Electronic Switching for Ducted Systems

A range of switch boxes and switched blastgates which allow a remotely located extractor to be switched on and off by the operation of the blastgate on any one of the machines in the system. The switching is done via a low-voltage circuit which makes installation simple and totally safe. The most convenient method of installation is to run either standard 110mm soil pipe or 100mm metal ducting around the workshop and to drop spurs down to each of the machines. The soil pipe adaptors listed below are detailed elsewhere in this section. Blastgates are fitted directly onto the end of each spur and connections are made to the machines using lengths of flexible hose together with the appropriate adaptors as listed elsewhere in this section. Two switch boxes are available, the 990022 which takes a maximum load of 2kVA, and the 990021 for any machine in the WV range. It must be stressed that the blastgate switches should only ever be connected to the switch box and not be used to switch the extractor directly. To ensure that an excessive load is not applied to the workshop system the 990021 switch box slowly ramps up the power to the extractor rather than switching the unit directly on. In this way current surges are avoided and there is no apparent power loss to the machines, dimming of lights or throwing of trip switches.