1790-789 Woodward overspeed protector

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Product basic information
Manufacturer: Woodward
Model: 1790-789
Belonging to the famous 505 series
Supports multiple communication protocols and can be smoothly integrated with the existing control system of the factory
Core application: Designed specifically for speed control and protection of steam turbines
1790-789 controller has stable performance and high reliability

Categories: WOODWARD
Tags: - Actuator 1790-789 controller debugger module Motor touch screen WOODWARD

1790-789 Woodward overspeed protector

The 1790-789 is a microprocessor-based digital governor controller produced by Woodward, belonging to its classic 505 series.
It is primarily designed for speed control and protection of steam turbines. Below is a detailed introduction to this product:

I. Product Overview

Brand and Model: Woodward 1790-789
Series: 505 Series Digital Governor
Type: Microprocessor-based controller
Purpose: Specifically designed for steam turbines to control their speed and provide overspeed protection.

II. Core Functions

Speed Control:
- 1790-789 Precisely controls the speed of steam turbines by adjusting steam inlet flow.
- Supports single-range or split-range actuators to accommodate turbines of different sizes.
Overspeed Protection:
- Incorporates triple independent overspeed protection logic to ensure rapid shutdown in case of overspeed, preventing equipment damage.
- Provides an overspeed test button for convenient on-site testing of protection functions.
Emergency Shutdown:
- Equipped with an emergency stop button for immediate shutdown in emergency situations.
System Protection:
- - Automatically switches control modes upon sensor failure to ensure uninterrupted system operation.
  - Offers local/remote control priority selection to adapt to different operational scenarios.

The function of stepper motor driver
A stepper motor driver is an actuator that can convert the electrical pulse signal it receives into angular displacement.

When the stepper motor driver receives an electrical pulse signal, it drives its stepper motor to rotate a fixed angular displacement (we call it the “step angle”)

according to the originally set direction. Its rotation is carried out step by step at a fixed angle. We can control the displacement of its angle by controlling the number of pulses it sends,

in order to achieve precise positioning; At the same time, we can also control the speed and acceleration of the stepper motor by controlling the frequency of its pulse signal, thereby achieving its

speed regulation and positioning goals. Widely used in various carving machines, crystal grinding machines, medium-sized CNC machine tools, EEG embroidery machines, packaging machinery,

fountains, dispensing machines, cutting and feeding systems, and other large and medium-sized CNC equipment with high resolution requirements.

The number of phases of a stepper motor refers to the number of coil groups inside the stepper motor. Commonly used stepper motors include two-phase, three-phase, four phase, and five phase.

The step angle of a regular two-phase stepper motor varies depending on the number of phases, with a step angle of 1.8 degrees for a three-phase motor, 1.2 degrees for a three-phase motor, and 0.72

degrees for a five phase motor. When there is no stepper motor subdivision driver configured, users mainly rely on selecting stepper motors with different numbers of phases to

meet the requirements of step angle. If a subdivision driver is used, the phase number will become meaningless, and users only need to change the subdivision number on the driver to modify the step angle.

After the subdivision of stepper motor drivers, there will be a qualitative leap in the operational performance of the motor, but all of this is generated by the driver itself and has nothing to do with the motor

and control system. When in use, the only thing that users need to pay attention to is the change of the step angle of the stepper motor, which will have an impact on the frequency of the step signal sent by

the control system. As the step angle of the stepper motor will decrease after subdivision, the frequency of the requested step signal should be correspondingly increased. Taking a 1.8 degree stepper motor as

an example: the step angle of the driver is 0.9 degrees in half step state, and 0.18 degrees in ten step state. Therefore, under the condition of requesting the same motor speed, the frequency of the step signal sent by the control system is 5 times that of half step operation in ten step state.

The accuracy of a regular stepper motor is 3-5% of the step angle. The deviation of a single step in a stepper motor does not affect the accuracy of the next step, so the accuracy of the stepper motor does not accumulate.

III. Technical Specifications

Power Supply: 18-32 VDC, supporting 24VDC input.
Display: Two-line x 24-character LED display for clear indication of operating status and parameters.
Enclosure: NEMA 4X or IEC 60529 IP56 rated for protection against harsh industrial environments.
Inputs/Outputs:
- Inputs: 6 programmable current inputs, 16 discrete contact inputs.
- Outputs: 2 actuator outputs, 8 relay outputs, 6 programmable current outputs.
Communication Interfaces: 1790-789 Supports RS-232, RS-422, and RS-485 hardware interfaces for easy integration with host computers or other devices.
Software: Equipped with OpView™ and 505View software for parameter configuration, monitoring, and fault diagnosis.
Operating Temperature: -20 to +60°C (some models support -4 to +140°F).
Storage Temperature: -40 to +85°C (some models support -40 to +185°F).
1790-789 Weight: Approximately 9.11 pounds (4.13 kilograms).

IV. Application Scenarios

Steam Turbine Control: 1790-789Suitable for steam turbines of various sizes, including industrial steam turbines, small grid turbo-generators, and turboexpanders.
Single Extraction and Admission Applications: Designed for operating steam turbines in single extraction and/or admission applications.
On-Site Programming: Allows on-site operators to program and adjust parameters through an integrated operator control panel, adapting to different operating conditions.

V. Product Advantages

High Reliability:
- Microprocessor-based design ensures precise control and stability.
- Triple independent overspeed protection logic provides multiple layers of safety.
Flexibility:
- Supports various actuator and sensor configurations to accommodate different turbine models.
- Offers a rich set of input/output interfaces for easy system expansion and integration.
Ease of Use:
- Two-line x 24-character LED display provides an intuitive operating interface.
- A 30-key multifunctional keyboard simplifies parameter configuration and operation.
Compatibility:
- Supports multiple communication protocols for easy integration with DCS, PLC, and other systems.
- Provides OpView™ and 505View software for remote monitoring and fault diagnosis.