Description
The overvoltage protector PSNP is a combination of a mechanical switching element with manual reset and a bipolar thyristor stage. The PSNP is used like a voltage-limiting device to protect against inadmissibly high contact voltages.
Its task is to dissipate dangerous electric potentials and if necessary to switch the upstream switchgear off. The advantage in comparison to a voltage-limiting device is that no component must be replaced and the PSNP can be reset manually after triggering, in order to achieve its operating state again. A built-in potential-free micro switch can signal the response of the PSNP.
A further advantage is obviously the very compact design of the PSNP. The device can be installed practically anywhere with its dimensions of HxWxD 250x140x150mm.
The PSNP does not require regular maintenance. The device can be checked at any time by removing the cover and triggering the manual release.
The performance characteristics are persuasive notwithstanding the compact design:
0.3s 10kA
10s 4kA
42s 2kA
25min 1000A
Continuous current 750A.
The symmetrical tripping voltage (e.g. 8963-100 for DC ±100V) can be selected from various permanently set values when ordering (see ordering data).
The 3ms closing time of the main contact is considerably less than the requirements of the standard EN50122-1.
Occurring transient overvoltages (µs range) are intercepted by the thyristor stage up to a current of approx. 20A and do not lead to the main contact being triggering.
In practice, this prevents the device tripping frequently.
The thyristors are closed again when the potential difference reaches zero volt.
