TABLE OF CONTENTS A rotor with a single unbalance. This illustration also appears on page 96 where we discussed a similar concept.
How easy it would be if rotors came like this and you could just knock off the unbalance.
Normally you cannot see the actual unbalance; it is the total of a number of small manufacturing errors.
One of the problems with balancing is that you cannot directly see or measure the unbalance, only the effect of the unbalance. You cannot see electricity either but the effects can be just as dramatic if you ignore either one. Did you ever receive an electric shock? Did you see it coming?
To represent the sum total of all the unbalance of the rotor we show a single mass at a specified radius. U = m r This defines the magnitude of the unbalance.
| Note | The unbalance is located at a specific angular location which must also be known or there is no way to make correction. |
If we just need to know if unbalance level is 'OK' or 'NOT OK', we can ignore the angle in this case.
