What condition would cause noise problems with the electromagnet of an electromagnetic starter?

The diagnosis of noise problems with the electromagnet of an electromagnetic starter is closely linked to the presence of foreign matter between the contact surfaces. When debris or contamination accumulates on these surfaces, it can hinder proper contact, leading to chattering or buzzing sounds during operation. This noise occurs because the contacts fail to engage fully due to the interference, causing the electromagnetic force to fluctuate as the starter attempts to operate.

Assessing the other options, excessive heat in the coil can suggest issues such as overloads or inadequate cooling but primarily affects the performance or safety rather than generating audible noise. An improper voltage supply could lead to the starter not engaging properly, which can create secondary issues, but it does not directly result in noise from the electromagnet itself. Long wire connections might introduce voltage drop problems, affecting efficiency or performance, yet it is not typically associated with creating noise directly from the electromagnet action.