TM 55-4920-402-13&P
Figure 2-11. Gram Scale
a. When using the Balancer for troubleshooting, the
object is to measure the vibration rate of the disturbance
and then match it against known rotation rates or harmo-
nics or multiples of known rotation rates in the helicopter.
b. The Balancer meter will read only if its filter is tuned
to coincide with the frequency (vibration rate) of a distur-
bance being measured along the axis of the Accelerometer.
Thus, if the IPS meter reads some vibration level, the
Accelerometer must be generating a signal at the frequency
at which the falter RPM TUNE dial is act.
c. When using the Balancer for troubleshooting, the
Strobex need not be plugged in, making it easier to probe
with the Accelerometer. Searching or scanning the frequen-
cies with the RPM TUNE dial must be done slowly at the
low RPM ranges (Xl on the RPM RANGE switch) and may
be done more rapidly at the higher ranges (X10 and X100).
Search with the VERIFY TUNE button released (broad, or
stagger-tuned filter) and when the meter reads, push the
VERIFY TUNE button (to the sharp filter position) and
sharp tune for the maximum meter reading. In this manner,
it is possible to read the vibration rate with an accuracy of
about 2%.
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