Answers and Explanations

  1. The student must show their face in the video for credit.
  2. The student must wear safety glasses covering their eyes to get credit.
  3. The student must submit a legible schematic. See the examples below for this lab schematic. Only one schematic is required for submission, but either or both are acceptable. The student can either show the industrial style or the electronic style, and they can show either with or without the latch.
    1.   AMAR-1200-Lab 12-2 - AC Par 3-4-3way switch with 240 and 120 Receptacles.PNG  
  4. The student must have their name, date, and lab number on the schematic.
  5. The wire colors must be on the schematic.
  6. All components must be labeled. This includes circuit breakers, push buttons, switches, motors, fans, solenoids, resistors, etc.
  7. The circuit must be wired to their schematic.
  8. The student measures the voltage at the receptacle. It should be around 12 to 15 volts.
  9. The student measures the voltage at the 240 V receptacle. They should show that they get around 12 to 15 V from the middle to one leg, 12 to 15 V from the middle pin to the other leg, and 24 to 30 V from leg 1 to leg 2.
  10. Any one of the three switches should turn the light on or off. If they are all up or all down, it will turn the light on or off respectively. Some students get this wrong, because they run the 4-way wires incorrectly. The brass screws from the first 3-way should go to the brass screws on the 4-way. The black screws on the 4-way should go to the brass screws on the second 3-way switch. The black screw of the first 3-way brings power in, and the black screw of the second 3-way runs power out to the light.
  11. The first 3-way brings power in on the black screw. The switch diverts power between the brass screws. There is always power leaving one of the brass screws. The brass screws of the first 3-way bring power into the 4-way. The 4-way switches between vertical connections to crossed connections. This means that one of the connections out will always send power to the second 3-way. The second 3-way brings power into one of the brass screws. When the switch connects such that one of the brass screws is connected to the black screw, it turns on the light. There are basically two lines in the circuit. One of the circuits will always have power on it and the other will not. By flipping any one of the three switches, the circuit switches between the two lines. If the line has power, the light turns on. If the line doesn't have power, then the light turns off.
  12. The student clearly shows lockout/tagout in their video.
  13. The student clearly shows that they have verified with a multimeter that the voltage is at or near 0V.

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