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Speed switch from simplifies stopping an over-speeding engine

08 July 2010

A speed switch, the RevGuard, has been added to the Chalwyn range of electronic engine control systems. This speed switch continuously monitors engine rpm and, should the engine rpm exceed a pre-set limit, transmits a signal to close the air intake shutoff valve to stop an over-speeding diesel engine.

Speed switch from simplifies stopping an over-speeding engine
Speed switch from simplifies stopping an over-speeding engine

Well proven on vehicles and stationary engines in the harsh Canadian climate, these compact and durable switches work with both 12 volt or 24 volt power and a choice of speed input options in one product. Encapsulated against fuel, moisture and dirt, they have a wide -30°C to +75°C operating temperature range, making them ideal for vehicles working in refineries or gas plants.

Engine speed is monitored either via a magnetic pick-up mounted on the engine's flywheel housing or a pulse signal from the alternator. Having automatic reset, a local trip indicator, screw terminals for easy installation and an aluminium frame for ruggedness, they are compatible with Chalwyn energized-to-stop SVX valves, or an air pressure system commonly found on larger trucks to activate a Chalwyn MPX or PVX intake shut off valve.

Functionality also includes a simple test button that temporarily reduces the trip point to two-thirds of the desired rpm limit, enabling initial installation and system tests without over-speeding the engine. The trip point is easily adjusted in the field, with a repeatability of less than 1% deviation, and there is provision for a remote test switch allowing demonstration of the system for a safety inspector.

Also available for Chalwyn butterfly valves are actuation kits that include components to make installation easier. Popular items in these kits include manual override switch, solenoid relay, circuit breaker and fittings for pneumatic systems. A new 'Systems Guide' booklet is available on request.


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