Motors ch-8 Flashcards
2.Assume that the overload contact is connected in parallel with the starter coil.what happens when the starter button is pressed?
The control fuse will probably blow
1.When a control component is connected in a circuit to perform the function of stop?
It is connected in series with the starting coil.
3.How is the amount of overload current set for a particular motor?
By changing the size of the overload heater.
4.When a control component is connected in the circuit to perform the function of Start?
It is connected in parallel with the start button.
5.To determine if the start pushbutton is good or bad with an ohmmeter continuity should be indicated when?
The button is pressed yes
The button is no pressed no
6.The coil of a motor starter has a resistance of 6 ohms but current flow of 0.1 a with 120 VAC applied. Is this normal and why?
Yes current is limited by inductive reactance not resistance.
7.Assume that the two stop push buttons are connected in parallel instead of in series.what is the action of this circuit?
Both stop buttons have to be pressed to de-energize the circuit
8.A stop push button?
Can be double-acting pushbutton with only normally closed section used.
9.assume that the two start pushbutton
Are connected in series instead of parallel.what is the action of the circuit?
Both start buttons have to be pressed to energize the starter coil.
10.when the start buttons 1 & 2 are pressed the motor does not start. Which of the following can cause this problem?
The overload contact is open
11.When start buttons 1&2 are pressed the starter energizes by t he motor does not run. Which of the following can cause this condition?
The motor stator winding is open
- Assume that the motor is operating. When the stop button 1 is pressed the motor continues to run. When the stop button 2 is pressed the motor stops running. Which of the following can cause this condition?
stop button 1 is shorted
13.When start button 2 is pressed the starter does no energize. When start button 1 is pressed the circuit does energize. Which of the following can cause this problem
The contact of start button 2 are not making connection when the button is pressed.
14.A voltmeter connected across start button 1 indicates 120v when the button is pressed. When the meter is connected across start button 2 it indicates 0v when pressed.what does this test reveal?
Start button 1 is defective
15.When either of the stop buttons are pressed the motor continues to operate normally. A voltmeter connected across either stop button indicates 120v when the button is pressed. What does this test indicate?
The load contacts are welded shunt.
16.Assume that the stop pushbutton 2 is incorrectly connected normally open. What is the action of the circuit?
The circuit can operate If stop button 2 is held down.
17.Assume that start button 1 was incorrectly connected normally close. What will be the action of the circuit?
The motor will start running as soon as power is applied to the circuit
- Assume that the normally open auxiliary contact is incorrectly connected in series with the stop button instead of in parallel with start buttons. What is the action of the circuit?
The circuit will not energize when either of the start button is pressed.
- The motor begins running when power is applied. If either stop button is pressed the motor stops. When the button is release the motor restarts.what can not cause this problem?
The over load contact is open
20.A voltmeter connected across the overload contact indicates full line voltage when start button 1 is pressed.the voltmeter indicates 0v when the start button is release. What does this test indicates?
The overload contact is open
