Page 27 - June

METALWORKING EQUIPMENT AND TOOLS

labor-intensive and easier to implement. The fan assembly is placed on the workbench, on the
edge of the base plate and on the motor ventilation hood. With a light jolt, the impeller is given
a right-handed (if looking at the "blades") rotation and after it stops, a mark is applied with a
marker (chalk) on the upper part of the impeller disk and opposite it, a risk is applied to the fan
base plate. Attach a typical balancing weight (used) for grinding wheels for sharpening wheels
using plasticine on the inside of the disc at the place marked with a marker (chalk). That is, in
the "light" place of the impeller disk, the first weight is fixed. To the right and to the left of it
(in the sectors of the other "shoulder blades"),
two more weights are fixed. Set the impeller to
rotate again with a light jolt and by rearranging
the side weights (closer-further from the central
weight), the wheel stops in any (arbitrary) position
without pendulum (swinging) movements. After
making sure that there is no imbalance during
the rotation of the fan impeller and marking the
location of the weights on the disk with a marker,
the plasticine is replaced "Cold" welding. "Cold"
welding is necessary for more reliable fastening
of the balancing weights and subsequent drilling
in them, as well as in the wheel rim holes. A
central hole is drilled for a thread diameter M 8
and two side holes for rivets (D = 3 - 4 mm). An
M 8 screw with a countersunk head is screwed
into the central hole, rivets are inserted into the
side holes. The countersunk screw heads are
additionally welded to the balancing weights. This
is done to prevent self-loosening of the central
screws under the influence of centrifugal force
during the rotation of the impeller. After the final fixing of the balancing weights, the impeller is
again checked for imbalance. If it is present, by fusing welding metal onto the balancing weights
or by drilling a part of the metal from the balancing weights, the imbalance is finally eliminated.
The second method of static balancing is easier to implement from the point of view of its
technical support. Still, for the first method, turning work is required to make pins with a left-
hand thread, and most importantly, taps of the required diameter for cutting a left-hand thread
in the holes of the disc. Nowadays, not every OGM of our machine-building enterprises has such
a tool. However, the second method somewhat violates the aerodynamic qualities of the impeller,
creates some obstacles for the formation of an air flow. Therefore, the last method of static
balancing should be applied to industrial vacuum cleaners from the late USSR, in order to thus
be forced to extend their period. service. All industrial vacuum cleaners made in Soviet times
have one typical problem - the bending of the rotor shaft of the electric motor is higher than
the permissible technical standards. Fixing the balancing weights on the inner (working) surface

Stanochniy park 27