Silcostat / STHP — thyristor excitation system for synchronous generators and motors up to 6000 A
Silcostat (STHP in newer materials) is a thyristor AC to DC converter for supplying the field windings of synchronous machines. Supply voltage is below 1000 V, and the field current is up to 200, 2000 or 6000 A depending on cooling. It is used at thermal and hydropower plants and in industrial power plants.
- Type
- thyristor AC/DC converter (fully controlled Graetz bridge)
- Field current
- natural air cooling — up to 200 A; forced air — up to 2000 A (Silcostat — up to 3500 A); water — up to 6000 A
- Supply voltage
- < 1000 V AC
- Output
- direct current
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The Silcostat excitation systems, called STHP in newer materials, are built on thyristor AC to DC converters that supply current to the field windings of synchronous generators and motors. They regulate the voltage of synchronous generators and control the power of synchronous motors. During the refurbishment of large thermal and hydropower plants, replacing obsolete excitation systems improves the efficiency, performance and availability of generators. Both names in the documentation refer to the same line, so when selecting spare parts or a replacement it is worth comparing the technical parameters rather than the designations.
The power circuit is built on a fully controlled thyristor Graetz bridge. The supply voltage is below 1000 V AC, and the output is direct current, which is used to regulate the generator voltage or the motor power. The rated field current depends on the cooling method: up to 200 A with natural air cooling, up to 2000 A with forced air cooling, and up to 6000 A with water cooling using a water-to-water or water-to-air heat exchanger. For the Silcostat version, up to 3500 A is stated with forced air cooling, so the current limit for a specific generator must be confirmed. Natural cooling covers small field currents, forced air medium ones, and water cooling is intended for the largest machines.
According to the manufacturer, the excitation systems are designed to fit into any facility and work with equipment already installed. This increases generator availability and gives smooth dynamic performance. The manufacturer also produces brushless excitation systems for its own generators (a shaft-mounted exciter with a rotating diode bridge), supplies excitation and control systems for hydro generators during hydropower plant modernisation, and combines them with its own synchronous motors and Silcovert S (LCI) frequency converters. In such drives, rotor field control is coordinated with the inverter.
The current ratings determine which machine can be excited from a single system, from small synchronous motors with natural cooling to large generators with water cooling. The systems are used to excite synchronous generators of thermal and hydropower plants and industrial power plants, synchronous compensators and large synchronous motors. The manufacturer's quality management system is certified to ISO 9001:2015.
Technical specifications
| Type | thyristor AC/DC converter (fully controlled Graetz bridge) |
|---|---|
| Field current | natural air cooling — up to 200 A; forced air — up to 2000 A (Silcostat — up to 3500 A); water — up to 6000 A |
| Supply voltage | < 1000 V AC |
| Output | direct current |
| Cooling | natural, forced air, water with a water-to-water/water-to-air heat exchanger |
| Functions | voltage regulation of synchronous generators, power control of synchronous motors |
| Compatibility | integration with existing equipment during modernisation |
Request a price and lead time
Silcostat / STHP — thyristor excitation system for synchronous generators and motors up to 6000 A. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What field current can the system provide?
Depending on cooling, the current is up to 200 A with natural air cooling, up to 2000 A with forced air cooling and up to 6000 A with water cooling. For the Silcostat version, up to 3500 A is stated.
What supply voltage is required and what is the output?
The supply voltage is below 1000 V AC, and the output is direct current. The power circuit is built on a fully controlled thyristor Graetz bridge.
What machines and facilities is the system intended for?
For synchronous generators of thermal and hydropower plants and industrial power plants, synchronous compensators and large synchronous motors. It is also used when replacing obsolete excitation systems.
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