This video contains Paid links that gives me a 6% commission if you click and buy any product on that website . Check out my web site Check out my store front
Support this channel on Patreon Check out my store front bottle valve In this video we look into static balancing, balancing rotoating masses is very difficult so i decided to try a new aproauch to the problem of rotor balancing .
be found in a rotor whose diameter is
less than 7 to 10 times its width. In the
case of a cylinder, shown in Fig. 2, it is
possible to have two equal masses
placed symmetrically about the centre
of gravity, but positioned at 180° from
each other. The rotor is in static balance,
i.e. there is no eccentricity of the
centre of gravity, but when the rotor
turns, the two masses cause a shift in
the inertia axis, so that it is no longer
aligned with the rotation axis, leading
to strong vibrations in the bearings.
The unbalance can only be corrected
by taking vibration measurements
with the rotor turning and adding correction
masses in two planes.
The difference between static balance
and couple balance is illustrated
in Fig. 3. It can be seen that when the Fig. 2. Couple unbalance
rotor is stationary, the end masses balance
each other. However, when it rotates,
a strong unbalance is experienced.
Dynamic Unbalance, illustrated in
Fig. 4, is a combination of static and
couple unbalance and is the most common
type of unbalance found in rotors.
To correct dynamic unbalance, it
is necessary to make vibration measurements
while the machine is running
and to add balancing masses in
two planes.
Rotors are classified as being either
rigid or flexible. This Application
Note is concerned with rigid rotors
only. A rigid rotor is one whose service
speed is less than 50% of its first
critical speed. Above this speed, the
rotor is said to be flexible. A rigid
rotor can be balanced by making corrections
in any two arbitrarily selected
i rnr u i ■ A £ Fig. 3. Static balance, couple unbalance
planes. I he balancing procedure tor *
flexible rotors is more complicated,
because of the elastic deflections of
the rotor.
Fig. 4. Dynamic unbalance
O
Principle of Balancing
A rotor is balanced by placing a correction
mass of a certain size in a position
where it counteracts the unbalance
in the rotor. The size and position.
of the correction mass must be
determined.
The principle of performing field
balancing is to make (usually temporary)
alterations to the mass distribution
of the rotor, by adding trial
masses, and to measure the resulting
phase and magnitude of bearing vibration.
The effects of these trial corrections
enable the amount and position
of the required correction mass to be
determined. The values are usually
calculated with the aid of a pocket
calculator.
Fig. 5. The basic measurement chain
Any fixed point on the bearing experiences
the centrifugal force due to
the unbalance, once per revolution of
the rotor. Therefore in a frequency
spectrum of the vibration signal, unbalance
is seen as an increase in the
vibration at the frequency of rotation.
The vibration due to the unbalance
is measured by means of an accelerometer
mounted on the bearing housing,
see Fig. 5. The vibration signal is
passed through a filter tuned to the
rotational frequency of the rotor, so
that only the component of the vibration
at the rotational frequency is
measured. The filtered signal is
passed to a vibration meter, which displays
the magnitude. The indicated
vibration level is directly proportional
to the force produced by the unbalanced
mass.
The phase meter measures and displays
the phase between the signal
from the tachometer probe (the reference
signal) and the filtered vibration
signal. The angle displayed by the meter
enables us to locate the angular
position on the rotor of the unbalance,
relative to the datum position. DISCLAIMER: In this video description contains affiliate links, which means
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very nice tool
As it slows down in the end it does look like the hole isn't in the middle.
*sophisticated
What is the name of the app you are using to measure the vibration on your phone?
Safisticated? what the hell is that?
It's Sophisticated you pinhead
Pretty good . Seems very acceptable method with very simple tools.
This is really not the proper way to balance that metallic fan… just imagine due to harmful cavitation due to vibration for long period of time, something will snap in those missing hole area and now you got a deadly/lethal shrapnel flying out… it would be better to add some kind of weight like "aluminum tape" to the area which has "less" mass. Keep adding heavy tape in layers of the region where the fan weight area is less. This explains why many people disliked your video.
How was that data getting to the phone?
what rpm was that doing
great video man really, but how would it work if you added weight to opposite end, you could drill and weight nuts and bolts to more accurately estimate imbalance, although it could cause vibration in a different plane. just a thout no criticism at all, of course i just seen the video is 4yrs old
also! the vibration frequency is based on RPM of the electric motor.
some tips: avoid using nice phones for this. strong vibes can loosen weak solder joints and ruin your phone. My gf broke hers by just using it as a gps in a phone holder on a single cyl motorcycle. For the needle point you can put the shaft you want to use in a drill and sharpen the end on a belt sander for a fine point.
Good Vibration App is free?
If you have Samsung phone. You can access the sensors data by dialing *#0*# and then tapping on the sensor box. It might work on other Android phones, I haven't tested it.
Awesome sauce..
The phone contains a 3 axis accelerometer and the app is designed to show the X, Y, Z axis. Great. But, the balance pin you made is for static balance reference only. Grind the shafts tip to a fine point to see better bench results. Now, placing the phone with app, on the bench next to the vise will provide skewed readings in my mind. Holding the phone on top of the motor should improve accuracy I would think. This gets it closer to the imbalance as possible. Very interesting! In the auto shop, during the 70’s into the 80’s, with the vehicle raised and a dedicated motor device would drive the tire, wheel, axle or hub all. It’s been so long ago but I remember having to place a hand on the inside of the fender with your index finger extended. It would vibrate and chalk was used to mark the location to add weight, then retest.
Too many moons ago to be exact as equipment changed all of the time. But this was a dynamic balance not static. What we called the bubble balancer was closer to your bench pin & cup. I believe that modern balances used light thru a slotted wheel until 3-axis accelerometers become accurate, check and smaller than your smallest finger nail. Nice job anyways!
ASE Master Tech since 1978 – Retired
Very nice, I did the same thing to balance a pulley on my engine.
Did you measure from the center of the hole to the outer circumference to check for concentricity so as instead of drilling holes and sacrificing durability maybe have ground some of the metal off of the ends of the blades where it would have had more effect to true balance? Was the hole in the actual center?
thanks m8 Im trying to make some 30k rpm tops and this really helped me achieve balance
apple why why apple lol i just got a https://www.amazon.com/gp/product/B07JY9SVNM/ref=ppx_yo_dt_b_asin_title_o09__o00_s00?ie=UTF8&psc=1 69 bucks it a good buy a that price i wish i got the other one that bigger
A mind is a beautiful thing to waste..
The frequency increase is because the motor is turning faster.
"Safisticated"… Love it