Abstract: An objective and non-destructive test of the fused joints in an armature, that can be used on every armature being manufactured on an armature manufacturing line, as well as apparatus for performing that test, are provided. The armature is immersed in an acoustic coupling medium. Acoustic pulses, preferably ultrasonic pulses, are beamed onto the commutator tang/wire interface region of a commutator tang/bar fused joint or the fused joint itself and an acoustic signature is measured. The quality of the joint can be determined by comparing the acoustic signature to a predetermined acoustic signature of known quality. A testing station on an armature production line includes a mechanism for removing the armature from the production line, immersing it in the coupling medium, and rotating it as each joint in the commutator of that armature is checked.

Abstract: An objective and non-destructive test of the fused tang/commutator bar joints in an armature, that can be used on every armature being manufactured on an armature manufacturing line, as well as apparatus for performing that test, are provided. The armature is immersed in an acoustic coupling medium. Acoustic pulses, preferably ultrasonic pulses, are beamed onto the joint and the reflected pulses are measured. The quality of the joint can be determined by comparing the reflected amplitude to the known reflected amplitudes for joints of known quality. A testing station on an armature production line includes a mechanism for removing the armature from the production line, immersing it in the coupling medium, and rotating it as each joint in the commutator of that armature is checked.