The Effect of ‘Silt Lock’ on AC Solenoid Valve Coils

Hydraulic Solenoid Valve (Bosch Rexroth)

In true AC electric coils, the resistance or impedance of the coil is lowest when the solenoid is open, i.e. when the plunger is out. Impedance increases as the plunger is pulled into the closed position. As a result, the current draw of an AC solenoid is highest when the solenoid is open (plunger out) and lowest when the solenoid … Read more

Pump Leakage Constant and Volumetric Efficiency

Rexroth A2VSL1000 hydraulic pumpThe hydraulic pump is the hardest working component of a hydraulic system. And as the pump wears in service, internal leakage increases and therefore the percentage of output flow available to do useful work (volumetric efficiency) decreases. If volumetric efficiency falls below a level considered acceptable for the application, the pump will need to be changed-out. In a condition-based maintenance … Read more

5 Things You Must Tell a Hydraulic Machine Supplier

big question markWhen buying a piece of hydraulic equipment, there are 5 things about the environment the machine will operate in, that you should always disclose to the equipment supplier or designer–even if they don’t ask. Especially if they don’t ask:

1. Minimum and maximum ambient temperature. This information is necessary to determine the correct hydraulic fluid type, viscosity grade and … Read more