Radk Hydro is an enterprise with 20 years of experience in servo valve R&D. It has established long-term servo valve maintenance and repair business with more than 35 end-user enterprises. At the same time, it maintains cooperation with more than 30 servo valve repair centers around the world, providing them with MOOG servo valve repair parts. If you also have servo valve repair or spare parts needs, please contact us.
1.Servo valve not working (no flow or pressure output)
– Broken external leads of the servo valve;
– Solder joint detachment of the electric plug of the servo valve;
– Moldy or broken coil, or broken (or short-circuited) internal leads of the servo valve;
– Inlet or return oil not connected, or wrong connection of inlet and return oil ports of the servo valve.
2.Servo valve output flow or pressure too large or uncontrollable
– Uneven surface of the servo valve mounting seat, or improper installation of the bottom seal ring, causing deformation of the servo valve housing and jamming of the valve core;
– Blockage of the servo valve control stage;
– Valve core stuck by dirt or rust.
3.Servo valve responds slowly, response decreases, zero offset increases
– Low system oil supply pressure;
– Too dirty internal oil filter of the servo valve;
– Partial blockage of the servo valve control stage;
– Loose mechanical components of the zero adjustment mechanism or torque motor (force motor) of the servo valve.
4.Output flow or pressure (or actuator speed or force) cannot be continuously controlled
– System feedback disconnected;
– System positive feedback occurs;
– System clearance, friction or other nonlinear factors;
– Poor resolution and increased hysteresis of the servo valve;
– Too dirty hydraulic oil.
5.Servo system jitters or vibrates (high frequency)
– Too large system open-loop gain;
– Too dirty hydraulic oil;
– A large amount of air mixed in the hydraulic oil;
– System grounding interference;
– Poor power supply filtering of the servo amplifier;
– Increased noise of the servo amplifier;
– Poor insulation of the servo valve coil;
– External leads of the servo valve touch the ground;
– Poor insulation of the electric plug;
– Intermittent blockage and unblocking of the servo valve control stage.
6.Servo system slows down (low frequency)
– Too dirty hydraulic oil;
– System limit cycle oscillation;
– Large friction of the actuator;
– Unstable zero position of the servo valve (loose internal screws or mechanisms of the valve, unlocked external zero adjustment mechanism, or dirt in the control stage);
– Poor resolution of the servo valve.
7.External oil leakage of the servo valve
– Excessively high surface roughness of the mounting seat;
– Dirt on the surface of the mounting seat;
– Improper installation or missing installation of the bottom seal ring;
– Broken or aged bottom seal ring;
– Broken bellows of the servo valve.