When the coil in a relay is energized or de-energized, it generates a magnetic field that moves the armature. In general, AC operation relays are equipped with a shading coil to prevent beat. However, if a small amount of foreign object (e. dust) gets caught in the pickup surface of the iron core and the iron piece, the balance of the pickup surface will be lost, causing beat. However, buzzing or humming noises can indicate issues such as low voltage, a stuck switch. Distribution boxes are the unsung heroes of our electrical systems, quietly managing power until something goes wrong.