Question 1

Two-wire control devices are generally designed to handle large currents.

Accepted Answer

Two-wire control devices are typically low voltage devices used for controlling circuits, and are not designed to handle large currents. Two-wire control devices are typically used for low-voltage and low-current applications, such as controlling lighting or small motors. They are not designed to handle large currents.

Question 2

Two-wire controls may be connected to operating coils of magnetic switches.

Accepted Answer

Two-wire controls can be connected to the operating coils of magnetic switches to control the circuit. Two-wire controls can be connected to operating coils of magnetic switches, allowing for remote or automatic control of the switch. The two wires typically control the flow of electricity to the coil, allowing it to activate or deactivate the switch.

Question 3

-volt motors require more contacts than the one contact usually provided on two-wire devices.&#10;A)24&#10;B)110&#10;C)120&#10;D)230

Accepted Answer

Higher voltage motors (such as 230 volts) require more contacts for safety and functionality purposes. A single contact on a two-wire device may not be enough to properly handle the high voltage and current of a 230-volt motor. Therefore, choice D is the best answer. 230 volt motors typically require more contacts than the one contact provided on two-wire devices. This is because they often require additional connections for control circuitry or safety features.

Question 4

Typical control voltages are 120 and volts.&#10;A)6&#10;B)8&#10;C)12&#10;D)24

Accepted Answer

Typical control voltages are 120 and 24 volts. 120 volts is a common control voltage for industrial and commercial applications, and 24 volts is a common control voltage for residential and small commercial applications. Choices A, B, and C are less common for control voltage applications.

Question 5

A two-wire control may be any type of switch having a graduated position.

Accepted Answer

A two-wire control is a simple control circuit that only has two wires connecting it to the control circuit. It typically uses a selector switch or push-button switch that has only two positions (on/off), not a graduated position. A two-wire control is a simple switch that only has two positions, on and off. It does not have a graduated position.

Question 6

The permits the use of intrinsically safe systems in areas that contain hazardous vapors.&#10;A)NEMA&#10;B)NEC&#10;C)IEEE&#10;D)UL

Accepted Answer

The National Electrical Code (NEC) provides guidelines for safe electrical installations and is widely adopted in the United States. Article 504 of the NEC specifically addresses intrinsically safe systems and their use in hazardous locations. NEC (National Electrical Code) contains guidelines and requirements for the installation and use of electrical systems in hazardous locations. It includes specific rules for intrinsically safe systems, which are designed to prevent ignition of hazardous vapors. NEMA (National Electrical Manufacturers Association) is a trade organization that develops standards for electrical equipment, but it does not have authority in regulating hazardous locations. IEEE (Institute of Electrical and Electronics Engineers) is a professional association for electrical and electronics engineers, but it does not regulate hazardous locations. UL (Underwriters Laboratories) is a certification organization that tests and verifies the safety of electrical equipment, but it does not regulate hazardous locations.

Question 7

A two-wire control may be a toggle switch.

Accepted Answer

A toggle switch can be used as a two-wire control where one wire is connected to the power source and the other wire is connected to the load. Toggling the switch will open or close the circuit, controlling the load. A two-wire control can be achieved using a toggle switch, where one wire is the hot wire and the other wire is connected to the load. Toggling the switch will complete or break the circuit, turning the load on or off.

Question 8

Control systems that operate on volts are often used in hazardous areas.&#10;A)24&#10;B)120&#10;C)230&#10;D)240

Accepted Answer

Control systems that operate on lower voltages, such as 24 volts, are often used in hazardous areas because they produce less heat and have a lower risk of electrical arcing, which can ignite explosive materials. Higher voltages such as 120, 230, and 240 volts are more commonly used in non-hazardous areas. Control systems operating on 24 volts are often used in hazardous areas because low voltage is less likely to produce sparks that can ignite hazardous substances.

Question 9

In the case of a(n) , the thermal heaters open the overload contacts in the control circuit and de-energize the coil, thus stopping the motor.&#10;A)overload&#10;B)imbalance&#10;C)overflow&#10;D)disproportion

Accepted Answer

The description specifically mentions "thermal heaters open the overload contacts", indicating that the situation being described is an overload. The other options (imbalance, overflow, disproportion) are not relevant to the given scenario. The given scenario describes a situation where thermal heaters open the overload contacts in the control circuit, which is done in response to too much current flowing through the motor. This is commonly referred to as an "overload" condition. The other choices of "imbalance," "overflow," and "disproportion" do not accurately describe the situation.

Deck 17: Two-Wire Controls