AVO 569001 User manual

Instruction Manual
AVTM56-9J Rev. A
For the
Ultrasonic Corona
and Leak Detector
Catalog Number 569001
and Accessories
P.O. BOX 9007, VALLEY FORGE, PA 19485-1007 ! 1-800-723-2861

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Instruction Manual 56-9J
for the use of
ULTRASONIC CORONA
and LEAK DETECTOR
Catalog Number 569001
AVO International
P.O. Box 9007
Valley Forge, PA 19485-1007

TABLE OF CONTENTS
FIG. 1: ULTRASONIC CORONA AND LEAK DETECTOR CAT. NO. 569001 ..a1
FIG. 2: ACCESSORY ITEMS. ...........................................................................a2
INTRODUCTION ............................................................................................... A1
SAFETY PRECAUTIONS .................................................................................. B1
RECEIVING INSTRUCTIONS ........................................................................... C1
DESCRIPTION AND SPECIFICATIONS........................................................... D1
OPERATION...................................................................................................... E1
APPLICATION ....................................................................................................F1
MAINTENANCE................................................................................................. G1
WARRANTY AND REPAIRS ............................................................................. H1

a1
FIGURE 1: ULTRASONIC CORONA AND LEAK DETECTOR CATALOG NO. 569001

a2
Contact Probe, Catalog No. 569001-8
FIGURE 2: ACCESSORY ITEMS.
Ultrasonic
Tone Generator,
Catalog No.
569001-7

A1
Section A
INTRODUCTION
Electrical discharges from a high voltage terminal to the air (corona) or along an
insulated surface generate acoustical signals. Over a wide range of
circumstances a significant portion of the generated signal energy will have
frequencies above the range of the human ear. This is the ultrasonic frequency
range and may be used to detect the presence of corona or surface discharge
with the advantage that audible background noise is excluded.
Corona and surface discharge are localized to small areas relative to the total
size of the equipment. The Biddle Cat. No. 569001 Ultrasonic Corona and Leak
Detector is equipped with a highly directional horn to permit the user to localize
the source of the electrical discharge while remaining at a safe distance from the
electrical terminals. This directional property also increases the sensitivity of the
detector and tends to exclude any ultrasonic signals not related to the test in
progress. The Cat. No. 569001 is effective in locating corona on insulators,
bushings, and potheads in energized circuits such as utility poles, non-enclosed
switchgear, bus bars or transformers and aids in isolating multiple sources
located on the equipment under test. It is also useful in checking insulation test
setups for either ac or dc to determine if corona is present on the test terminals.
Pinpointing such corona and demonstrating its reduction will usually result in
considerable saving of testing time and assist in obtaining reliable results.
The Detector is designed for easy use. It is supplied in a compact light-weight
carrying case; it operates on a single transistor battery and is quickly ready for
service in the field or on the test floor.
In addition to detecting corona sources, the Detector is an excellent tool for
locating gas leaks and other sources of ultrasound.

A2
Section A
INTRODUCTION (Cont’d.)
When ultrasound is generated in parts of a container or assembly, the surfaces
of the container usually transmit the ultrasonic sound but may not radiate
effectively. For such cases the Cat. No. 569001-8 Contact Probe accessory is
available. This probe makes direct contact with the surface to detect the
ultrasound, similar to the action of a stethoscope. The contact probe is used to
identify such problems as defective bearings or gears, or leaking steam traps.
Ultrasonics can also be used to detect leaks in a sealed container before it is
filled. (This can be a significant cost saving.) The container can be considered, in
the general sense, as any enclosure where a leak may be damaging. For such
applications, the Cat. No. 569001-7 Ultrasonic Transmitter is available. In effect,
the transmitter is sealed in the enclosure or container while it is transmitting.
Since ultrasonic sound will escape through remarkably small openings, the
detector is used to scan the outside to locate the leak.

B1
Section B
SAFETY PRECAUTIONS
SAFETY IS THE RESPONSIBILITY OF THE USER
LA SEGURIDAD ES LA RESPONSABILIDAD DEL OPERADOR
Although this test set does not contain any high voltages, it is usually operated in
the vicinity of high voltage apparatus. The Test Set must be used only by
persons fully aware of the proper safety procedure in such locations.
Further precautions are necessary because the person wearing headphones
may not hear vehicular traffic or audible alarms. When such hazards exist
BIDDLE Instruments recommends that the loudspeaker or meter of the Cat. No.
569001 be used in preference to the headphones.
The sound produced by the headphones of the Cat. No. 569001 can reach levels
approaching those that risk hearing damage, therefore, the operator must set the
volume control at a sufficiently low level to prevent discomfort.
BIDDLE Instruments considers it advisable for the user to become familiar with
the Cat. No. 569001 prior to using it in the field.

B2

C1
Section C
RECEIVING INSTRUCTIONS
When your BIDDLE instrument arrives, check the equipment received against the
packing list to ensure that all items are present. Notify AVO International Valley
Forge, PA 19485 of any shortage. Make sure all the components shown in
Figure 1 are included.
Examine the instrument for damage received in transit. If any damage is
discovered, file a claim with the carrier at once and notify BIDDLE Instruments or
its nearest authorized sales representative, giving detailed description of the
damage observed.
This instrument has been thoroughly tested and inspected to meet rigid
inspection specifications before being shipped. It is ready for use when set up as
indicated in Section E.

C2

D1
Section D
DESCRIPTION and SPECIFICATIONS
GENERAL
The Biddle Cat. No. 569001 Detector consists of several interconnecting
components supplied in a cushioned carrying case as shown in Figure 1. The
microphone probe and the receiver make up a basic complete system. The
receiver converts and amplifies the ultrasonic signals from the microphone probe
to an audible loudspeaker or headphone output and also to a meter deflection. It
has a single control for on-off and volume.
Although the microphone probe has directional properties, a great improvement
is provided by assembling it into the directional “horn” which is the key part of the
system. The horn focuses sharply enough to enable the user to locate corona
sources while remaining at a safe distance from the high-voltage energized
apparatus. A pistol-grip holder and a peepsight provide for aiming.
A rubber “sound concentrator” tube can also be attached to the microphone; this
aids in locating very small ultrasound emitters of mechanical nature such as
pinhole gas leaks.
Two accessories are available for use with the basic detector, (see Fig. a2). One
is a contact probe that replaces the microphone. When this is used, the detector
acts similar to a stethoscope to detect ultrasound transmitted in solid bodies. The
second accessory is an ultrasound Tone Generator; an independent unit that can
be placed in an enclosure. The ultrasound generated will penetrate small
openings and can be detected using the microphone pickup with the detector.
CIRCUIT DESCRIPTION
The solid state circuit operates on the hetrodyne (heat frequency) principle. The
detecting microphone probe is crystal responsive to frequencies from about 35 to
45 kilohertz.
The receiving circuitry amplifies the transducer probe signal and mixes it with a
signal from a fixed-frequency local oscillator to produce a beat note of about
1000 Hz when the microphone is responding to a signal of 40 kilohertz. The
amplified beat frequency is used to drive the internal speaker and also rectified to
operate the output meter. Plugging the headphones into the circuit diverts the
signal from the speaker to the headphones.

D2
Section D
DESCRIPTION AND SPECIFICATIONS (Cont’d.)
The circuit is powered from a 9-volt transistor type battery. The power
requirements are small enough so that the battery life is on the order of 75 hours
if used intermittently.
The circuit has sufficient gain available so that the sensitivity is limited only by the
noise of the input stage.
SPECIFICATIONS:
Operating frequency .......................range35 to 45 kHz
Directivity .........................................Distinguishes point sources
6 inches apart at 5 feet and
1 foot apart at 10 feet.
Output..............................................Headphones, speaker and meter.
Sensitivity.........................................Can detect corona sources in
air with as little as 5 micro-coulombs
at 5 feet.
Power Supply...................................9-volt transistor battery,
NEDA #1604, Burgess #2V6,
Eveready #216 or equivalent.
Components included:
Padded carrying case, receiver with meter and speaker, muff-type headphones
with 12 ft. retractile cord, microphone probe with 5½ ft. retractile cord, directional
horn with peep-sight and pistol-grip holder, rubber sound concentrator.
PHYSICAL
Dimensions......................................17 x 12 x 5 inches,
(432 x 305 x 127 mm)
Weight..............................................5½ lbs. (2.5Kg.)

D3
Section D
DESCRIPTION AND SPECIFICATIONS (Cont’d.)
ENVI RONMENTAL
Temperature range ..........................32ºF to 110ºF (0ºto 43ºC)
The instrument must be protected from direct exposure to water. It can withstand
the shock and vibration normally encountered in field use.
Catalog No. 569001-8 Contact Probe: Responds at 40kHz to minute
displacements in solid bodies.
Overall Length .................................10 inches (25.4 cm).
Diameter ..........................................1 3/4 inches (4.4 cm).
Probe Stem Length..........................6 inches (15.2 cm).
Probe Diameter ...............................1/8 inch (.32 cm).
Catalog No. 569001-7 Ultrasonic Tone Generator (Self-Contained)
Overall Size .....................................3½ x 2½ x 1 3/4 inches
(8.9 x 5.7x 4.4 cm).
Controls ...........................................On-Off Toggle Switch.
Power Supply...................................9-Volt transistor battery;
NEDA 1604. Burgess 2V6, Eveready
216.or equivalent.
Operating Frequency .......................Centered on 40kHz.

D4

E1
Section E
OPERATION
PRELIIMINARY
Select any accessories to be used with the basic system (microphone probe and
receiver). Fit the microphone with either the sound concentrator or the directional
horn by sliding it into the mating opening. In the case of the horn, the microphone
must be fully inserted into the socket and the two thumb screws tightened with
the fingers to prevent the microphone from dropping out if the horn is pointed
overhead. Now clip the receiver to a convenient article of clothing or hold it in
your hand. Connect the microphone probe cord to the fitting marked “PROBE’
making sure to tighten the lock ring.
If the headphones are to be used they are simply plugged into the jack marked
“PHONE”. Turn on the set by pushing the control thumb wheel to the left.
Increase the volume setting until the background noise is heard. Hold your hand
about an inch or two from the horn mouth (probe mouth) and lightly rub your
fingers together. This will produce a distinct output to insure that everything is
operating. Now turn the receiver off.
LOCATING CORONA SOURCES
Make a careful survey of the apparatus to be tested and take all precautions to
avoid electrical shock. Identify the high voltage terminals and suspected regions
to be examined. Choose a safe location that gives a clear direct air path to the
suspected area.
WARNING!
DO NOT APPROACH ENERGIZED APPARATUS WITH THE
HORN IN HAND: IT IS AN EXCELLENT ELECTRICAL
CONDUCTOR!
Turn on the receiver and scan the suspected area with the microphone probe by
simply pointing it at the suspected regions.
Corona, surface discharge or arcing will be readily identified over the background
noise. If the circuit is ac the corona will be identified as a very rough sounding
tone with the power frequency identifiable. The sound is similar to that produced
by passing a coarse file over the edge of a 3 x 5 paper card.

E2
Section E
OPERATION (Cont’d.)
If the apparatus is operating with dc, you will hear a series of popping sounds
when there is an intermittent discharge. For extensive discharges the sound
approaches a tone.
CONTACT PROBE
To use the Contact Probe, connect it to the receiver in place of the microphone.
Test the system just as for the microphone except lightly rub your finger on the
probe stem.
WARNING!
THE CONTACT PROBE IS NOT INTENDED TO PROVIDE
HIGH VOLTAGE INSULATION. IT SHOULD ONLY BE USED
WHERE NO DANGER OF ELECTRIC SHOCK EXISTS.
TONE GENERATOR
To use the Tone Generator, move the toggle switch to the “On” position. To
insure that the Tone Generator is operating, place it at least 5 feet away and
listen for a tone, using the receiver with the microphone. Be sure to keep the gain
setting low to avoid discomfort.