Watt Knot Arrestors

Features: � Widest protection range in the industry - from 550 volts to 5,600 volts � Provides protection for single-phase, 2-wire or 3-wire submersible motors and controls � Provides protection for three-phase submersible motors and controls � Provides protection for jet pumps or centrifugal pumps and controls � Installs along incoming power line, protecting the system � External placement allows replacement without removing the pump � Provides line to line and line to ground protection � Meets latest agency listing safety standards; NFPA 70 NEC, UL1449, 3rd Edition and CSA 516 requirements for a Type 2 Surge Protective Device How the Watt-Knot Works When a lightning or voltage surge of 500 volts or more reaches the Watt-Knot, the metal oxide within the plastic casing begins conducting the surge to ground, relieving the electrical pressure to the motor and control. Regular operation is resumed as soon as the surge is passed to ground. About Voltage Surges Research shows that only a small percentage of surges in domestic water systems are the result of near lightning strikes. Power outages, interference and voltage surges, frequently less than 3,000 volts account for a majority of power related motor burnouts. Damaging voltage surges can be caused by the opening and closing of switches (switching loads) and by lightning. Voltage surges created by switching loads may be 5.5 times the line voltage (1,265 volts on a 230 volt system and 2,420 volts on a 440 volt system). Brownouts, blackouts, and line interference also create similar surges. Generally, lightning-surge arrestors built into pump-motors do not offer adequate protection from switching loads. Their �spark-over� or �bleed-off� values range from 2,200 volts to 4,500 volts. At these high voltage ratings built-in arrestors allow surges to reach the sensitive insulation of motor windings. Since the average range of a voltage surge is 500 volts to 2,000 volts, internal lightning arrestors would not begin to work until voltages extend above 2,000 volts.