2027 Exams Includes Frequently Tested Questions With
ELABORATED 100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!! Current Update!!
Instant Download Pdf
1. Can you state the 5 functions of motor control? - Correct Answer: Start/Stop control
Motor and Circuit Protection
Speed Control
Jogging
Reversing
2. Do you know how low-voltage protection works? - Correct Answer: Manufactures
have developed manual motor starters that have a sensing coil that verifies the presence
of line voltage. The starter contacts open if the incoming line voltage is lost or drops
below a preset level.
3. Can you define the 3 types of motor overload devices? - Correct Answer: Thermal-
trips once a certain heat level is reached.
Magnetic- uses coils to monitor the motor current. Once it reaches an unsafe level, the
coil acts as a solenoid and pulls the core upward to open the motor starter's contacts.
Solid State- solid state overloads are very costly and therefore not as common. Solid
state overloads use a multitude of electrical components to more accurately measure a
motors current level.
4. Can you explain the operation of a two wire motor control circuit? - Correct Answer:
A two wire control circuit uses two wires to connect the input deice to the power supply
and to the coil of the magnetic starter.
, 5. When the contacts of the pilot device are closed, the current path to the coil is
completed and the coil is energized.
This causes the contacts of the magnetic starter to close and provide power to the
motor by connecting it to the power lines.
6. Can you explain the operation of a three wire motor control circuit? - Correct
Answer: A three-wire control circuit uses three wires to connect the input device to the
coil of the magnetic starter.
The third wire provides the seal-in or memory function.
7. Do you know two common control methods used to reverse a three-phase motor? -
Correct Answer: To reverse the direction of a three phase motor you can simply swap 2
wires. This being said, the industrial standard as recommended by NEMA and IEC is to
reverse motor connections T1 and T3.
The two most common ways to reverse a three-phases motor include a reversing
magnetic motor starter and a drum switch.
8. Can you explain the operation of a drum switch? - Correct Answer: A drum switch is
a manual switch that is used to change the direction of rotation of a motor by switching
the leads to a motor. A drum switch operates by changing the path for the electrical
power to flow through the switch.
9. Do you know three interlocking methods for a motor control circuit? - Correct
Answer: Auxiliary Contact Interlocking
Pushbutton Interlocking
Mechanical Interlocking
10. Do you know how a forward/reverse motor jog control circuit works? - Correct
Answer: A lock-stop is installed so when the stop button is mechanically held open, the
start button has to be held down.