Relay Circuits - Final Exam
Print this page. The answer sheet is given at end of the exam. Enter your
answers on the answer sheet. No time limit. But 2 hours should be enough.
1. Generally speaking, a stop button is normally ______.
2. Generally speaking, a start button is normally ______.
3. What type contacts act as holding contacts? ______
4. When proper voltage is applied to a coil and nothing happens, what might be
the reason? ______
5. If line voltage is 120 volts what component is needed for control voltage to
be 24 volts? ______
6. Can the control voltage be higher than the line voltage? ______
7. Which leads are used from a step down transformer for control voltage? ______
8. Can a single phase electrical supply voltage control circuit be used to
operate a three phase load? ______
9. Which terminals are used on a three phase contactor for line side voltage?
______
10. Which terminals are used on a three phase contactor for load side voltage?
______
With reference to this diagram, answer questions 11 through 20.
11. Is the F coil dependent on R coil or independent? ______
12. Is the F coil dependent on CR coil or independent? ______
13. Can the F coil energize if R overloads are open? ______
14. Can the R coil energize if F overloads are open? ______
15. When power is first applied and no voltage is read across the FWD. push
button, what can be determined? ______
16. What is the line voltage across the F coil when energized? ______
17. When the CR relay is energized, what will the F coil be able to do? ______
18. When the CR relay is energized, what will the R coil be able to do? ______
19. In the run mode, what effect does the CR relay have on the circuit?
20. In the jog mode, what effect does the CR relay have on the circuit? ______
Use these answers for questions 21 through 30.
two wire control
OR
sequence
independent operation
21. Five motors can pump water into a tank. Only one can be on at any one
time. This is described as ______ operation.
22. A doorbell is wired to ring when the button is pressed. This is called
______ operation.
23. If one motor shuts off on overload, any other motor can run. This is called
______ operation.
24. Four motors can power a conveyor belt depending on load. The operator can
run any motor anytime. This is called ______ operation.
25. The air pump motor comes on based on temperature. This is called ______
operation.
26. A conveyor belt should only run when an operator holds down a pushbutton.
This is called ______ operation.
27. Motor 1 must be on before Motor 2 can come on. Motor 2 must be on
before Motor 3 can come on. This is called ______ operation.
28. A forward and reverse motor arrangement will not allow both to be on at any
one time. This is called ______ operation.
29. The three fill pumps at this apparatus can come on and go off individually
any time. This is called ______ operation.
30. A paper cutter blade will not actuate until the guard gate has been lowered.
This is called ______ operation.
31. What tool is needed to measure coil voltage? ______
32. What tool is needed to determine if contacts are no or nc? ______
33. What tool will give current readings? ______
34. What tool will determine resistance? ______
35. What tool will determine if a coil is open? ______
36. What is the description of this symbol? ______
37. What is the description of this symbol? ______
38. What is the description of this symbol? ______
39. What is the description of this symbol? ______
40. What is the description of this symbol? ______
Use this diagram to answer questions 41 through 45.
41. How are the overloads wired in this diagram? ______
42. How are the C contacts connected to points 2 and 3 described? ______
43. How are the C contacts connected to points 2 and 3 wired with reference to the start button? ______
44. Can the stop, start, and C coil and overloads be described as in series? ______
45. Can the stop button cause the C coil to deenergize when running? ______
46. Sketch a three wire control of M coil with a single stop and a single start.
L1 L2 120 volt ______(use answer sheet space)
47. Sketch a two wire control of M coil with a single start push button. L1 L2
120 volt ______ (use answer sheet space)
48. Sketch a forward reverse three wire control with a single stop, single
forward, single reverse with an electrical interlock. All overloads in series. L1 L2
120 volts ______ (use answer sheet space)
49. Sketch a forward reverse three wire control with a single stop, single
forward, single reverse, with an electrical interlock. Overloads separate. L1 L2
120 volts ______ (use answer sheet space)
50. Sketch a jog forward, run forward, jog reverse, run reverse with a selector
switch (jog/run) and a control relay. Electrical interlock. Single stop.
All overloads in series. L1 L2 120 volts ______ (use answer sheet space)
Relay Circuits - Answer Sheet
Use this answer sheet for your answers.
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45.
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