WTI Sidewinder SW720A, Installation And Operation Manual

Page: 23 / 27

SURGE PROTECTION AND PRESSURIZATION
SURGE PROTECTION
The SW720A camera provides internal surge protection for all of the power, data and
video signals.
1.) The AC line power connections are provided with 275 volt 135 Joule MOV surge
arrestors rated for 6000 Amp pulses. A 3A SMT fuse is included in the primary
circuit to prevent catastrophic printed circuit board damage in the case of gross
AC line input overloads.
2.) The video signal lines incorporate a two stage protection circuit consisting of a
primary 90V gas discharge tube, followed by a high speed, low capacitance 6.2V
2kW peak power transient voltage suppressor.
3.) The data signal lines incorporate a two stage protection circuit consisting of a
primary 90V gas discharge tube, followed by an 18V, 300W, 40A transient
voltage suppressor.
SEALING AND PRESSURIZATION
The SW720A camera provides two levels of sealing and pressurization. The entire
camera, including the base, housing and camera tube are all sealed to IP66/67 levels to
prevent any ingress of dust or moisture. An additional option is available, in which the
camera housing tube is pressurized to 5 psi with dry nitrogen gas.
The SW720AP camera with the pressurization option is provided with a Schrader valve
to allow periodic replenishment of the dry Nitrogen in the camera housing tube. Since no
sealing system will remain 100% airtight indefinitely, it may be necessary to replenish
the dry Nitrogen occasionally. This can be done at the same time that the regular camera
cleaning is performed. A 15psi pressure relief safety valve is provided to prevent damage
to the seals and to prevent blowing out the front or back plates of the camera housing if
an unregulated high pressure dry Nitrogen tank were to be connected to the Schrader
valve
SW720A WTI ~ Page 23 of 27