Field balancing is vector arithmetic, and a reader cannot balance a rotor from a description of it. Both methods are worked here in full: the original reading, the trial run, the difference vector that isolates the trial weight’s effect, and the correction that follows, on one plane and on two.
It opens with the check that saves the most money, which is confirming the machine is actually unbalanced before a weight goes anywhere near it.
Study material written by Sensemore. It is not accredited training, it is not from any certification body’s question bank, and it confers no certification.