Rotary tunnelling tool drive - comprises DC motor with one constant ratio reduction gear and speed adjustable by rectifier

摘要

The driving mechanism is for use with a rotary mining or tunnelling tool, and comprises a direct-current motor (8), with only one reduction gear (7), of constant ratio, between it and the tool (6). The motor can be shunt-wound, its speed being adjustable by altering the excitation voltage, using a rectifier, and it can also have an auxiliary series winding, and a compensation winding. The design gives high output as nearly constant as possible, automatically matching torque and speed.