Reyrolle LMT Retrofit Solution

Siemens has a strong heritage of expertise across transmission and distribution and with the latest LMT retrofit circuit breaker; you can be sure of the highest quality solution and service.

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Seamless interface

The LMT retrofit has been specifically designed for customers to seamlessly interface with their existing Reyrolle panels replacing outdated oil or SF₆ circuit breaker units with a modern vacuum circuit breaker. This can be a simple retrofit to extend life and minimise maintenance requirements or as part of a comprehensive upgrade to enhance the ratings of installed equipment.

Serving the market

Reyrolle installed 66,000 LMT units worldwide and it is estimated that 40,000 are still in service. In support of this, the LMT retrofit can be applied to the complete installed base of LMT, LSR, LMV, LMVP, and LMR equipment types.

Your benefits at a glance

Siemens SION vacuum devices require minimal maintenance, very high switching durability of vacuum, no oil or gas to handle.

Extending the life of switchgear up to 25 years.

Minimum disruption and site works required, no modifications necessary to shutters or cable boxes.

Total cost and time evaluation shows considerable advantages over replacement in many high density distribution applications and also critical industrial applications.

Type tested in actual panel types in accordance with IEC 62271-200.

In most cases equipment can be available six weeks following order receipt.

Short circuit ratings up to 31.5kA can be achieved. Additional extension panels and / or protection and control upgrades if required.

Added value services

A key part of any retrofit project is the added value services that we can provide. We are pleased to offer the following directly from the Siemens Service Centre, UK, Reyrolle Works:

Construction and mode of operation of SION cassette

The vacuum switching technology, proven and fully developed for more than 30 years, serves as arc- quenching principle by using vacuum interrupters.

The phase assemblies consist of the vacuum interrupters and the phase shrouds. The vacuum interrupters are air-insulated and freely accessible. The phase assemblies are fixed on the mounting plate of the operating mechanism and supported by means of the phase shroud. The vacuum interrupter (3) is mounted rigidly to the upper interrupter support. The lower part of the interrupter is guided in the lower interrupter support, allowing axial movement. The phase shroud (4) absorbs the external forces resulting from switching operations and the contact pressure.

The whole operating mechanism is mounted on its mounting plate, including the motor, releases, indicators and actuating devices. Stored-energy operating mechanism. The operating mechanism is a stored-energy spring mechanism.

The force is transmitted from the operating mechanism to the phase assemblies via operating levers. The closing spring can be charged either electrically or manually and latches automatically in when charging is complete. The closing spring acts as a stored-energy mechanism.

To close the breaker, the closing spring can be unlatched either mechanically by means of the local “ON” pushbutton or electrically by remote control. The closing spring charges the contact-pressure / opening springs as the breaker closes. The now discharged closing spring will be charged again automatically by the mechanism motor.

The breaker is now capable of performing the OPEN – CLOSE – OPEN operating sequence that is required for an unsuccessful auto-reclosing operation on the system side. All stored energy mechanisms perform the switching duties of synchronizing and rapid load transfer as well as auto-reclosing.

SION vacuum circuit-breakers have a tripfree mechanism according to IEC 62271-100. In the event of an opening command being given after a closing operation has been initiated, the moving contacts return to the open position and remain there even if the closing command is sustained.

This means that the contacts of the vacuum circuit-breakers are momentarily in the closed position, which is permissible according to IEC 62271-100.

The motors for charging the closing spring operate in short-time duty. Therefore the voltage and power consumption might differ from the data of the rating plate.

Technical Data

Rated Normal Current
630 A
1250 A
2000 A
Rated Voltage
12 kV
Rated Lightning Impulse Voltage
12 kV
Rated Power Frequency Withstand Voltage
28 kV
Rated Short Circuit Breaking Current
20 kA
25 kA
25 kA
Rated Short Circuit Making Current
50 kA
63 kA
63 kA
Rated Short Time Current
20 kA for 3s
25 kA for 3s
25 kA for 3s