Chadwick-Helmuth 8500C - Parameter Setup; Balance Frequency; Figure 5-6. Balance Setup Screen

Parameter Setup
Mode l8500C/8500C+ Operators Manual
5-7
5.3 Parameter Setup
The 8500C/C+ supports the modification of several important parameters used to control data
acquisition and display during the balance measurement process. In general, these parameters are
automatically set when a balance chart is selected. They may, however, be overridden by pressing
SETUP
, which in turn displays the Balance Setup screen (Fi gure5-6). See Se ction4.2.3.4 “SETUP
Key” on pag e4-7 for more information on Setup screens.
Figure 5-6. Balance Setup Screen
Use the Arro wkeys to select the field whose contents are to be modified, and th
<CHANGE>
soft key
or the numeric keypad to effect the desired changes. Th
ENTER
soft key saves the changes and
resumes operation in Balance mode. Th
RESTORE
soft key restores to all fields the values that were
set by the most recent
ENTER
.
Once the Balance Setup screen parameters have been modified, you may alternately press
BALANCE
to save the changes and return to Balance mode, or
START
to save the changes and begin a balanc
measurement. In effect, both of these keys execute an implicit
ENTER
before performing their
respective functions.
The following sections describe in greater detail the various Balance Setup screen fields.
5.3.1 Balance Frequency
The
balance frequency
is the frequency at which a rotor balance is to be performed. On a spectral plot
of a vibration signal, it usually appears as a well defined peak whose vibration amplitude and
frequency characteristics were generated by an out-of-balance rotating element. During balanc
measurement acquisition, the 8500C/C+ attempts to lock onto a vibration signal at the balance
frequency and analyze it.
Set the balance frequency by entering the desired value from the numeric keypad. Balance frequency
can also be set in Spectrum mode with the
BAL FREQ
soft key. Note that when a balance chart is
selected, the current balance frequency value is automatically overridden with a default value from the
chart. This value must be within range of the rotor system's actual vibration signal ±6 .25percent of the
designated value. Otherwise, the 8500C/C+ is not able to locate the vibrational peak during balance
measurement. If a balance acquisition fails, take a spectral plot before a new balance measurement is
begun in order to set the balance frequency to a known actual value. S ee Section7.4.4 Setting th
Balance Frequency” on pa ge7-9 for details on acquiring spectral frequency plots and setting the
balance frequency with th
BA LFREQ
soft key.