Motor Control 3: Lesson 7 - Controlling Synchronous, Stepper, And Servo Motors

Question 1

Three-phase motors typically have slip, which is the difference between the rotational speed of the rotor of the motor and the rotational speed of the magnetic field in the stator of the motor. What is the slip of a synchronous motor?

a. 0 (zero)
b. 3%
c. 5%

Answer 1

a. 0

Question 2

______ in synchronous motors have two winding types, salient pole windings and amortisseur windings.

a. Rotors
b. Stators

Answer 2

a. rotors

Question 3

The ______ windings in a synchronous motor dampen speed fluctuations and allow the synchronous motor to operate as an induction motor until synchronous speed is achieved.

a. amortisseur
b. salient pole

Answer 3

a.
amortisseur

Question 4

When a synchronous motor is connected to 3-phase power lines in parallel with other AC motors with lagging power factor, the synchronous motor will ______ the power factor of the circuit.

a. have no effect on
b. improve
c. reduce

Answer 4

b. improve

Question 5

The ______ motor is a 3-phase motor in which the rotor turns at the same speed as the magnetic field of the stator.

a. servo
b. stepper
c. synchronous

Answer 5

c. synchronous

Question 6

The ______ motor converts electronic digital pulses into mechanical rotational steps.

a. servo
b. stepper
c. synchronous

Answer 6

b. stepper

Question 7

The ______ motor is a position or motion correcting motor that is driven to a specific angular position as commanded by a control signal.

a. servo
b. stepper
c. synchronous

Answer 7

a. servo

Question 8

For a stepper motor with an angular resolution of 1.8° per step, indicate the number of discrete steps required to achieve complete 360° rotation of the shaft.

a. 4
b. 200
c. 500

Answer 8

b. 200

Question 9

For a stepper motor with an angular resolution of 90° per step, indicate the number of discrete steps required to achieve complete 360° rotation of the shaft.

a. 4
b. 200
c. 500

Answer 9

a. 4

Question 10

For a stepper motor with an angular resolution of 0.72° per step, indicate the number of discrete steps required to achieve complete 360° rotation of the shaft.

a. 4
b. 200
c. 500

Answer 10

c. 500

Question 11

Match the motor functions to the term that best describes that function.

• The maximum amount of torque provided by a load that a stepper motor can withstand without moving from its position, with the stator energized.
• The maximum amount of torque provided by a load that a stepper motor can withstand without moving from its position, with the stator de-energized.
• The maximum number of steps the motor makes in one second.
• The number of degrees that the motor moves per step.

Choices:
- Detent Torque
- Holding Torque
- Stepping Rate
- Step Angle

Answer 11

Holding Torque - - The maximum amount of torque provided by a load that a stepper motor can withstand without moving from its position, with the stator energized.

Detent Torque - - The maximum amount of torque provided by a load that a stepper motor can withstand without moving from its position, with the stator de-energized.

Stepping Rate - - The maximum number of steps the motor makes in one second.

Step Angle - - The number of degrees that the motor moves per step.

Question 12

A typical hybrid stepper motor has ______ rotor teeth and rotates at a ______ step angle.

a. 100 / 3.6°
b. 200 / 1.8°
c. 400 / 0.9°

Answer 12

b.
200 / 1.8°

Question 13

Identify the parts on the servo motor control system to indicate the function of each component.

Answer 13

Question 14

What type of servo motor is typically used in computer related devices, numerically controlled machines, or other applications where starts and stops are made quickly and accurately?

a. AC servo motor
b. DC servo motor

Answer 14

b. DC servo motor

Question 15

What type of servo motor is used for rapid positioning in industrial applications where low inertia is present?

a. AC servo motor
b. DC servo motor

Answer 15

AC servo motor

Question 16

In most modern servo motor controls, ______ have replaced servo amplifiers as the controlling system.

a. personal computers
b. PLCs
c. servo motor controllers

Answer 16

c. servo motor controllers

Question 17

The servo motor controller consists not only of an amplifier, which drives the servo motor to the correct position, but also contains circuitry that receives signals from sensors, controls the system, and sends signals to a PLC that typically controls many servo systems.

True or False

Answer 17

true