Customer Support Electric

DocumentID : 01-001166 Page 1 / 4 Last update : 18.05.2005

Inspection of Siemens mainbreakers type 3WN6

1) Introduction

Following information from our subsupplier concerning the inspection of installed mainbreakers, to be considered during next maintenance stop. Basically all types of installed mainbreakers should be inspected during annual maintenance stops !

2) Original information from Siemens (excerpt)

Between July 1999 and July 2004 you purchased circuit-breakers of type 3WN6 frame size I/ 3-pole (listed below) from us. After successful completion of all required tests, these circuit-breakers were delivered to you in perfect condition.

Both the evaluation of our product monitoring data as well as the quality inspections accompanying production have shown that the long term stability of one of the components can be affected due to changes in the structure of the material.

During the service life of the circuit-breaker this could lead to limited functionality of the circuit-breaker if inspections are not carried out according to the operating instructions. Failure to carry out the inspection could lead to serious personal injury / and , or property damage.

Since the longevity and application safety of our circuit-breakers is very important to us, we would like to remind you of the proper adherence to the mandatory inspections in order to avoid faults and repairs:

a) At least once a year or b) After every 1000 switching operations or c) after every severe shutdown

During the next inspection please particularly observe the following:

The indication pins for contact erosion on the respective poles serve as the main indicators of the proper functionality of your circuit-breaker. As long as these three pins on the contact carriers are visibly the same length as stipulated in the operating instructions, the circuit-breaker is operable. This is also the case if the three movable contacts move into the same position when the circuit-breaker is switched OFF.

If there are any distinct deviations from this specified condition of the indicators, we request that you contact us so that we can arrange an appointment for preventive maintenance work to be carried out on the circuit-breaker.

We strive to maintain the highest possible level of quality of our products. We therefore request your assistance and look forward to hearing from you or the operators of the affected 3WN6 circuit-breakers in the near future.

We would like to thank you in advance for your assistance.

Customer Support Electric

DocumentID : 01-001166 Page 2 / 4 Last update : 18.05.2005

3) Concerned types and series of mainbreakers (1999-2004)

All mainbreakers within the ident number range from 3190707001 to 3240709013 should be checked accordingly. Please refer to section 4) explaining how to find the idend number on the mainbreaker.

Following mainbreaker types were mainly installed in our production lines:

3WN6 031 0DB58 3KA1 ... 3WN6 031 7DH56 3HA1 ... 3WN6 131 0EB58 3KA1 ... 3WN6 231 0FB58 3KA1 ... 3WN6 331 7GH56 3HA1 ... 3WN6 421 0HB56 3HA1 ... 3WN6 431 0HB58 3KA1 ...

Basically all installed mainbreakers should be checked during every annual maintenance stop or earlier if another condition according to section 2 applies. For other types of mainbreakers please refer to operation and maintenance manual. Also consider to check mainbreakers delivered with equipment from other suppliers.

4) How to find the ident number of the mainbreaker ?

Customer Support Electric

DocumentID : 01-001166 Page 3 / 4 Last update : 18.05.2005

5) Checking the contact erosion

Before working on mainbreaker refer to operation manual for safety instructions !

6) Finding the indicator pins

Customer Support Electric

DocumentID : 01-001166 Page 4 / 4 Last update : 18.05.2005

7) Checking the indicator pins