Hydraulic Accumulator Maintenance, Testing and Recertification

Bladder and diaphragm accumulatorGas-charged accumulators are a common feature of modern hydraulic systems. They carry out numerous functions. These include energy storage and reserve, leakage and thermal compensation, shock absorption and energy recovery. But while accumulators present a number of advantages in hydraulic system operation, and can provide many years of trouble-free service, they are a maintenance item.

For example, the correct gas … Read more

Is it OK to Connect Supply Voltage to a Proportional Valve Coil?

FTDRE-prop-press-reducerOne of our members wrote me this question:

“One of our customers has a new wheeled excavator. The auxiliary circuit on this machine is controlled by an electronic proportional foot pedal which sends its signal to an ECU. This ECU then sends a variable voltage to 2 proportional solenoids located on the auxiliary circuit sandwich on the main DCV. But Read more

Hydraulic Motor Drains: If In Doubt Connect It Out

While absolutely essential on a piston-type hydraulic motor, an external case drain line is usually optional on gear motor designs–external, internal and gerotor/geroller. These types of motors don’t have a large-volume case or sump like piston motors do. But they do have internal leakage which by design, usually accumulates in a small cavity just behind the shaft seal.

By installing … Read more