Electrical surges due to lightning are common sources of sensor and data acquisition equipment failure. The lightning protection packages described below improve the likelihood of continued functioning of equipment exposed to frequent lightning storms, and these packages are highly recommended for systems in such locations. Protection against a direct lightning strike, of course, cannot be guaranteed.
Tower grounding kits use ground rods and copper cable or copper strips to conduct any electrical charges due to lightning directly to the ground. In the 190-121, a straight ground rod is mounted to the tower leg at the top of the tower. The 190-122 provides an angled rod, for use when wind sensors will be mounted on top of the tower. The 190-120 does not use a top-mounted ground rod, but uses 25 foot by 1-1/2 copper strips, clamps, and ground rods attached to each tower leg. The 190-110 is a low cost grounding kit designed for use with a tripod. Mounting hardware is included with each package. Ground cable must be ordered separately, except for the 190-110.
AC power lines to the junction box and to instruments on the tower are protected by the 350-1077 and 350-1077-A Secondary AC Power Surge Arrestors. When a surge occurs, these devices divert it to earth ground and immediately self-restore. The 350-1077 and 350-1077-A must be mounted in a junction box.
Sensor line surge arrestor packages protect the sensor signal lines and dedicated or switched telephone lines. Each package utilizes a two-stage transient suppressor. When a surge occurs, a zener diode clamps the voltage (24 Vdc) at a safe level and series resistors absorb the remainder of the voltage. A gas discharge tube is activated if the voltage is greater than 150 Vac. These components absorb the bulk of the transient and discharge it to earth ground. After the transient passes, the entire circuit recovers automatically. The 350-B380-24V protects four lines and the 350-B480-24V protects eight lines. Screw terminals are provided for input and output connections. These line arrestors are normally mounted in a junction box.
350-B480-24V Sensor Line Surge Protector
NovaLynx offers customized packaged units consisting of a junction box, surge board, ac protection, fused 115 Vac input/output circuits, ground rod, and ground cable. Consult the factory for a quotation.