TRAVEL CIRCUIT OPERATION TRAVEL MOTOR-LH TRAVEL MOTOR-RH R E D Speed change mechanism(auto) Counterbalance valve B(BW) DR2 DR1 Turning joint 189AK3HC21 Valves are provided on travel motors to offer the following functions. 1) COUNTERBALANCE VALVE When stopping the motor of slope descending, this valve to prevent the motor over run. 2) SPEED CHANGE MECHANISM (auto) Auto two speed control mechanism consists of two spools and spring. This valve automatically changes motor displacement in portion to motor pressure. 3-20 RH R E D A(FW) A(FW) B(BW) DR2