Installation, Operation and Service Manual LKP Series
© 2020 DynAmp, LLC Page 19
041736 N
B.) The necessity of moving the Measuring Head because of voltage readings that are too
high or too low for certain channels.
C.) The desirability of moving the Measuring Head to obtain a better balance of channel
voltages.
Study the initial voltage readings. First, if none of the readings are below 3 V or above 30
V, the Measuring Head position may be left as is. If some of the voltages are in the 31-40
V range, a change should be considered. In some cases, a channel fuse might blow if the
channel voltage is above 35 volts. In those cases, the Measuring Head will have to be
moved, or, if the Measuring Head can’t be moved, then a higher rated fuse can be
installed. Using higher rated channel fuses shall be evaluated and approved by the factory
only on a case-by-case basis. If any readings are over 40 V, the Measuring Head must be
moved.
As the voltage readings are compared from channel-to-channel around the Measuring
Head, a pattern may be observed which indicates that a section of adjacent channels has
higher-than-average readings, whereas the section 180° across the bus has lower
readings. Looking for patterns of this type will help in deciding how the Measuring Head
should be moved to obtain a better balance of channel voltages.
As a simplified example of optimizing the Measuring Head position, assume these readings
are obtained for two pairs of directly opposite channels:
Chan 1 = 25 V and Chan 5 = 12 V
Chan 3 = 36 V and Chan 7 = 12 V
Note that it is not sufficient to consider just a few channels; all channel readings must be
considered for repositioning. However, for this simplified example the Measuring Head
would be raised (relative to the bus) to balance the channels 3 and 7 voltages, and moved
horizontally (bringing channel 5 nearer the bus) to balance the channels 1 and 5 voltages.
Note that (1) it would not be necessary to change the horizontal positioning since the
channel 1 voltage is not excessive and (2) an absolute balance between opposing chan-
nels is unnecessary. Lowering the higher readings (31 V or higher) is more important than
achieving perfect balance.
If the Measuring Head position must be changed it is important that it be kept in a
vertical plane if possible. The Measuring Head can be mounted in a tilted plane without
loss of accuracy. However, such mounting can impose stresses at the center joining
points especially if one half is supported solely from the other half.
If it is necessary to tilt the Measuring Head out of the vertical plane by more than 20° to
achieve lower channel voltages, first make sure each half is independently supported at
four points, and then carefully loosen the joining bolts. Independently move each half into
the new position, visually align. Firm up the support system and re-bolt. A gap of at least
¼in. (7 mm) must be maintained between any part of the Measuring Head and bus to
prevent possible buildup of a conductive dust path between them.
Using the initially recorded channel data, move the Measuring Head position as necessary
or desirable, observing the above precautions. Make spot readings of the channels in
question to confirm results. When the spot readings are satisfactory, record their values
and measure and record the values of all other channels on the diagram in Table 4.3 or
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