Service Bulletin: SB 200.1
Subject: Main Drive Motor Brake Springs — Air Operated (Wichita) Brakes
If, at any time, your plant air pressure approaches 60 psi, at the machine, PMC recommends changing the main drive motor brake from the current spring load to six springs. This would eliminate any chance of the release air pressure being overridden by the spring pressure. Because this is a holding brake, there must be no brake engagement until after the drive has stopped the machine. Low plant air pressure could partially engage the brake causing wear and premature failure. With six springs, the air pressure would have to fall well below the machine’s minimum pressure to even partially engage the brake.