Question 1

The rapid cooldown of an evaporator coil results in increased moisture removal.

Accepted Answer

When an evaporator coil cools down rapidly, it causes the moisture in the air passing over it to condense more quickly, leading to increased moisture removal.

Question 2

Some brushless DC motor circuit boards contain ____ that permit the air handler to be set for different operating conditions.&#10;A) magnetic switches&#10;B) pressure switches&#10;C) temperature switches&#10;D) DIP switches

Accepted Answer

DIP switches (Dual In-line Package switches) are commonly used in brushless DC motor circuit boards to provide different operating settings. These switches are small and can be easily set by the user or technician to specify various options such as speed, acceleration, direction, and braking. This allows for flexibility in the operation of the motor and accommodates different application requirements.

Question 3

____ air handlers permit the motor to operate at different speeds in accord with the demands of the system.&#10;A) Variable-speed&#10;B) Outdoor&#10;C) Low temperature&#10;D) High pressure

Accepted Answer

Variable-speed air handlers have a motor that can operate at different speeds based on the demands of the system. This allows for greater energy efficiency and more precise control over the system. Outdoor, low temperature, and high pressure air handlers do not necessarily have this feature.

Question 4

The factors that determine the amount of torque produced by the brushless DC motor are the same as those for any other electric motor.

Accepted Answer

The amount of torque produced by a brushless DC motor is determined by factors such as the number of poles, the strength of the magnets, the amount of current flowing through the windings, and the design of the motor's rotor and stator. These same factors apply to all other types of electric motors as well.

Question 5

Brushless DC motors can exhibit efficiency as high as 90%.

Accepted Answer

The answer of Brushless DC motors can exhibit efficiency as...

Question 6

The typical air handler is powered by a multispeed motor that can generally operate at two speeds.

Accepted Answer

The typical air handler is powered by a multispeed motor that can operate at more than two speeds, often including variable speeds to precisely control airflow.

Question 7

The brushless DC motor is controlled by a circuit board located in the air handler.

Accepted Answer

The brushless DC motor is controlled by a circuit board located in the air handler.

Question 8

The ____ receives the information necessary to control the operation of the motor.&#10;A) coaxial connector&#10;B) control connector&#10;C) DIN connector&#10;D) power connector

Accepted Answer

The control connector typically carries signals related to the operation of the motor, such as speed, direction, and start/stop commands. The other connector options listed (coaxial, DIN, power) are not typically used for motor control signals.

Question 9

The brushless DC motor contains a ____, a stator, and the electronics necessary to change direct current into three-phase alternating current.&#10;A) permanent magnet alternator&#10;B) permanent magnet induction generator&#10;C) permanent magnet rotor&#10;D) neodymium magnet

Accepted Answer

The brushless DC motor contains a permanent magnet rotor, which is what creates the magnetic field to drive rotation. The stator and electronics convert DC to AC in order to power the motor. Option A refers to an alternator, which is a device that converts mechanical energy into electrical energy. Option B refers to an induction generator, which is used to generate electricity by using a rotating magnetic field to induce electrical current in a stationary coil of wire. Option D refers to a type of magnet that is commonly used in motors, but does not describe any specific component of the brushless DC motor. Therefore, the best choice is C.

Question 10

____ variable speed air handlers are operated at a low speed continuously to maintain air circulation throughout the dwelling at all times.&#10;A) Very few&#10;B) Some&#10;C) Many&#10;D) All

Accepted Answer

Many variable speed air handlers are operated at a low speed continuously to maintain air circulation throughout the dwelling at all times.

Deck 18: Brushless Dc Motors