METHOD AND DEVICE FOR TESTING COMPOSITE BRUSHES Russian patent published in 1998 - IPC

FIELD: electrical engineering; testing electrical machine brushes prior to their use. SUBSTANCE: composite brush testing device has current contacts mounted on composite brush part being tested which is connected to power supply through switch, resistor, and current meter; potential contacts connected to voltage meter are mounted on same part. Current contacts are made in the form of disks with pointed rims or whist brooms mounted on disk rims; they are placed on working surface of layers whose second leads are interconnected; potential contacts are installed at radial length of layers and made in the form of disks with pointed rims; resistors and current meters connected to current contacts are made for each layer separately and insulating screens are placed between current through part of brush and voltage drop across this part is measured, this being followed by determining brush parameters and resistance. Current of equal magnitude is passed through each layer of brush; leads are interconnected, current contacts are connected to second leads of layers; voltage drop is measured at equal distances on radial length of layers or one of layers is assumed as common one and connected to one lead of power supply through resistor and current meter while second lead of power supply is connected to remaining layers through separate resistors with current meters; here voltage drop is measured across each layer at equal currents in them and equal distances between potential contacts connected to voltage meter. EFFECT: improved measurement accuracy. 7 cl, 3 dwg