Two. Four-point method Troubleshooting
Detected by the above, maintenance is completed, if the fault still
exists, the balance can be described by the following four o'clock
machine balancing machine test method to test. Under normal
circumstances, so the user can use the physical rotor. If necessary,
users can use the following process and record all the data then
available to balance the machine manufacturer, the manufacturer can
determine the basis of this record more than 90% of the fault.
1, the first rotor balance to be able to achieve the highest
accuracy, and then prepare a residual rotor unbalance is greater
than 30 to 50 times the removable weights (according to the
following procedure: Using weights 100 g, the residual amount of the
rotor should be less than 2 to 3 grams). Rotor and load balancing
machine coupling and the form of the same, directly following the
testing process.
2, check the balance of the various machine settings are normal.
3, either side of the rotor circumference at the specified weight
add 45 degrees to a known weight of removable weights (the weights
by assuming 100 g).
Start balancing machines, balancing machines indicated value
corresponding to the surface should be 40-50 degrees, 90-110 g (90%
according to weight ratio).
4, shutdown will be removed with weights installed on the same side
of the circumference of the rotor angle of 135 degrees.
Start balancing machines, balancing machines indicated value
corresponding to the surface should be 130-140 degrees, 90-110 g
(90% according to weight ratio).
5, stop and then remove the weights installed on the same side of
the circumference of the rotor angle at 225 degrees.
Start balancing machines, balancing machines indicated value
corresponding to the surface should be 220-230 degrees, 90-110 g
(90% according to weight ratio).
6, stop and then remove the weights installed on the same side of
the circumference of the rotor angle at 315 degrees.
Start balancing machines, balancing machines indicated value
corresponding to the surface should be 310-320 degrees, 90-110 g
(90% according to weight ratio).
7, the same process, the other side of the rotor weight specified
point on the circumference at four weights in order to install this
check.
8, such as balancing machines can be up to the requirements stated
above is considered to balance the machine without any problems.
9, such as balancing machines can approximate to the above
requirements is considered minor balancing machine calibration
inaccuracies. This problem usually caused by a decline in operating
efficiency, without causing large errors.
If there was a slight balancing machine calibration inaccuracies,
the user can balance the machine matching the content rule out the
instructions, may also notify the manufacturer for processing.
10, such as balancing machine does not meet the above requirements,
and the error is very large, the user shall notify the manufacturer
for processing.
11, special circumstances, the user to balance the machine accuracy
or quality of doubt, you can balance the machine on the four-point
method for fault diagnosis.
Sometimes users will find that the rotor has been balanced on the
balancing machine precision, the above method of testing that
balancing machines are all normal, but the actual installation of
the rotor running, or have some degree of vibration, then you need
to carefully analyze other aspects of the process why.
Three. Careful analysis of the vibration of the reasons, the right
to determine the accuracy of the real balance
Mechanical vibration caused by many reasons, including its balance
of rotating parts caused by the vibration of the most direct. But
this does not mean that the rotor balancing machine balance in a
good future, they can solve all vibration problems.
Rotor imbalance is due to the rotor's center of gravity, the
rotation of the rotor geometry deviation from the centerline. The
rotor rotates the resulting centrifugal force together with the
rotor rotation, the rotor and the rotor in order to stimulate the
installed base (such as: bearing, frame, chassis, body, etc.) to
vibrate.
The following will discuss some other related process issues.
1, the process itself, problems balancing machine
Precision balance, should be considered universal coupling,
connectors and other related key influence. Small rotor balancing
process requires additional ancillary quality of the cursor, but
also need to consider their impact on the accuracy of the final
balance. When these connections related to the amount of close to or
even caused by the imbalance of the rotor balance is greater than
the precision of user requirements, the balance machine shows the
unbalance is not reliable. Drive with a universal coupling for the
balancing machine, universal coupling should also be regularly
checked the balance of accuracy.
When using the balance shaft technology, process shaft runout
accuracy can not be greater than the rotor balance index e
(eccentricity), or 1800 high-precision balance must be flipped. Or
process axis scrapped.
In addition, the process structure and the rotor shaft axis of the
actual installation of the structure, should be made into the same
or similar to ensure that its mass distribution consistent with the
actual installation of the state.
2, the rotor of the process issues
Balancing machine using the user should try to install the real
state of rotor balance, and ensure its rigidity.
Axis to balance the use of technology, there is the actual
installation process and the rotor shaft axis error, such as the
rotor shaft in the process and the actual axis of different
installation methods, keyway structure, process and the actual shaft
axis and the beating of their own, these factors will lead to uneven
measurable change.
Axis to balance the use of technology, we must ensure that the rotor
mounting hole dimensional accuracy and geometrical tolerances, such
as: the gap is large, oval or tapered hole error, low roughness is
absolutely not allowed.
Another must ensure that the rigidity of the rotor. If an internal
sliding splined rotor, active block, swing knife block and other
similar structures, such as the rotor is never reach the ideal
balance of accuracy.
3, the actual installation process issues rotor
Rotor balancing machine has reached the required balance of
precision, the actual installation of the rotor operation, if the
actual installation process do not seriously consider certain
factors, or the changes will result in a balance accuracy, as well
as causing a certain degree of vibration.
The first is the actual installation of shaft runout, this factor is
very important. Because the rotor imbalance is due to the rotor
center of gravity, deviation from the geometric center of rotor
rotation. The rotor rotates the resulting centrifugal force together
with the rotor rotation, the rotor and the rotor in order to
stimulate the installed base of vibration. The balance of good
eccentric rotor is installed in the actual installation of the shaft
has, of course, will lead to the vibration of the rotor and the
machine.
In addition, coaxial with the rotor will cause the rotor and other
parts of machine vibration, such as belt pulleys, couplings, rotor,
etc., their precision will balance together with the rotor in the
machine vibration.
4, other issues
Our technical staff during the service found that there are some
balancing machine users in their production process, pay attention
to grasp the early stage of manufacturing quality of its products,
and operational performance of its rotor completely dependent on the
balancing process, it is very not serious. For example:
Product design process does not consider the process of balancing;
Products based components (such as brackets, etc.) cut corners or
even seriously flawed;
Fan rotor or rotor shape welded face beating too large;
Uneven distribution of the quality of the rotor casting error is too
large;
The rotor mounting hole precision and roughness is too low;
The internal structure of the rotor there is a serious non-rigid
factors (such as: weld, loose rivets, etc.);
Roughness and accuracy of technology-axis low;
Actual installation of the rotor shaft is too low precision and
roughness;
All of these factors will lead to reduced accuracy even balance
balance failure.
