Goldak 600 User manual

CONTENTS PAGE NO.
A. General Description . . . . . . . . . . . . . . . . . . . . . . . .1
II. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
A. Functions of the Controls . . . . . . . . . . . . . . . . . .3
1) Gain Control . . . . . . . . . . . . . . . . . . . . . . . . . .3
2) Selector Switch . . . . . . . . . . . . . . . . . . . . . . . .3
B. General Operating Principals . . . . . . . . . . . . . . .4
C. Preliminary Procedures . . . . . . . . . . . . . . . . . . . .7
D. Maximizing (or Peaking) Technique . . . . . . . . . . .8
E. Minimizing (or Nulling) Technique . . . . . . . . . . . .11
F. Depth Measurement . . . . . . . . . . . . . . . . . . . . . .14
G. Locating, Transformers, Splices, & Faults . . . . .17
1) Underground Transformers . . . . . . . . . . . . . .17
2) “T” Splices and “Y” Splices . . . . . . . . . . . . . .18
3) Grounded Faults . . . . . . . . . . . . . . . . . . . . . . .18
H. Operating Suggestions & Cautions . . . . . . . . . .19
III. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
IV. Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

1) General Description:
The Model 600 Power Cable Locator is an electronic instrument for
locating, tracing, and measuring the depth of energized power
cables. It can also be used to locate underground transformers,
T-splices, Y-splices, and grounded faults.
Structurally, the “Kab-L-Tec” consists of a high impact plastic control
box fastened to a pistol-grip handle and connected through an
extension arm to a swivel mounted detection rod (Fig. 1). By turning
the swivel, the detection rod can be set into detented positions
either parallel to the extension arm, perpendicular to it, or inclined
at 45 degrees to it (Fig. 3, 6, and 9). The controlbox contains and
shields the electronic circuitry; on its face are mounted a gain
control, a selector switch, a phone jack, and a meter (Fig. 2).
The pistol-grip handle not only serves as a means of grasping the
instrument but also houses its 9 volt battery in an easily removable
clip (Fig. 13). A set of high impedance headphones completes the
instrument.
Model 600 Power Cable Locator
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Electrically, the detection rod is inductively influenced by the
electromagnetic field associated with the current, which is flowing
through a cable. The signal thus received by the detection rod is
amplified by the circuitry in the control box. With the gain control
and the selector switch, the operator can vary the amount of
amplification over a wide range, can adjust the degree of meter
sensitivity, and can also test the state of the battery at any time.
The amplified signal is heard through the headphones and is
indicated visually by the meter.
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II Operation
A) Functions of the Controls
1) Gain Control – The gain control (Fig. 2) is a multi-turn
potentiometer which provides a smooth and continuously
variable adjustment of the amplifier’s gain and rotating it
counterclockwise gradually decreases the gain.
2) Selector Switch – The selector switch at the right of the
panel (Fig. 2) has six positions.
a) Its first position is “off”. When this switch is set to this
position, the battery is disconnected and the entire
circuit is turned off.
b) Its last position is for testing the state of the battery
and is so labeled. When the switch is set to this posi-
tion, the meter-needle will indicate the condition of the
battery: if the meter-needle deflects into the green area
at the right of the scale, the battery is good; if the
meter-needle falls to the left of the green area, the
battery should be replaced.
c) The second, third, fourth, and fifth positions of the
selector switch adjust the sensitivity of the meter
response to signal reception. The second position
provides the lowest level of meter sensitivity, the fifth
position provides the highest level of meter sensitivity,
and the third and fourth positions provide intermediate
levels. Because experience proves that the lower levels
of meter sensitivity are more useful for operating in
the maximizing technique (explained below) while the
higher levels of meter sensitivity are more useful for
Model 600 Power Cable Locator
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operation in the minimizing technique, the second and
third positions of this switch have been labeled “peak”
and the fourth and fifth positions have been labeled
“null”.
B) General Operating Principles
1) In searching for buried cables, the Model 600 “Kab-L-Tec”
is always carried and operated vertically. The operator
grasps the instrument by the pistol grip handle and holds
it so that the detection rod is close to the earth.
2) The signal “sensed” by the detection rod is amplified by
the circuitry in the control box. By adjusting the gain
control, the operator can regulate the amount of amplifi-
cation that is imparted to the signal. He should always
adjust the gain to produce a response level at the meter
and headphones that is strong enough to be observed
but not so strong as to saturate the circuit and thereby to
render imperceptible the variations that may occur in the
“sensed” signal.
3) What the detection rod “senses” is the electromagnetic
field propagated from the energized cable. The strength
of the signal “sensed” at the detection rod, therefore,
depends primarily on three factors; (a) the amount of
current flowing through the cable, (b) the distance
between the detection-rod and the cable, and (c) the
position in which the detection rod is oriented with
respect to the cable.
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a) The greater the current through the cable, the stronger
will be the signal “sensed” by the detection rod at any
point. Conversely, the less the current through the
cable, the weaker will be the signal “sensed” by the
detection rod at a given point. If we can assume,
however, that the amount of current in a given cable
will remain fairly constant throughout the duration of
the operator’s search for the cable, this factor will not
enter into the operating technique.
b) The distance between the detection rod and the ener-
gized cable is a factor that is varied during operation.
The farther the detection rod is from the cable, the
weaker will be the “sensed” signal; the closer the
detection rod is to the cable, the stronger will be the
“sensed” signal. In walking toward the cable, in cross-
ing it, and in walking away from it, the operator is vary-
ing the distance between the detection rod and the
cable (as well as the orientation of the detection rod
with respect to the cable -- see below), and the
“sensed” signal will vary in accordance with this.
c) Varying the orientation of the detection rod with respect
to the cable at any given distance from the cable will
alter the strength of the “sensed” signal at that point.
The operator varies this orientation not only by the
angle at which he sets the detection rod at its swivel
but also by the positions in which he is located as he
approaches, crosses, and recedes from the cable.
Whenever, at any point, the length of the detection
rod is aimed in a line-of-sight at the energized cable,
the signal “sensed” by the detection rod will be at an
extreme minimal level for that particular point.
Model 600 Power Cable Locator
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Whenever, on the other hand, the detection rod is so
oriented that its length is aimed in a direction perpendi-
cular to the run of the cable and that its ends are equidis-
tant from the cable, the signal “sensed” by the detection-
rod will be at an extreme maximum level for that particular
point.
4) The techniques, therefore, of locating or tracing a buried
energized cable depend on interpreting variations in
response-level for controlled variations in distance from
the cable, in orientation of the detection rod with respect
to the cable, and in amplifier gain. Two general techniques
are possible: the maximizing (or “peaking”) technique and
the minimizing (or “nulling”) technique. The maximizing
technique requires that the detection rod be so oriented
as to have maximum sensitivity when directly over the
energized cable. The minimizing technique requires that
the detection rod be so oriented as to have minimum
sensitivity when directly over the energized cable.
In both techniques an initial reference level of signal
response is set by adjustment of the gain control, and
then variations are observed as the operator carries the
instrument into positions that approach the cable, that lie
directly above the cable, and that recede from the cable.
In the maximizing technique, the variations in the opera-
tor’s position as he walks (which are equivalent to varia-
tions in the distance and orientation of the detection-rod
with respect to the cable) cause the signal response to
rise to the maximum value possible when the detection
rod is directly over the cable. In the minimizing technique,
the variations in the operator’s position as he walks (which
are equivalent to changes in orientation of the detection-
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rod with respect to the cable) cause the signal-response to
fall sharply when the instrument is directly over the cable.
C) Preliminary Procedures
Before attempting to operate the “Kab-L-Tec”, some
preliminary procedures are necessary.
a) Plug the headphones into the phone jack. This, howev-
er, is optional. The “Kab-LTec” may be operated with-
out headphones; the operator need only observe the
meter.
b) Turn the “Kab-L-Tec” on by rotating the selector switch
clockwise out of the “off” position. Allow an interval of
a few seconds for the complete charging of the circuit
stabilizing capacitors; at the end of this period the
meter needle will come to rest.
c) If desired, the battery may be checked at this point.
To do this, turn the selector switch to “battery test” and
observe the indication of the meter (--see explanation
above, Part II, Section A). When the battery test is
completed, return the selector switch either to one of
its “peak” or to one of its “null” positions.
d) Place the detection rod at the desired angle of orienta-
tion (perpendicular to the extension arm for the
“peaking” or maximizing technique, or parallel to the
extension arm for the “nulling” or minimizing technique,
as described below and shown in Fig. 3 and 6).
e) Grasp the instrument by the pistol grip handle, and
hold it vertically so that the detection rod is within four
inches of the surface of the earth. The instrument is
now ready for operation.
Model 600 Power Cable Locator
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D) Maximizing (or Peaking) Technique
The maximizing technique locates or traces an energized
cable by seeking the line of greatest signal response. For this
mode of operation, the detection rod is placed in the detent-
ed position that sets it at right angles to the extension arm
(Fig. 3); consequently, as he instrument is held in its normal
vertical position, the detection rod is horizontal and parallel
to the surface of the earth. The selector switch is set to one
of its “peak” positions.
To locate the cable, the
operator holds the “Kab-L-
Tec” vertically and aligns the
pistol grip handle parallel to
the expected direction of
the cable (Fig. 4). He then
adjusts the gain control for
a signal level that will make
the 60Hz. hum audible on
the headphones and will
deflect the meter needle to
approximately half scale
(a meter reading of “50”).
This will serve as an initial
reference level. The operator
then scans the earth by
walking laterally with the
instrument and keeping the
pistol-grip handle parallel
to the expected run of the
cable (Fig. 4). If the meter
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Model 600 Power Cable Locator
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If the meter needle falls as he walks, he is walking in the
wrong direction; if it rises, he is walking toward the energized
cable. When the meter needle reaches full scale deflection
(”100”), the gain of the amplifier must be reduced so as to
provide a new reference level of half scale deflection (”50”).
Again the operator walks literally toward the cable, and again
the meter needle will rise. Each time that the meter needle
reaches full scale deflection, the gain must be reduced again
to provide another reference level of half scale deflection.
This process is repeated until a point is reached where the
signal-response no longer rises but begins instead to fall.
This point of maximum or “peak” response will be located
directly above the energized cable; on either side of the
cable the response will fall to lesser levels (Fig. 4 and 5).
Consequently, by finding the point of maximum response,
the energized cable is “located”.
The “located” cable may now be “traced” along its entire run
by the nonmaximizing technique. The operator maintains the
“Kab-L-Tec” in the same orientation, that is, with the pistol-
grip handle parallel to the run of the cable. He sets the main
control for a reference level of half scale deflection (”50”)
directly over the cable. he then walks forward and moves the
instrument to his right and to his left as he walks. Each time
that the detection rod crosses the energized cable, the signal
response will peak to a maximum; each time that the detec-
tion rod moves to the left or the right of the cable, the signal
response will fall to lesser levels. By following the sequence
of these points of maximum response, the operator traces
out the line under which the cable lies.
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E) Minimizing (or Nulling) Technique
The minimizing technique locates or traces an energized
cable by seeking the line of least signal-response. For this
mode of operation, the detection-rod is placed in either of
the detented positions that sets it parallel to the extension
arm (Fig. 6). Consequently as the “Kab-L-Tec” is held in its
normal vertical position, the detection-rod likewise is vertical,
that is, its length is pointing straight up and down. The selec-
tor switch is set to one of its “null” positions. To locate an
energized cable, the operator holds the instrument vertically
and adjusts the gain control for a response level that will
make the 60-Hz. hum audible on the headphones and will
advance the meter-needle up to a reading of “100” (full
scale).
Model 600 Power Cable Locator
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This will serve as an initial reference level. The operator then
scans the earth with the instrument, moving it in a direction
which will cross over the expected run of the cable. The full
scale reference level signal will remain until the instrument
crosses over the energized cable. As it crosses to a minimal
level, the cable lies directly under the point where the signal
response “nulls out” (Fig. 7 and 8). (Note -- if the nulling of
the signal occurs over an area which is too broad for deter-
mining accurately where the cable lies, the amplifier’s gain
should be increased; increasing the gain will “sharpen” the
response and make the null-area narrow enough to allow
precise pinpointing of where the cable lies. Conversely,
if the null-area is so “sharp” that it is difficult to detect it at
all. The gain of the amplifier must be reduced.) Finding a
sharp null-point thus “locates” where the cable lies.
The “located” cable may now be “traced” along its entire run
by the same minimizing technique. By finding two null-
points, the operator can determine the direction in which the
cable runs. He then walks with the “Kab-L-Tec” in the direc-
tion of the cable’s run and moves the “Kab-L-Tec” to his left
and to his right as he walks. Each time that the detection rod
crosses over the energized cable, the signal response will
“null out” to a minimum, and each time that the detection
rod moves either to the right or to the left of the energized
cable, the signal response will rise sharply to a high level.
By following the sequence of these null points, the operator
traces out the line under which the cable lies.
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Model 600 Power Cable Locator
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F) Depth Measurement
The technique of measuring the depth of an energized cable
is a combination of “nulling” techniques in a precise triangu-
lar relationship.
First, the operator must “locate” the line of energized cable
by the “nulling” technique as described above (Part II,
Section E, pp. 11) and shown in fig. 7 and 8 (p. 13). The
operator marks the surface of the earth at the point of mini-
mum signal response: this mark will lie directly above the
cable.
Secondly, the operator changed the orientation of the detec-
tion rod to a 45-degree position; either the left 45-degree
detent or the right 45-degree detent may be used (fig. 9,
p. 15). The operator then holds the instrument so that the
pistol-grip handle is aligned parallel to the run of the cable
and adjust, if necessary, the gain control for a full-scale
reference-level reading (”100”) on the meter (--normally it will
not be necessary to readjust the gain control from the setting
used previously for “nulling” directly over the cable). The
operator then walks laterally to the side on which the high
end of the detection rod is situated. (Thus in fig. 10, p. 16,
the operator is walking toward the left of the page, whereas
in fig. 11, p. 17, the operator is walking toward the right of
the page). The operator continues to walk laterally with the
“Kab-L-Tec”, holding the detection rod as close to the
ground as possible, until the signal response “nulls out”
(fig. 10 and 11, pp. 16-17). At this point of minimum signal
reception, the length of the detection rod is aimed in a line of
sight at the cable. The operator marks the surface of the
earth at this point. (Note -- if the nulling of the signal occurs
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over an area, which is too broad for determining precisely
where the earth is to be marked, the amplifier’s gain should
be increased, increasing the gains will “sharpen” the
response and narrow down the null area. Conversely, if the
null area is so “sharp” that it is difficult to detect it at all,
the gain of the amplifier must be reduced).
Thirdly, the operator measures the surface distance between
the two marks which he has made on the surface of the
earth. The distance between these two marks will be equal
to the distance from the surface of the earth down to the
cable (fig. 12, p. 19).
Model 600 Power Cable Locator
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When taking depth measurements, it is best to check oneself
by taking two measurements, one on one side of the cable
and the other on the other side of the cable (as in fig. 10 and
11, pp. 16-17), and then to compare the two. Normally,
provided these measurements are taken carefully and accu-
rately, they will be equal. When they are not equal, this will
be due to distortion of the electromagnetic field caused
either by a splice, by a change in the cable’s direction, or
by an adjacent utility line; in such cases, the cable will lie
at a depth which corresponds to the longer of the two
surface-measurements.
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G) Locating Transformers, Splices, and Faults
1) Underground Transformers
To locate an underground transformer, the operator first
locates an energized cable connected to the trans-
former. He then traces the cable toward the trans-
former by the maximizing technique described previ-
ously. (Note -- the nulling technique cannot be used for
locating a transformer). Since the electromagnetic field
propagated from a transformer is many times greater
than that propagated from the cable, the signal
response will rise greatly as the operator walks into the
vicinity of the transformer and will continue to rise until
the detection rod is directly over the transformer. Each
time that the increased signal-response “pegs” the
Model 600 Power Cable Locator
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meter to full scale deflection, the operator must
decrease the gain to bring the meter-needle back on
the scale. The transformer will be located under the
point of maximum response.
2) T-Splices and Y-Splices
To locate an underground T-splice or Y-splice, each of
the three energized cables that join in the splice must
first be located at a distance from the splice. Each of
these lines in then traced by the maximizing technique
to determine the course in which it runs. The splice will
be located where the lines converge or intersect.
(Note: Because of the complex patterns of the electro-
magnetic field near a splice, the nulling technique
cannot be used reliably near a splice.) In tracing each
of the lines toward the point of convergence, adjust-
ments may have to be made on the gain control in
order to compensate for different levels of current in
the different lines connected to the splice.
3) Grounded Faults
To locate a fault in which there is current-flow to
ground, the energized cable is first located. It is then
traced by the maximizing technique as described
above. When the instrument passes over a fault, a
notable change will be observed in the response-
level of the meter; this is due to a change in the line-
current and/or to a change in the pattern of the
electromagnetic field.
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