What is the formula for the length of each damper bar for small machines?

To determine the length of each damper bar for small machines, we usually refer to the specific design criteria of the machine in question, as the length can vary based on multiple factors including the electromagnetic design, the intended damping performance, and the operational speed range. However, without more specific information about the type of machine (e.g., synchronous machine, induction motor) or the intended application (e.g., generator, motor), it’s challenging to provide a one-size-fits-all formula.

Damper bars, which are employed primarily in synchronous machines to provide damping during transient states, are designed based on the electromagnetic characteristics of the machine. The length is often determined through electromagnetic finite element analysis during the design phase to optimize performance criteria such as starting characteristics, damping of oscillations, or transient response.

In general, the design of damper bars considers the effective length that contributes to the electromagnetic coupling with the machine’s magnetic field. This involves both the physical dimensions of the damper bars and their placement within the rotor structure. Nonetheless, a simplified approach for estimating the length might start from considering the physical dimensions of the machine’s rotor and the spatial constraints for installing the damper bars, following the principle that longer damper bars within the allowable space can potentially provide better damping due to increased interaction with the magnetic field.

For small machines, considerations might include ensuring the damper bars are of adequate length to span a significant portion of the rotor’s diameter or length, adjusted for any limitations due to the machine’s