Even if you stop the rotor at the heavy spot, the imbalance is still present once it starts spinning. The heavy spot creates an uneven force that affects the entire rotation. That's why balancing involves adding or removing weight at specific points on the rotor to even out the mass distribution. I guess that you typically need specialized equipment. The process usually involves using a balancing machine that can measure the imbalance and suggest where to add or remove weight. There are two main types of balancing: static and dynamic. Static balancing deals with correcting the mass distribution along a single plane, while dynamic balancing addresses imbalances across multiple planes, which is usually more complex and requires precise measurements.
