Question 1

Resistors on starters with three or more steps of acceleration limit the current inrush to percent at the point of initial acceleration.&#10;A)110&#10;B)130&#10;C)150&#10;D)170

Accepted Answer

Resistors on starters with multiple steps of acceleration limit the current inrush to 150% at the point of initial acceleration. Resistors on starters with three or more steps of acceleration limit the current inrush to 150% at the point of initial acceleration.

Question 2

The operation of accelerating contactors is controlled by a timing device.

Accepted Answer

The operation of accelerating contactors is typically controlled by a timing device in order to gradually increase the voltage or current to a motor, rather than applying it all at once. The operation of accelerating contactors is controlled by a timing device, typically a motorized cam timer or electronic timer.

Question 3

A wound rotor motor can be reversed by interchanging any two stator leads.

Accepted Answer

Reversing the direction of a wound rotor motor, like any three-phase induction motor, can be achieved by swapping any two of the three stator leads. This changes the direction of the rotating magnetic field, thereby reversing the motor's direction.

Question 4

The wiring of the accelerating starters and the design of the resistor sections are meant for speed regulation.

Accepted Answer

The primary purpose of the wiring of accelerating starters and the design of the resistor sections is to control the starting current and protect the motor during startup, not for speed regulation. Speed regulation involves controlling the motor speed during normal operation, which is typically achieved through other means.

Question 5

Accelerating timers may be used to control the acceleration of wound rotor motors.

Accepted Answer

The answer of Accelerating timers may be used to control...

Question 6

Frequency relays have the advantage of .&#10;A)being easy to replace&#10;B)a simple circuit&#10;C)being nonrenewable&#10;D)slow response

Accepted Answer

Frequency relays often have a simple circuit design, which is advantageous for reliability and ease of maintenance.

Question 7

The secondary resistance consists of banks of three uniform sections.&#10;A)X&#10;B)star&#10;C)delta&#10;D)wye

Accepted Answer

The answer of The secondary resistance consists of banks of...

Question 8

The operation of a(n) timer is based on the applied load.&#10;A)accelerating&#10;B)compensated&#10;C)driven&#10;D)TR

Accepted Answer

A compensated timer is designed to adjust for changes in the load being controlled, ensuring more accurate and consistent timing. A compensated timer adjusts the timing based on changes in the load, making it more accurate and reliable than timers that are not compensated. The other options are not related to load-based timing.

Question 9

Frequency relays have the advantage that an increase in motor load prolongs the starting time.

Accepted Answer

Frequency relays sense the frequency of the motor and adjust the starting time accordingly. As the motor load increases, the frequency decreases, and the starting time is prolonged to avoid overloading the motor. Frequency relays monitor and control the frequency of the electrical supply to the motor. An increase in motor load causes a drop in frequency, and the frequency relay will extend the starting time to ensure that the motor is not overloaded at startup.

Question 10

When a 60-hertz AC, wound rotor motor is accelerated, the frequency induced in the secondary circuit decreases from 60 hertz at zero speed to hertz at full speed.&#10;A)2 or 3&#10;B)4 or 5&#10;C)6 or 7&#10;D)8 or 9

Accepted Answer

At zero speed, the frequency of the induced current in the secondary circuit of a wound rotor motor is the same as the supply frequency, which is 60 hertz. As the motor accelerates to full speed, the relative motion between the rotating magnetic field and the rotor decreases, reducing the frequency of the induced current in the rotor. At full speed, the rotor is moving in sync with the magnetic field, and the frequency of the induced current in the secondary circuit drops significantly, typically to 2 or 3 hertz, indicating very little slip between the rotor and the magnetic field.

Deck 36: Automatic Acceleration for Wound Rotor Motors