1. Look at the circuit in diagram 5.4 and use a board to wire it.
a. Remember to use BLACK wire for all connections prior to the load.
b. Remember to use WHITE wire for all connections from the load back to neutral.
c. You must have instructor check and sign off on the diagram before you plug it in.
2. Use the MARS type relay. The MARS relay looks like diagram 5.2 and has the contact and coil markings that you will see in diagram 5.3. The pins are numbered with #1 and #2 being normally closed and #1 and #3 being normally open. This is replicated with #4, #5, and #6 on the bottom. The two separated pins on the bottom of the relay is the relay coil. It doesn’t matter which side of the coil is the line or the neutral side.
Figure 20 – MARS relay (Courtesy MARS, Inc.)
Figure 21 – MARS relay wiring diagram (Courtesy MARS, Inc.)
Figure 22 – Line voltage relay wiring circuit
3. Once you have everything wired make sure you ask your instructor to check the circuit and initial it.
4. Now plug it in and sequence the switch. The lights should alternate between ON and OFF.
5. Use your meter and with SW2 open (off) check the following points of the circuit and record the voltages.
| POINT 1 | POINT 2 | VOLTAGE |
| 1 | 2 | |
| 1 | 3 | |
| 1 | 6 | |
| 1 | 4 | |
| 1 | 7 | |
| 1 | 8 | |
| 8 | 7 | |
| 1 | 9 | |
| 1 | 10 | |
| 9 | 10 | |
| 1 | 11 | |
| 10 | 11 | |
| 2 | 5 | |
| 2 | 7 | |
| 5 | 6 | |
| 7 | 8 |
6. Next, close SW1 (turn it on) and check your voltage reading again. Record them in the chart below.
| POINT 1 | POINT 2 | VOLTAGE |
| 1 | 2 | |
| 1 | 3 | |
| 1 | 6 | |
| 1 | 4 | |
| 1 | 7 | |
| 1 | 8 | |
| 8 | 7 | |
| 1 | 9 | |
| 1 | 10 | |
| 9 | 10 | |
| 1 | 11 | |
| 10 | 11 | |
| 2 | 5 | |
| 2 | 7 | |
| 5 | 6 | |
| 7 | 8 |
7. In your own words use the lines below to describe the sequence of operation.
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8. Make sure you understand the voltages across the loads, the open and closed switches and all the various points in the circuit. You will need this information for the rest of your career.
9. Before taking apart your circuits ask your instructor to check your work and initial your manual that you have completed this assignment. For those of you doing this in the classroom remember that sequence of operations is testable material.