stängningsspänning

Stängningsspänning, or closing voltage, refers to the voltage across a switch or circuit breaker at the moment it is closing. This voltage is generally lower than the system voltage due to the impedance of the conductors, any contact resistance in the closing contacts, and potential voltage drops across other components in the circuit. As the contacts close, the resistance decreases, and the voltage across the switch will approach the system voltage.

The magnitude of the stängningsspänning is influenced by several factors, including the design of the switchgear, the condition of the contacts, and the current flowing through the circuit at the time of closure. In some applications, particularly those involving high inductive loads, a phenomenon known as re-striking can occur during opening, where the arc may momentarily re-ignite. However, stängningsspänning is specifically concerned with the voltage present as the circuit is being intentionally closed.

Understanding stängningsspänning is important for the design and operation of electrical systems. It can affect the wear and tear on switch contacts and influence transient voltage phenomena. For instance, a high stängningsspänning can lead to increased erosion of contact surfaces, reducing the lifespan of the switch. Therefore, switchgear manufacturers aim to minimize this voltage to ensure reliable operation and longevity of their equipment. Precise measurement of stängningsspänning can be a diagnostic tool for assessing the health of switching devices.