Category: Woodward

The governors are available with either a cast-iron case or a die-cast aluminum case. 

Speed droop is required for stable governor operation. Droop is factory set, but internally adjustable. 

Two means of speed setting are available. Screw speed setting is standard. Lever speed setting is 

optional and provided by a serrated shaft assembly extending from both sides of the cover. 

Governor drive shaft rotation for both governors is single direction only. In both the cast iron and the die

cast aluminum governors, rotation can be changed in the field. In the cast iron governor, it must be 

changed internally, and in the die-cast aluminum governor, it can be changed externally by removing

four screws and rotating the pump housing 180 degrees (see Chapter 2). 

Governor maintenance is minimal due to few moving parts, weatherproof design, and self-contained oil 

supply. The governor drive shaft operates a gerotor oil pump. Internal oil pump pressure is regulated by

a relief valve/accumulator. The oil sight gauge installed on each side of the governor case makes oil 

condition and oil-level checking simple.

Description 

The Woodward TG-13/TG-17 and TG611-13/TG611-17 are mechanical-hydraulic speed droop governors 

for controlling steam turbines—applications where isochronous (constant-speed) operation is not 

required. 

The TG-13/TG-17 and TG611-13/TG611-17 governors have a full 40 degrees of maximum terminal-shaft 

travel. Recommended travel from the no load to the full load position is 2/3 of full governor travel. 

See Figure 1-1 for a graphic representation of maximum work capacity for the governors and related 

governor terminal shaft travel information. 

The TG-13/TG611-13 governor operates with 1034 kPa (150 psi) internal oil pressure, and the TG

17/TG611-17 operates with 1379 kPa (200 psi) internal oil pressure. 

Either governor is set to the speed range specified by the customer at time of order. The high-speed 

governor (4000 to 6000 rpm) may require a heat exchanger in some applications (see end of Chapter 2, 

“When is a Heat Exchanger Necessary?”). Both governors are capable of controlling at lower-than

specified speed range with some loss of output torque and performance. The governor should not be run 

at a speed greater than the range specified because of heat rise and component wear issues.

Features

The actuator output is an ISO 9409 flange. This allows for easy mounting of levers to

simplify replacement. The orientation of the output flange relative to the bracket base

is the same for each actuator. Additionally, the actuators are equipped with break-away

stops that prevent the actuator from exceeding the maximum output travel range

during setup. An output position indicator is standard.

The EM-80 and EM-300 systems include a mounting bracket with hole pattern. The

bracket design ensures that stresses in the actuator are reduced to a minimum.

Actuator specifications and performance are based on a system including bracket.

The actuators are equipped with a flying-lead position-sensor cable (including connector).

A position sensor cable connecting the actuator and the driver is available.

This cable is similar for both the EM-80 and the EM-300.

A single EM-driver is used for both the EM-80 and the EM-300. Only the software

setup for each actuator system differs. Monitoring, alarm, and diagnostics are available.

An EMI power filter is supplied to suppress emissions.

Optional Features

The EM-80 and EM-300 systems include a bracket for mounting on the engine or turbine.

A standard mounting hole pattern is provided. Alternative patterns are available on request.

Applications

The EM-80 and EM-300 are intended to be mounted on large diesel, gas, and

gasoline engines, and on all types of turbines, to control the position of engine fuel

racks, turbine fuel valves, turbine and turbocharger variable geometry, and to handle

timing control. These systems are well suited for engines without a mechanical drive

or hydraulic oil supply.

Description

The EM-80 and EM-300 are all-electric actuator systems that provide 40 degrees of

actuator output rotation. Each system consists of a three-phase brushless ac motor

which drives a high-precision planetary reduction gear box. A dedicated driver

controls the actuator position and allows monitoring of most features.

PC/Windows based software facilitates the system setup. The EM-80 and EM-300

are freely programmable to meet many customer requirements.

 Fast slew times

 Freely programmable

 Brushless servomotor and resolver

 Precision gearbox, high stiffness, low backlash

 CE marking

 Models with ABS, BV, and DNV certification

 Cost effective solution

The EM-80 and EM-300 actuators have different position-sensing systems. Both

systems use the same hollow shaft resolver, producing a sine and cosine wave

output with an overall accuracy of 12 arc-minutes. This resolver is mounted at the

rear of the motor and looks at the relative position of the motor shaft.

The EM-80 uses only the resolver since the 1:7 gear ratio within the gearbox

allows full stroke of the actuator output flange with less than one full revolution of

the motor shaft.

The EM-300 has a 1:20 gearbox ratio to achieve the required torque output.

Because of this, the motor shaft rotates more than one full revolution to achieve

full stroke. To ensure proper position indication over the full range, a 10-turn

potentiometer is added behind the resolver to supply a coarse position signal

from which the correct rotor revolution is deduced. The same resolver as used on

the EM-80 gives the accurate position within that revolution.

EM-80/-300 System Description

The EM-80/-300 system consists of an actuator, a driver, an AC line filter

(required for marine TN/TT only), and interconnection cables.

The EM-80 and EM-300 are all-electric actuator systems that provide a nominal

40° of actuator output rotation. Each system consists of a three-phase brushless

ac motor which drives a high-precision planetary reduction gear box. A dedicated

driver controls the actuator position.

Actuator

The actuator is available in two versions, offering two work output levels, EM-80

and EM-300. Both versions use the same three-phase brushless AC motor.

The difference in output is achieved by the use of two different gearboxes. The

EM-80 uses a single-stage planetary 1:7 gear ratio, while the EM-300 uses a

two-stage planetary 1:20 gear ratio.

The motor–gearbox combination comes assembled on a mounting bracket with a

fixed hole pattern. Although the EM-300 is longer than the EM-80. both use the

same mounting hole pattern, allowing the actuators to be interchangeable.

The output flange provides an easy mounting surface for a variety of lever

configurations, and is equipped with a rugged pointer and scale for quick output

position reference while working on the prime mover. A breakaway extension and

two stop pins form a simple means of detecting whether the actuator has been

driven outside its operating boundaries.

Introduction

This manual covers components of the EM-80/-300 Actuator System and does

not include operating instructions for the prime mover or the driven devices or

processes. For information about other Woodward products used in conjunction

with the EM-80/-300. please refer to the specific Woodward documentation

supplied with each product.

For specific operating information such as start-up, shutdown, and the prime

mover’s response to signals from the Woodward control, refer to the prime mover

manufacturer’s manual.

Description of Components

The EM-80/-300 system provides an all-electric actuation system for various

prime mover control applications.

The system is intended for use on large diesel, gas, and gasoline engines, and

on all types of turbines, to control the position of the engine fuel racks, turbine

fuel racks, turbine and turbocharger variable geometry, and to perform timing

control.

The EM Driver controls the EM-80/-300 Actuator position proportional to a

position demand signal received from a controlling device. The EM-80/-300

Actuator consists of a high-performance three-phase brushless ac motor that

drives a precision planetary gearbox.

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Hydraulic Filter Assembly

The valve is supplied with an integrated, high-capacity filter. The broad range filter protects the internal

hydraulic control components from large oil-borne contaminants that might cause the hydraulic

components to stick or operate erratically. The filter is supplied with a visual indicator which shows when

the recommended pressure differential has been exceeded and thus replacement of the element is

necessary.

LVDT Position Feedback Sensors

The SonicFlo control valves use a dual-coil, dual-rod LVDT for position feedback. The LVDT is factory set

to give 0.7 Vrms feedback at minimum position and 3.5 Vrms feedback at maximum position, when

supplied with 7 Vrms excitation at 3000 Hz.

Trip Relay Valve Assembly

The SonicFlo™ valve uses a solenoid-operated trip relay circuit to operate a high capacity, three-way,

two-position, hydraulically operated valve. This trip relay circuit consists of four functional elements: the

trip relay solenoid valve, the trip relay supply orifice, the hydraulically operated trip valve, and the trip

relay volume.

In the normal run mode, the trip relay solenoid valve is closed, which prevents the trip relay volume from

bleeding to the hydraulic return. As a result, high-pressure oil is fed into the trip relay circuit through the

supply orifice, which quickly pressurizes the trip circuit to supply pressure. When the trip circuit pressure

increases above 1100 kPa (160 psig), the three-way relay valve shifts position so that the common port

connects the control port of the servo-valve to the lower piston cavity of the actuator, allowing the servo

valve to position the throttle valve.

The solenoid valve opens when it is de-energized. Opening the solenoid valve causes the trip circuit to be

connected to drain. This in turn causes the three-way relay valve to shift position so that the common port

is connected to the hydraulic drain circuit, and isolated from the hydraulic supply. As the pressure falls

within the lower piston cavity, the return spring rapidly returns the valve plug to the downward position,

closing the control valve and shutting off fuel to the engine.