORMÉ AUX OPÉRATIONS
D’ENTRETIEN. POUR PRÉVENIR UN CHOC ÉLECTRIQUE
DANGEREUX, NE PAS EFFECTUER D’ENTRETIEN SI L’ON N’A PAS
ÉTÉ QUALIFIÉ POUR CE FAIRE.

ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE

ESCLUSIVAMENTE PER IL PERSONALE OPPORTUNAMENTE
ADDESTRATO. PER EVITARE PERICOLOSE SCOSSE ELETTRICHE
NON EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE
QUALIFICATI A FARLA.

CONNECT INTERLOCK TO TRANSMITTER/GENERATOR/
AMPLIFIER BEFORE OPERATING.

BRANCHER LE VERROUILLAGE À L’ÉMETTEUR/

GÉNÉRATEUR/AMPLIFICATEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR/GENERADOR/

AMPLIFICADOR ANTES DE LA OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER/

GENERATOR/VERSTÄRKER ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L’APPARECCHIO, COLLEGARE

IL DISPOSITIVO DI BLOCCO AL TRASMETTITORE/GENERATORE/
AMPLIFICATORE.

v

Bird 8640 and 8640B Series Moduload RF Load Resistor

About This Manual

This manual covers the Bird 8645B and 8646B Moduload RF Load
Resistors.

This instruction book is arranged so that essential information on safety
is in the front of the book. Reading the Safety Precautions before
operating the equipment is strongly advised. The remainder of this
instruction book is divided into Chapters and Sections.

Operation

First time operators should read Chapter 1 - Introduction, and Chapter 3

- Installation, to get an overview of equipment capabilities and how to
install it. An experienced operator can refer to Chapter 4 - Operating
Instructions. All instructions necessary to operate the equipment are
contained in this chapter.

Maintenance

All personnel should be familiar with preventative maintenance found in
Chapter 5 - Maintenance. If a failure should occur, the troubleshooting
section will aid in isolating and repairing the failure. Parts lists and
repair instructions are also in this chapter.

Changes To The Manual

We have made every effort to ensure this manual is accurate at the time
of publication. If you should discover any errors or if you have suggestions
for improving this manual, please send your comment to our factory. This
manual may be periodically updated. When inquiring about updates to
this manual, refer to the part number and revision level on the title page.

Naming Conventions

The following terms will be used throughout this manual to refer to
certain components of the Moduload:

Moduload: The entire unit.
Load: The component which connects to the RF line. It is inside the HEAT

EXCHANGER, connected by two hoses. It contains the RESISTOR.
Heat Exchanger: The parts of the Moduload left when the LOAD is

removed. It contains the pump, fans, coolant reservoir, and controls.

vi

Resistor: A subcomponent of the LOAD. This is the ceramic resistor
which actually absorbs the RF power.

vii

Table of Contents

Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Moduload Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Items Required but not Supplied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Optional Items Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Flow Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Thermal Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Unpacking and Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Placement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Meter Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Interlock Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

AC Mains Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Adding Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Connecting RF Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . 11

Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Emergency Shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

viii

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Changing Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Coolant Flush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Interlock Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Flow Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Load Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Pump Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Resistor Servicing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Resistor Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Fractured Resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Resistor Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Conductor Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Preparation for Storage or Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

ix

x

Chapter 1 Introduction

Bird 8640 and 8640B Series Moduloads are self-cooling, nonradiating,
low reflection terminations for high power RF lines. They dissipate up
to 25 kW with a VSWR of less than 1.1:1 from 1 kHz to 900 MHz.

The Moduload has an interlock which triggers as a result of either
high coolant temperature or low coolant flow. It will also be active for
about 2 seconds after power up or reset to ensure proper operation of
the cooling system before applying RF power.

Moduload

Features

y Useable with CW, AM, FM, SSB, and TV modulation, and certain

pulse types. Contact Bird Electronic Corporation for information
on using Moduloads with pulsed signals.

y Useable to make RF power measurements when used with a Bird

4600 or 4800 Thruline Wattmeter

y Self-contained water-based cooling system
y Time-delay interlock ensures steady coolant flow before RF power

is applied

Indicators y Coolant Level Gauge

Items Supplied y Moduload

y Instruction Manual
y Power Meter Rack-Mount Kit

Items Required but

not Supplied

y No. 22 AWG wire, with ring terminals, for interlock connection
y RF Coupling Kit
y Ethylene Glycol, Industrial Grade, 1 Gallon - available from Bird

Optional Items

Available

y Dolly (Bird P/N 6771-011) for moving the load

1

Bird 8640 Series Moduload RF Load Resistor

AC ON

INTERLOCK

19.25”

(490 mm)

9.75”

(248 mm)

9.875”

(251 mm)

19.625”

(500 mm)

26”

(660 mm)

Coolant

Reservoir

Pump

Load

Resistor

RF

Input

Flow

Switch

Temperature

Switch

Fan

Fan

Heat Exchanger

Heat Exchanger

Figure 1

8640 Series Moduload

Outline Drawing

Figure 2

System Block

Diagram

2

Chapter 2 Theory of Operation

Resistor Bird 8640 and 8640B Series Moduloads consist of a thin-film-on-

ceramic resistor immersed in coolant. The coolant flows directly over
the resistor instead of using an intermediate heat transfer system,
reducing the load size to a minimum. After passing over the entire
length of the resistor, the coolant is cooled in a forced air heat
exchanger.

Coolant The load’s electrical and thermal performance is reduced by

impurities or chemical additives in the coolant, especially ones which
are deposited as scale on the resistor. This increase in the load’s
thermal resistance may cause the load to overheat and fail. Therefore,
the coolant should be distilled water or a mixture of distilled water
and ethylene glycol.

When the coolant is heated, thermal expansion causes an increase in
the internal pressure. The vent plugs relieves this pressure while
protecting the opening from dirt or other contaminants.

Flow Interlock Dissipation of the heat generated by RF power is critically dependent

on a minimum coolant flow of six gallons per minute at all times,
regardless of coolant temperature. When coolant flow drops below six
gallons per minute, the low flow switch opens causing immediate
transmitter shutdown. The flow switch is a “normally open” type, and
is closed during normal operation.

After flow is restored, a time delay switch keeps the interlock open for
an additional 2 seconds. This ensures proper operation of the cooling
system before RF power is applied to the load, preventing resistor
damage or burnout.

Thermal Interlock The Moduload is equipped with a normally closed thermoswitch

which opens when the coolant temperature exceeds 79 °C (174 °F),
opening the interlock.

3