ABB VM1-T, Manual

Page: 20 / 44

VM1-T
- VACUUM CIRCUIT BREAKER 20
One of the physical properties of vacuum insulation
is the possibility of X-ray emissions when the
contact gap is open.
The specified test performed by the Physikalisch-
Technische Bundesanstalt (PTB) in Braunschweig
demonstrates that the local dosage output of 1
μSv/h at a distance of 10 cm from the touchable
surface is not exceeded when the rated voltage is
applied.
The results are as follows:
• Testing of the switching device or the vacuum
interrupter to VDE 0671 part 100 or IEC 62271-100
at the relevant rated power frequency withstand
voltage may only be performed by trained
personnel observing the stipulations of the EU
basic standard (Stipulation 96/29/Euratom of the
senate from 13 May 1996 (ABI.L 159 from 29 June
1996)).
• Application of the rated voltage specified for the
switching device by VDE 0671 part 100 or IEC
62271-100 is completely safe.
• Higher voltages than the rated voltage or DC test
voltage specified in VDE or IEC standards must
not be applied!
• The containment of the above mentioned local
dosage output with the vacuum interrupter in the
open position is dependent on maintenance of the
specified distance between the contacts (which is
automatically ensured with correct mechanism
function and force transmission).
• Safety clearances must be maintained.
—
8. Application of the X-ray regulations