American Governor A Logo American Governor Logo & background picture
 
Home
Field Service
Tech Support
Training
Upgrades
Contact
 


Special Events
Governor School 2008
Focus Class: Mech Cab Actuators
Digital Governor Conversions
Mechanical Cabinet
Gateshaft
Other OEM Governors
HMI Systems
New Hydraulic Power Units
Woodward/GE
Digital Specialty Modules
Driver Amplifiers
PT Interface
Feedback Amplifier
501 & 517 DCS Series Controls
DCS Modules - 501 and 517 Series
Driver Amplifiers and Other Parts
MicroNet™ Series Controls
Micronet Modules
Other Replacement Parts
Mechanical Governor Parts
Mechanical Cabinet
Gateshaft Governor
GS Actuator
A Actuator
Pump Parts and Support
XX Herringbone Gear Pumps
Gateshaft 20 Series Pumps
IMO Pumps
Pump Electric Unloader Kits
Permanent Magnet Generators
PMG Parts
PMG Service
PMG Re-magnetizing
Speed Switches
Speed Switch Parts
Speed Switch Service
Analog-Electric Governor Parts
MOD I and MOD II Modules
Replacement Parts
Training Classes On Site
Factory Repair Service
AGC Product Brochures
Articles & Papers
Links to Our Vendors
Field Service
Technical Support
Contact Information
Careers at AGC

Digital Conversion – Gateshaft Governor

Our scope of supply typically includes equipment, engineering and site supervision. Each kit includes a PLC-based digital control cabinet with touchscreen local operator interface, pilot valve electro-hydraulic interface manifold, and electronic speed and gate position sensors.

Typical Gateshaft After Conversion
Typical Gateshaft After Conversion

The PLC cabinet can be physically mounted and wired by your staff or others using the drawings we provide. During the outage, an experienced Field Service Engineer will be on hand to assist with installation and provide final commissioning and testing services.

PLC Governor System

The heart of each new governor system will be an Allen-Bradley™ Programmable Logic Controller (PLC).

The new controller and accessories will reside in a wall-mount control enclosure that includes the following devices:

• Governor PLC
    (1) 7-slot PLC Rack
    (1) CPU Module
    (1) Power Supply Module
    (1) Contact Input Module – 16 channel
    (1) Contact Output Module – 16 channel
    (1) Analog Input Module – 8 channel
    (1) Analog Output Module – 4 channel
• Cabinet Power Supply (125VDC/24VDC)
• Terminal Blocks (as needed)
• Interposing Relays (as needed)

Typical PLC Governor Cabinet
Typical PLC Governor Cabinet
Shown with front door open

Local Operator Interface: Color Touchscreen

Mounted on the front door of the PLC Governor, a 6” color touchscreen Human Machine Interface (HMI) will serve as the primary Local Operator Interface. Local control screens described below will be provided by AGC and will allow operators full access to all system control modes.

The touchscreen operates independently and automatically establishes communication with the PLC Governor upon boot-up; no operator intervention is required and system screens are stored in non-volatile memory. HMI programming software and cable are included to allow you to modify or add new screens.

    • Local control of the unit
    • Local display of unit information
    • System Alarm display
    • Input / Output (I/O) Status display
    • Event log
    • Basic trending
    • Access to tunable parameters for the unit
    • Serial port for printing

In addition, a door-mounted Emergency Shutdown pushbutton will be provided.

Sample Unit Control Screen
Sample Unit Control Screen

Cabinet Power Supply

A 125VDC/24VDC cabinet power supply will be provided to power the Governor PLC, proportional valve, accessory equipment and field devices.

Electro-Hydraulic Interface (EHI) Assembly for Gateshaft Governors

The EHI assembly is the basic connection between the PLC Governor and the existing relay valve. The EHI controls the flow of oil to the relay valve, which regulates the flow of oil to the servomotor to open or close the wicket gates.

The assembly includes the following devices:

Proportional Control Valve
Enables servomotor control via PLC during normal operation. This high-response valve provides closed-loop control of distributing valve spool position.

Solenoid Shutdown Valve
Enables emergency shutdown independent of the PLC. When de-energized, the solenoid valve causes the distributing valve spool to move fully in the close direction, causing the servomotor to close at the fastest rate allowed by the stop nuts.

Hydraulic Manifold
A custom manifold for the mounting of valves. Includes shutdown shuttle assembly for independent shutdown via solenoid valve (blocks control flow from proportional valve).

Electro-Hydraulic Interface (EHI)
Electro-Hydraulic Interface (EHI)
Typical Gateshaft configuration shown

Primary Speed Signal

Primary speed sensing is done via an American Governor Speed Signal Module connected to a generator Potential Transformer. Our high-resolution Speed Signal Module provides one 0-200% analog output for metering and one high-resolution analog output for synchronizing and on-line droop control.

The module is compliant with IEEE 125 “IEEE Recommended Practice for Preparation of Equipment Specifications for Speed-Governing of Hydraulic Turbines Intended to Drive Electric Generators.” Back-up speed sensing is available as an option.

Before upgrading
Before upgrading

Relay Valve Position Feedback (LVDT)

The EHI requires an accurate and stable relay valve position signal in order to function closed-loop. A Linear Variable Differential Transformer (LVDT) will be provided for relay valve feedback.

Mounting hardware, signal conditioner and connector will be included.

EHI Assembly and LVDT
EHI Assembly and LVDT

Servomotor Position Feedback (MLDT)

The Magnetostrictive Linear Displacement Transducer (MLDT) is a superior non-contact alternative to traditional low-cost linear position feedback devices such as linear potentiometers or string pots. An MLDT will be provided for electronic feedback of Wicket Gate servomotor position.

Mounting hardware and connector will be included.

Gate Feedback MLDT
Gate Feedback MLDT

Assemble, Wire & Test

American Governor will assemble and wire the complete PLC governor system in Ivyland, PA. Your system will be connected to our Turbine Simulator, which will be programmed to mimic site conditions.

All hardware and software will be tested completely before leaving our factory.

PLC Control Software

American Governor will provide governor control software adapted from proven software algorithms. Typical functionality includes:

    • Automatic Start / Stop Control
    • Unit Speed / Frequency Control with Variable Droop
    • On-Line / Off-Line Gains
    • Remote On-Line Setpoint from Plant Control
    • Gate Limit Control
    • Maintenance-Manual Position Control
    • Automatic Pre-Load (To Prevent Reverse Power Condition)
    • Soft Loading & Unloading of Unit
    • Speed Switches and Gate Position Switches (as required)
    • System Alarm Indications
    • I/O and CPU Diagnostics

Whole system after conversion
Whole system after conversion

Home
Field Service
Tech Support
Training
Upgrades
Contact
© 1999 - 2008 American Governor Company & Bear Naked Web Design. All rights reserved.
NetCon™, GAP™, MOE™ and OPTrend™ are registered trademarks of the Woodward Governor Company