Slip ring position is mainly installed on the drive shaft such as output axis of the unit, the input shaft and the output shaft of the gearbox, which uses with strain gauge. There are some performance of slip ring to be tested as follows: the shape and dimension, the single channel contact resistance and contact resistance when rotating, insulation strength between circuits, compression strength and friction at rotation. The value of the contact resistance fluctuation directly affects the signal, the quality of current transmission and stability of conductive slip ring operation. The detecting method is to mount the conductive slip ring on the detecting instrument. And the microvolter can test fluctuation value of single channel dynamic resistance when running. The fluctuation value of various contact resistance should be less than 10 ohm.
In general, there are some main reasons to cause large fluctuation value of contact resistance, such as bad contact between brush wire and metal ring. This case is mostly caused by low pressure or sundries in the contact or metal ring deformation. So it requires to carry out “5S” strictly. On the other, have control over the production process. When mounting brush wires, adjust the pressure and make it suitable. According to experience, about 10g is the best. That not only meets contact resistance, but won’t affect long because of friction. What’s more, we’d control time treatment of spindle installed with metal ring in order to not make ring road deformation.