FEMA Offers High-Quality Direct Drive Proportional Valves
FEMA is featuring its Direct Drive Proportional Solenoid Valves in September 2021. Included are low-frequency hydraulic solenoids which are direct drive proportional valves with two, three and four way pressure or position control. Operating at cycle rates of 40 to 300 Hz, low frequency valves (LFV) are used for Transmission, PTO, Brake and SCV controls as well as brake cooling. The solenoid armature in FEMA’s LFVs is directly coupled to the valve spool, with the spool driven by the force from the armature. LFVs are a relatively smaller package with an integrated, wet coil for heat dissipation, and come with a sealed connector.
Direct drive valves differ from 2 stage pilot valves in that the solenoid armature is directly coupled to the valve spool. Thus the valve spool is driven solely by the force generated from the armature itself. Direct drive valves are simpler, have no quiescent flow, are generally smaller, but have less driving force than 2-stage valves. To improve performance in contaminated fluid medium, FEMA direct drive proportional valves utilize a fine mesh filter on the sleeve ports in order to keep damaging debris out of the metering area. Whereas our 2-stage valves are rated as high as ISO 29/23, FEMA direct drive valves are rated up to ISO 25/20. Since most hydraulic systems operate at or below levels of ISO 19/16, FEMA direct drive valves are more than adequate to exceed performance needs.