ABB Power Distribution
23
8
Application of the X-ray regulations
One of the physical properties of vacuum
insulations is the possibility of X-ray emissions
when the contact gap is open. The specified type
test performed by the Physikalisch-Technische
Bundesanstalt (PTB) in Brunswick demonstrates
that the local dosage output of 1
µ
Sv/h at a
distance of 10 cm from the touchable surface is not
exceeded.
The results are as follows:
• The use of the vacuum interrupters at rated
voltage is completely safe.
• The application of the rated power frequency
withstand voltage specified for the switching
devices by DIN VDE 0670 and IEC 60056 is also
safe.
• Higher voltages than the rated power frequency
withstand voltage or DC test voltage specified in
DIN VDE or IEC standards must not be applied!
• Fulfilment of the above requirement 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).