KCG-3-350D-Z-M-U-H1-10 KCG-3-100D-Z-M-U-H1-10 Eaton Proportional Relief Valve 350 bar

Product Overview

⚠️ Brand Attribution Note: The KCG-3 series proportional relief valves were originally developed by Vickers, later acquired by Eaton, and are now manufactured and sold under Danfoss Power Solutions. Products sold under any of these brands are technically identical with 100% direct interchangeability.

The KCG-3 series electro-hydraulic proportional relief valves are single-stage proportional relief valves engineered by Vickers for industrial hydraulic systems. These are open-loop, single-stage valves designed to regulate hydraulic system pressure in proportion to an applied electrical input.

The KCG-3 can be used for direct pressure control in low-flow systems, or as a pilot stage for larger pressure control valves. The valve responds to variations in current supplied to its solenoid—increasing current raises the pressure setting, while decreasing current lowers it. KCG series valve design ensures low hysteresis and good repeatability.

This product range covers the following models:

• KCG-3-350D-Z-M-U-H1-10: Pressure range 6–350 bar, NG6, 24V DC solenoid, no manual override, DIN 43650 connector

• KCG-3-100D-Z-M-U-HL1-10: Pressure range 3–100 bar

• KCG-3-100D-Z-M-U-H1-10: Pressure range 3–100 bar

Our complete range of KCG-3 proportional relief valves strictly adheres to OEM technical standards, achieving 100% direct interchangeability with original components. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring performance parameters are fully consistent with genuine Vickers/Eaton/Danfoss products. Direct replacement significantly reduces equipment downtime and maintenance costs.

⚠️ Model Code Decoding:

• KC = Proportional Pressure Relief Valve

• G = Subplate Mounted

• 3 = ISO 4401-03 (NG6 / NFPA D03) mounting interface

• 350 / 100 = Maximum controlled pressure range (350 bar / 100 bar)

• D = Design series (1* series)

• Z = No manual override

• M = Metric interface

• U = DIN 43650 / ISO 4400 electrical connector

• H1 = 24V DC solenoid coil

• 10 = Design number (10–19 series share identical mounting dimensions)

Technical Specifications 

KCG-3 Series General Specifications (based on Eaton/Vickers technical data)

• Product Series: Vickers/Eaton/Danfoss KCG-3 series proportional relief valve

• Product Type: Electro-hydraulic proportional relief valve

• Valve Type: Single-stage, pilot-operated

• Maximum Operating Pressure: 350 bar (5075 psi)

• Maximum Flow Rate: 5 L/min (1.3 US gpm)

• Mounting Interface: ISO 4401-03 (NG6 / NFPA D03)

• Coil Voltage: 24V DC

• Coil Current: 1.6 A

• Coil Resistance: 7.3 Ω

• Electrical Connection: ISO 4400 / DIN 43650 connector (U-type)

• Seal Material: Buna-N

• Body Material: Ductile Iron

• Operating Temperature Range: -20°C to +60°C

• Ingress Protection: IP65

• Mounting Type: Subplate mounted

• Recommended Cleanliness: ISO 4406 Code 17/15/12

• Weight: Approx. 1.73 kg (3.82 LB)

Model Pressure Range Overview

• KCG-3-350D-Z-M-U-H1-10: Controlled pressure range 6–350 bar, max flow 5 L/min

• KCG-3-100D-Z-M-U-H1-10: Controlled pressure range 3–100 bar, max flow 5 L/min

• KCG-3-100D-Z-M-U-HL1-10: Controlled pressure range 3–100 bar, with HL1 configuration

Key Technical Advantages

1. Electro-Hydraulic Proportional Control for Stepless Pressure Regulation

The KCG-3 series regulates system pressure by varying the current supplied to the solenoid—increasing current raises the pressure setting, decreasing current lowers it. When paired with a Vickers PWM output stage proportional amplifier, it delivers high-precision stepless pressure control.

2. Low Hysteresis and High Repeatability for Consistent Control

KCG series valve design ensures low hysteresis and good repeatability. This makes the KCG-3 particularly suitable for automated pressure cycling applications in injection molding machines and presses.

3. Self-Bleeding Design for Simplified Installation and Consistent Performance

The KCG-3 features a self-bleeding design that simplifies installation and ensures consistent performance. When used as a pilot stage for larger relief or reducing valves, it delivers low minimum pressure combined with fast and stable step response.

4. Standardized Mounting Interface for 100% Interchangeability

The KCG-3 conforms to ISO 4401-03 (NG6 / NFPA D03) standard mounting interfaces. Valves of the same size across brands are physically and interface-wise identical, enabling 100% direct interchangeability without manifold modification or system adjustment.

5. Compact NG6 Design for Space-Saving Installation

The KCG-3 features NG6 (CETOP 3 / NFPA D03) size with compact footprint. With maximum flow of 5 L/min, it is ideal for direct pressure control in low-flow systems or as a pilot control stage for larger valves.

6. Rugged Industrial-Grade Design for Harsh Environments

The KCG-3 features a ductile iron body with Buna-N seals, operating temperature range -20°C to +60°C, and IP65 ingress protection. Suitable for machine tools, automated production lines, construction machinery, and other industrial applications.

7. 100% Simulated Operating Condition Testing

Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring consistent, stable performance at rated pressure and flow.

Application Areas

• Injection Molding Machinery: Proportional pressure control and automated pressure cycling for injection molding and blow molding machines

• Hydraulic Machine Tools: Stepless pressure regulation for CNC machines and machining centers

• Pressure-Controlled Pumps: Pilot control stage for pressure-controlled pumps

• Pilot Control of Large Relief/Reducing Valves: Low-flow pilot actuation of large pressure control valves

• Low-Flow Hydraulic Systems: Direct pressure control applications

• Automated Production Lines: General industrial proportional pressure control

• Test Equipment: Precision pressure control for hydraulic test benches

Expert Maintenance Tips

1. Must Use a Dedicated Proportional Amplifier

The KCG-3 series proportional solenoid requires specific PWM current drive—PLC direct voltage output cannot drive the solenoid. A Vickers/Eaton/Danfoss dedicated proportional amplifier (PWM output stage with output current control) is required. Input signals are typically 0–10V or 4–20mA.

2. Verify Model and System Compatibility Prior to Installation

The KCG-3 series offers 100 bar and 350 bar pressure range options. Confirm that the pressure range code (350/100) covers system operating pressure. The 350 model offers 6–350 bar control range, while the 100 model offers 3–100 bar.

3. Mounting Interface and Bolt Torque

The KCG-3 conforms to ISO 4401-03 (NG6) standard mounting interfaces. Use a torque wrench to tighten mounting bolts diagonally to the values specified in technical manuals to prevent valve body distortion or leakage.

4. System Cleanliness Management

The KCG-3 is a precision proportional valve demanding adequate oil cleanliness. Recommended system cleanliness: ISO 4406 Code 17/15/12 or higher. Install high-precision filters (filtration rating ≤10μm) in the system return line and inspect filter elements regularly.

5. Electrical Connection Precautions

• KCG-3 series solenoid requires 24V DC power supply, coil current 1.6 A, resistance 7.3 Ω

• Electrical connector type: ISO 4400 / DIN 43650

• Verify supply voltage matches coil specifications and observe correct polarity prior to wiring

6. System Commissioning and Calibration

• During commissioning, start from low command signals and gradually increase, monitoring system pressure response for smooth operation

• Input signal vs. output pressure exhibits a linear proportional relationship

• Vickers/Eaton/Danfoss recommended proportional amplifiers are recommended for optimal performance

7. Periodic Functional Checks

Perform functional checks every 2,000 operating hours or annually: verify linearity between command signal and output pressure, response time testing, leakage inspection, and hysteresis/repeatability verification. If reduced control accuracy, sluggish response, or abnormal leakage is observed, arrange for servicing or replacement.