The automatic control of a system is intended to ____.

• maintain the working conditions of the equipment with a controllable device

• evaluate overloading situations

• maintain stable or constant conditions without excessive human interference

• maintain safe operations for service technicians

Modulating controls are used to ____.

• start motors

• stop motors

• vary the speed of a motor

• stop the flow of a liquid

When a control is required to control space or product temperature, it is called a ____.

• safety device

• thermostat

• pressure control

• speed control

A thermal system overload may occur if a specific electrical or mechanical component is not cooled properly, resulting in ____.

• underload

• failure

• stagnation pressure

• overheating

Devices, such as thermostats, that open and close their contacts during the ____ operation of the system are referred to as operational controls.

• normal

• initial

• most recent

• final

The compressor in the refrigerator has a protective device that keeps it from overloading and damaging itself. This device is called a(n) ____.

• overload

• capacitor

• mass control

• speed control

The metals most often used in a bimetal temperature control are ____.

• copper and brass

• copper and steel

• brass and steel

• brass and aluminum

An example of a bimetal device is a ____.

The Bourdon tube ____.

• straightens out with an increase in voltage

• curls inward with an increase in vapor pressure

• straightens out with an increase in electrical current

• straightens out with an increase in vapor pressure

A thermocouple is a device that ____.

• converts heat to mechanical movement

• converts heat to fluid flow

• converts heat to electrical energy

• couples two temperature controls together