Power Supply and Control
Trace heat cables may be connected to single-phase or (in groups) to three-phase power supplies. Power is controlled either by a contactor or a solid-state controller. For self-regulating cable, the supply must furnish a large warm-up current if the system is switched on from a cold starting condition. The contactor or controller may include a thermostat if accurate temperature maintenance is required, or may just shut off a freeze-protection system in mild weather.
Electrical heat tracing systems may be required to have earth leakage (ground fault or RCD) devices for personnel and equipment protection. The system design must minimize leakage current to prevent nuisance tripping; this may limit the length of any individual heating circuit.
Read more about this topic: Trace Heating
Famous quotes containing the words power, supply and/or control:
“I swear by the mighty power of Amon-Ra, whose anger can shatter the world, and by the dread power of Set, that I will never betray my trust as High Priest of Karnak.”
—Griffin Jay, Maxwell Shane (1905–1983)
“With girls, everything looks great on the surface. But beware of drawers that won’t open. They contain a three-month supply of dirty underwear, unwashed hose, and rubber bands with blobs of hair in them.”
—Erma Bombeck (20th century)
“I candidly confess that I have ever looked on Cuba as the most interesting addition which could ever be made to our system of States. The control which, with Florida, this island would give us over the Gulf of Mexico, and the countries and isthmus bordering on it, as well as all those whose waters flow into it, would fill up the measure of our political well-being.”
—Thomas Jefferson (1743–1826)