Single- and Three-Phase Power Measurements

Electromechanics Laboratory
Electrical Engineering 208
Experiment 1
Single- and Three-Phase Power Measurements
Cooperative Engineering Program
Springfield, MO
Laboratory Work
Begin by connecting the Lab Volt console to the three-phase power source. Then turn on the
console and connect it to the laboratory computer.
Single-Phase Measurement
Once all of this is up and running connect the top terminal of the three-phase variable AC output
to the E1 terminal of the data interface module and then go from the output of the data interface
through the I1 current terminal of the data interface and on into the top terminal of the resistance
module and over to the top terminal of the inductor module. Then complete the circuit by wiring
back through bottom of the inductor and resistor module back to E2 on the data interface module
and down to terminal 6 of three phase source.
Set the panel meter to measure the voltage between 5 and 6, and after having the instructor check
your wiring turn the source on and slowly increase the voltage until current starts to flow through
the series RL single-phase load. Read the voltage, current, watt, var, and apparent power values
off of the lab computer. Do not exceed the current rating of the resistor or inductor. Record the
measured values and the oscilloscope plots.
Three-Phase Measurement
Now connect the second and third terminals of the three-phase power source in a manner similar
to the way the first source was connected. Connect this though the data interface and into the
resistor and inductor modules. Energize the completed circuit and slowly increase the current.
Do not exceed the rated current of the inductors or resistors. Measure the three-phase voltages,
currents, and powers. Observe the waveforms on the oscilloscope and print them out.