Vermeer’s T-755 hydrostatic tracked trencher combines toughness with technology. The powerful machine is designed for digging in rock, cross-country trenching or working drainage and utility projects on roadways. The T-755 cuts trenches as deep as 10 ft and 14- to 36-in. wide at chain speeds of 397 to 724 ft/min. These operations and more are monitored and controlled by Vermeer’s Smarttec electronic control system for versatility and ease of operation. The system also records key functions for proactive maintenance and operator performance analysis. Its software provides real-time operator prompts based on operating conditions.
Vermeer’s T-755 hydrostatic trencher uses a low-speed, high-torque motor fed by two pumps to drive its trenching chain. Although it’s shown here cutting into dirt, it’s just as capable digging into rock using rotary, carbide-tipped cutters.
Traction and Trenching Circuits
The T-755’s dual-path hydrostatic drive, powered by a 275-hp @ 2,200-rpm diesel engine, uses a matching pump, hydraulic motor, and planetary transmission in a separate circuit for each track and is capable of full counter-rotation. A 4-pad pump drive box transmits torque and rotational speed to a pair of pumps that supply the traction and another pair powers the low-speed, high-torque trenching motor. Maximum transport speed for the 37.5-ton machine is 170 ft/min, with digging speeds from 0 to 91 fpm. Practical cutting speed ranges from 400 to 670 fpm, depending on the application and operating conditions. The machine’s service brakes also are hydrostatic, parking and emergency brakes are spring-applied, hydraulically-released.
But the T-755 really gets down to business with its digging chain with rotary, carbide-tipped cutters, which is powered by a single low-speed, high-torque hydraulic motor in a hydrostatic circuit supplied by two variable-displacement pumps through a control manifold. Even though maximum system operating pressure is set at 2,500, the motor can accept intermittent peak pressures as high as 6,000 psi, a condition that is not unusual when digging in rock. Two variable-displacement pumps provide the design flow to the motor; the Smarttec control regulates their displacement in unison. The dual-pump arrangement can deliver full engine power to the chain when needed.
Read more: Hydrostatic Trencher can Dig Automatically