D633K2050 D633K2051
D633Z303B D633Z305B
D633Z313B D633Z317B
D633Z338B D633Z348B
D633Z371B D633Z379B MOOG German made original control pressure and flow servo valve

FAQ;

What are the most common failures and how can they be diagnosed?

Common failures can be categorized by the valve's internal components :

• Torque Motor Issues:

◦ Broken Coils: Result in no current, valve does not respond.

◦ Contamination in Air Gap: Causes the armature to stick, preventing valve movement.

◦ Loose Fasteners or Worn Parts: Can lead to increased null bias or instability.

• Nozzle/Flapper Stage Issues:

◦ Clogged Nozzles or Orifices: Often caused by oil contamination, leading to reduced frequency response, poor resolution, and system instability.

• Spool Amplifier Stage Issues:

◦ Spool Sticking: Caused by contaminated oil or a deformed spool, resulting in distorted response or complete seizure.

◦ Cutting Edge Wear: Increases internal leakage, causes null shift, and reduces stability.

System-level symptoms caused by these failures include :

• Cylinder Refusal to Move: Often due to a stuck servo valve.

• Uncontrolled Valve Movement: Sudden full opening/closing of a cylinder without a command change, often due to a clogged nozzle.

• Cylinder Oscillation ("Cylinder Hunting"): Can be caused by high internal leakage, poor resolution, or instability in the valve's null zone.

• High Cylinder Lag.

7. How can I maintain my MOOG Servo Valve and prevent failures?

The most critical factor for reliable servo valve operation is maintaining clean, dry hydraulic fluid .

• Oil Filtration: Use high-quality filters and adhere to a strict oil analysis and replacement schedule. Contamination is the primary cause of servo valve failure.

• System Design: The hydraulic system should be designed to minimize dead spots where contaminants can accumulate. The reservoir should be sized appropriately to allow for air and contaminant separation .

• Regular Inspection: Periodically check the valve and system for leaks, unusual noises, or changes in performance.

• Preventive Maintenance: Follow the manufacturer's recommended maintenance intervals, which may include replacing the valve's internal filter (if equipped) .

Purchasing and Services

8. Can I get a specific valve that is not listed in your standard catalog?

Yes, MOOG is known for its ability to provide custom solutions. They can modify product components to enhance performance or meet specific application requirements .

Quanzhou Yisenneng Hydraulic Electromechanical Equipment Co., Ltd. has been established for many years and has now developed into an international trading company supplying various hydraulic machinery parts, oil pumps and valves. We are one of the few Chinese companies with multiple products and channels. Main focus: quality assurance! The price is the lowest in the industry! Quality management procedures are implemented in accordance with international standards and are implemented throughout the production process. In terms of channels, we have gathered the most complete variety of products in the world; in terms of quality, all products meet international standards; the lowest price in the industry is the highest; the fastest delivery on credit, and a complete after-sales system; remember Good service is the key to cooperation with customers. We strive to achieve high quality standards, provide competitive prices, and ensure timely delivery. In this way, our products have been recognized by the market and satisfied by customers in the past years. Our goal is to meet the needs of our global customers. Here you can enjoy a one-stop shopping experience, the customer is God, you want all of us, I wish you a happy shopping trip.