How to Maintain the Main Contacts
Functions
 A Fixed contact B Movable contact |
The main contacts of the device:
The movable contacts make (close) or break (open) the electrical circuit under normal conditions (at rated current In) or fault conditions (overload and short-circuit). |
Degradation Factors
The factors which can cause degradation of the main contacts are the following:
-
Frequent switching operations at rated current
-
Stresses due to high short-circuit currents
Potential Hazards
Performing regular maintenance on the main contacts can help to avoid the potential hazards and consequences listed in the following table.
|
Hazard |
Consequence |
|
|---|---|---|
|
Personal injury |
Equipment damage |
|
|
Fire |
Death or serious injury |
– |
|
Thermal dissipation due to high-resistance contact |
– |
Degradation of the breaking unit |
Preventive Action
The following table lists the preventive maintenance procedures to be performed to maintain the main contacts of the device.
|
Maintenance program |
Preventive action |
Procedure |
|---|---|---|
|
Standard end-user preventive maintenance |
Check the condition of the breaking unit. |
Breaking unit NIII_2_1 |
|
Manufacturer preventive maintenance |
Measure the contact resistance for each pole. |
Contact your Schneider Electric field service representative. |
For more information, refer to Preventive Maintenance Programs.