Voith DSG-BXX113 - User Manual

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Summary

Technical Data

Ambient conditions

Specifies environmental parameters for storage and operation, including temperature and protection rating.

Electric Data

Details electrical specifications such as supply voltage, power consumption, and setpoint input.

Hydraulic data

Outlines hydraulic parameters including input pressure, fluid type, viscosity, purity, and leakage rates.

Safety Information

Definition of notes and symbols

Explains danger, warning, and note symbols to ensure safe handling and operation.

Proper use

Describes the intended function of the I/H converter for transforming electrical signals into hydraulic pressure.

Important notes

Provides crucial general safety advice for accident prevention, including handling pressure and electrical connections.

Functional Description

Design

Illustrates the internal components of the I/H converter, including control magnet, tappet, and control piston.

Packing, Storage and Transport

Packing

Describes the special packaging used for delivery and sealing of hydraulic connections.

Storage and preserving

Details surface protection, internal preservation, and storage duration recommendations.

Transport

Warns about improper transport and advises on secure packing to prevent damage.

Commissioning

Test run

Details steps for verifying the I/H converter's operation after installation, including checks and pressure settings.

Parameter setting

Explains how to adjust potentiometers X0 and X1 for optimal converter function and recommends documenting settings.

Operation

Operation with manual knob

Describes how to operate the converter using the manual knob, including removing the circlip and setting direction.

The I/H Converter, Type DSG-BXX113, is a sophisticated device designed to transform an electrical set signal into a proportional hydraulic output pressure. This functionality is crucial for applications requiring precise hydraulic control, such as adjusting control pistons in hydraulic cylinders that position steam turbine valves. The device operates by converting an electrical input into a magnetic force, which then acts on a control piston to regulate hydraulic pressure.

Function Description

The core function of the I/H converter revolves around the precise conversion of an electrical set signal (w = 4...20 mA) into a magnetic force (FMag) within its Control Magnet VRM. The limits of this magnetic force can be finely tuned using X0 and X1 potentiometers. This magnetic force is then transmitted via a tappet to the control piston. Opposing this magnetic force is a hydraulic force (FHyd), which is directly proportional to the output signal pressure (PA).

When these two forces are balanced, the control piston is positioned in what is referred to as the "hydraulic center." In this state, the output signal pressure (PA) accurately corresponds to the set electrical signal. The control piston maintains this equilibrium by performing minimal oscillating movements within the guiding edges of the P→PA and PĀ→T areas, ensuring the output pressure PA remains at the value set by FMag.

Should the set signal increase, leading to a rise in FMag, the control piston's position shifts. This shift connects the output pressure PA to the feed pressure P, while simultaneously blocking PA from the tank return lines T1 and T2. Consequently, the pressure PA increases until it forces the control piston back to the "hydraulic center," at which point PA again matches the new set signal. A spring force (FFed) generated by the control spring provides a force-offset, ensuring the I/H converter can function effectively even for output pressures near 0 bar. Any internal leakage within the system is efficiently directed back into the tank return line T2.

Usage Features

The I/H converter offers flexibility in operation, allowing for both electrical and manual control.

Operation with Set Signal: When the 24VDC supply voltage is switched on, the output signal pressure can be continuously adjusted by the 4...20 mA set signal. The range of this adjustment is defined by the settings of the X0 and X1 potentiometers. The X0 potentiometer adjusts the minimum output pressure (PA min) at a setpoint of 4 mA, with clockwise rotation increasing the pressure. The X1 potentiometer adjusts the maximum output pressure (PA max) at a setpoint of 20 mA, also with clockwise rotation increasing the pressure. It is important to adjust X1 before X0, as the X1 adjustment influences X0. The device is factory-adjusted according to the order specifications.
Operation with Manual Knob: For situations where an electrical connection is not available or desired, the I/H converter can be operated manually. A manual operation knob, located on the control magnet, allows for the setting of an adjustable spring force. This spring force, instead of the magnetic force FMag, acts on the control piston via the magnet armature and tappet. The hydraulic force FHyd, proportional to the output signal pressure PA, still opposes this manually set spring force. This feature enables the adjustment of output pressure without an electrical connection. To engage manual operation, the circlip must be removed from the manual operation knob. Turning the knob clockwise increases the output pressure. Upon completion of manual operation, the knob should be returned to its final counter-clockwise position, and the circlip re-inserted. It is important to note that manual operation, particularly with sudden adjustments, may lead to uncontrolled stroke movements of the hydraulic components controlled by the I/H converter output due to rapid increases in the output signal pressure.

Maintenance Features

To ensure trouble-free and reliable operation, the I/H converter requires regular inspection, maintenance, and repair.

Routine Inspection: This involves checking all pipes, screw connections, and connections on the I/H converter for any signs of leakage, impurities, or damage. Any identified issues should be rectified immediately during appropriate operating modes. The control behavior of the I/H converter should also be monitored for any changes, and causes analyzed and eliminated as needed.
Scheduled Inspections:
- After approximately 740 operating hours / max. 1 month: An oil sample should be taken from the oil tank and analyzed for solid and suspended matters, water content, shadings, and air bubbles. The oil's purity should be assessed, and if necessary, the oil should be cleaned or exchanged during an appropriate operating mode.
- After approximately 8000 operating hours / max. 1 year: A chemical analysis of an oil sample from the oil tank is recommended. If required, the oil should be cleaned or changed during an appropriate operating mode. Additionally, the electric connections of the I/H converter should be checked and retightened if necessary.
Troubleshooting and Remedial Action: The manual provides guidance for common malfunctions, such as pressure variations. Causes like air inclusions, low or varying input pressure, dirt particles, or pressure on the return line are addressed with specific remedies. For instance, during initial commissioning or after long periods of inactivity, air inclusions can cause pressure variations. To mitigate this, the input pressure should be connected first, followed by a five-minute wait before switching on the supply voltage to aid auto-ventilation. Contaminated pressure fluid can lead to increased friction and hysteresis, requiring cleaning of inner elements or replacement of the I/H converter if surfaces are damaged. If output pressure adjustment is possible manually but not with the control magnet, it indicates a defective control magnet VRM.
Shutdown Procedures: When the I/H converter is to be switched off for repair, inspection, or unit shutdown, the oil supply system must be turned off, and all pressure reservoirs relieved. The 24 VDC supply voltage should be disconnected, and all lines and piping removed. Care must be taken to collect any leaking oil in a suitable container for proper disposal. All openings should then be closed, and the I/H converter cleaned and packed.
Disposal: At the end of its service life, the I/H converter must be disposed of according to local environmental protection regulations. The device primarily consists of steel, copper, synthetic materials, electronic components, and residual oil.