Welding Resistance Test for armatures with windings connected in parallel through connection wires

The system AAT320/W carries out several ohmic resistance measurements particularly:

  • Ohmic resistance of each section (bar to bar). 
  • Ohmic resistance measured on the commutator diagonal. 
  • Incremental ohmic resistance of the various sections. 
  • Ohmic differential resistance between 2 opposite windings placed at 180°. 
  • Welding resistance between coil and each bar. 

 AAT320/W measures the ohmic resistances of all coils. For instance, if you have an armature with N bars, N measurements are carried out between consecutive bars (bar1/bar2; bar2/bar3; …. bar(N-1)/N) or also not consecutive bars with a programmable step between bars.

The measurement is carried out according to the Kelvin method, with 4 wires.

The new model of hooking head guarantees that the “four wires” are kept until the physical contact with the commutator bars without the insertion of in-between junctions.

AAT320/W includes the function of “thermal compensation of the Ohmic resistance measurement” with the possibility to set the wire material (copper or aluminum) and the reference temperature (20°C or 25°C or any other value). The temperature sensor can read the ambient temperature as well the armature real temperature.

One of the most important characteristics of AAT320/W System is the possibility of checking the weld resistance between winding and related bar. This test is carried out by means of a patented method. A new improvement allows the possibility to make the measure with hot hooks due to the welding operation. This method reduces the need to have cooling system or the necessity to increase the tolerance of measure.