Woodward UG-10D 8521-0312 | Engine/Turbine Speed ​​Controller, Industrial Grade

Product Overview

The Woodward UG-10D (part number 8521-0312) is an enhanced analog controller belonging to the Woodward UG (Universal Governor) series. Despite the increasing popularity of digital governors (such as the 2301A and 505E), the UG-10D remains important in a large number of existing systems and cost-sensitive applications due to its simple circuitry, fast response, no programming requirement, and high robustness.

Its operating principle is based on the classic PID (Proportional-Integral-Derivative) analog circuit:

Speed ​​Detection: An AC voltage signal is generated by a magnetic pickup unit (MPU) installed near the flywheel ring gear, with the frequency proportional to the engine speed;

Signal Processing: After internal rectification and filtering, the signal is converted into a DC voltage and compared with the “target speed” set by a local potentiometer or a remote 4–20 mA signal;

Error Amplification: The deviation signal is processed by the PID network to generate a control output;

Actuator Drive: The output signal is sent to an electro-hydraulic servo valve (such as the 2000-2010 series) or an electric actuator to regulate the fuel/steam supply.

⚠️ Note the difference:

UG-10: Basic type, only local potentiometer setting;

UG-10D (i.e., 8521-0312): The “D” indicates support for remote analog setting (4–20 mA), suitable for applications requiring remote speed control via DCS or PLC. Technical Specifications

Table

Item | Parameter

Manufacturer | Woodward Inc. (USA)

Complete Model | UG-10D

Part Number | 8521-0312

Power Supply | +24 VDC (typical), range 18–32 VDC

Speed ​​Input | MPU sensor (50 mV–150 VAC, frequency 10–5000 Hz)

Setpoint Input | Local potentiometer or 4–20 mA (isolated, switchable)

Control Output | ±10 VDC (50 mA max) or 4–20 mA (jumper configurable)

Control Mode | Speed ​​control (Isochronous) or Droop control (0–5% adjustable)

Adjustable Parameters | Gain, Stability, Dead Band, Start Ramp

Protection Rating | IP20 (suitable for installation inside control cabinets)

Operating Temperature | -20°C to +70°C

Dimensions | Approx. 160 mm × 90 mm × 50 mm (W×H×D)

Core Features and Advantages

✅ Flexible switching between two setpoint methods

The setpoint can be selected via internal jumpers between a local potentiometer or 4–20 mA remote setting, adapting to systems with different levels of automation.

✅ Droop control supports parallel operation

When multiple generator sets are running in parallel, enabling Droop mode allows for automatic load sharing without communication, eliminating the need for complex synchronization controllers.

✅ High noise immunity design

Utilizes a shielded enclosure and filtering circuits for stable operation in strong electromagnetic interference environments (such as near frequency converters).

✅ Software-free, plug-and-play

Fully hardware-based analog adjustment, no programming or PC required; commissioning can be completed on-site using knobs, significantly reducing maintenance complexity. Typical Application Scenarios

Standby/Main Generator Sets: Stable speed control of diesel generators (50/60 Hz)

Marine Power Systems: Main or auxiliary engine speed control, in conjunction with Woodward actuators

Industrial Compressors/Pumps: Maintaining constant speed to ensure process flow

Small Gas Turbines: Used as a primary speed controller, in conjunction with higher-level protection systems

Installation and Commissioning Notes

MPU Installation Clearance: The distance between the sensor face and the gear tooth tip is typically 0.5–1.5 mm; excessive clearance can lead to loss of low-speed signals.

Power Supply Filtering: It is recommended to install a TVS diode and LC filter at the 24V power input to prevent damage from startup surges.

Output Matching: If driving an electro-hydraulic valve (such as 2000-2010), ensure that the UG-10D output current capability meets the valve core requirements (add a power amplifier if necessary).

Droop Setting: When operating in parallel, the Droop percentage of all units must be consistent (usually set to 3–4%).

Grounding Specifications: Signal ground and power ground should be connected at a single point to avoid ground loops introducing interference.

Lifecycle and Replacement Recommendations

The UG-10D (8521-0312) is currently in its mature phase, and Woodward still provides limited support, but has recommended that users transition to digital products:

Direct Upgrade Options:

Woodward 2301A-LC: Digital speed controller, supports Modbus, CAN, compatible with UG-10D mounting dimensions

Woodward EasyGen-3000: Integrated speed control + protection + parallel operation all-in-one solution

Purchasing Recommendations:

If used for critical spare parts, it is recommended to purchase 2–3 units at once, as there is a high risk of future discontinuation;

Beware of refurbished parts on the market – genuine UG-10D casings are die-cast metal, with clear labels and smooth knob damping. We (Shenzhen Changxin) are a long-term supplier of genuine Woodward 8521-0312 UG-10D governors. Each unit undergoes:

Power-on functional testing (speed input → output response)

4–20 mA setpoint accuracy verification

Simulated parallel operation Droop characteristic verification

We provide a 12-month warranty and free application technical support to help you ensure the stable operation of your power system.

Technical Summary (English):

The Woodward 8521-0312 (UG-10D) is an analog electronic governor for diesel, gas, and steam turbines. It provides precise speed control via local or 4–20 mA remote setpoint, with adjustable droop for load sharing. Featuring robust analog circuitry and ±10 VDC output, it’s ideal for generator sets, marine propulsion, and industrial drives where simplicity and reliability are critical.