Your Turn Sampling and Displaying the Three Phase Voltage Outputs

If you look at the code under the label Exp_5_Retrieve_For_Piotting, you'll notice that only one of the four read statements are not "patched out", and only the read of phase 1 is active. We will build up to the entire four-channel plot on an additive basis by taking out the comments (■) from each read statement one-at-a-time. If we showed you the entire four-channel plot at this time, you would become very confused (as we were when we first saw it). So we'll lead up to the four-channel display slowly beginning with just phase 1.

V Anchor your wind turbine and arrange your table fan so that the turbine blades are turning steadily and briskly.

V Run the program AlternatorPhase1.bs2.

V Close the Debug Terminal after noting which COM port it is using.

V Open StampPlot Pro by clicking on Start ^ Programs ^ Parallax Inc ^ StampPlot ^ Experiments with Renewable Energy ^ sic_ewre_exp_45.spm.

V Set the COM port in StampPlot to the same one that was being used by the Debug Terminal.

V Click on the Connect button, and make sure the Enable Plotting box is checked. Figure 6-12 shows what you should be seeing on your computer, a plot of only phase 1.

!" Ei>«r|gy f xpfiBiwnh 4 md '■ ■ I Li-"" 1'h v.- ' In' ¡4 h? l'it VI " 11 ■■■- ■ :-In- iTw-ii ■■ hrvi I nullum " - ' j^j rt ri»™i [i^i Pli AiH v^i :Ho

!" Ei>«r|gy f xpfiBiwnh 4 md '■ ■ I Li-"" 1'h v.- ' In' ¡4 h? l'it VI " 11 ■■■- ■ :-In- iTw-ii ■■ hrvi I nullum " - ' j^j rt ri»™i [i^i Pli AiH v^i :Ho

Figure 6-12: Stamp Plot Plot of Phase 1

Figure 6-12: Stamp Plot Plot of Phase 1

By comparison, Figure 6-13 shows what one full cycle of phase 1 looks like as displayed on an oscilloscope. Notice how the entire waveform is shown. You don't see the negative-going portion on StampPlot since our program only samples above zero volts.

Puillm U5B IIKIIBm^ ■ DIpUl RMlflitiirÔÎKÏÏGÏMpî-^[-

Puillm U5B IIKIIBm^ ■ DIpUl RMlflitiirÔÎKÏÏGÏMpî-^[-

Figure 6-13: Oscillos cope Plot of Phase 1

To display both phase 1 and phase 2 together you will need to uncomment the read instructions for phase 2. (Or, you can download AlternatorPhase1-2.bs2.)

V Disable StampPlot by clicking on the Disconnect button, then bring up the BASIC Stamp Editor.

V In the Exp_5 Retrieve_For_Piotting subroutine, delete the apostrophe in front of the second read command:

Exp_5_Retrieve_For_Plotting:

'READ (eepromAddr - $30 + plotCount), ch3 READ (eepromAddr - $2 0 + plotCount), ch2 READ (eepromAddr - $10 + plotCount), ch1 'READ (eepromAddr - $00 + plotCount), ch0

V Re-run the program.

V Now close the Debug Terminal and bring up the StampPlot screen back up.

V Re-enable it by clicking on the Connect button, at the same time making sure that the Enable Plotting box is also checked.

You should see something like that shown in Figure 6-14.

Figure 6-14: StampPlot Plot of Phase 1 and Phase 2

Once again, by comparison Figure 6-15 shows what one cycle of each phase looks like as displayed on an oscilloscope.

Stampplot Pro Pic
Figure 6-15: StampPlot Plot of Phase 1 and Phase 2

To display phase 1 and phase 3 together you will need to uncomment the read instructions for phase 3, and comment out phase 2 again. (Or, you can download AlternatorPhase 1-3.bs2.)

V Disable StampPlot by clicking on the Disconnect button, then bring up the BASIC Stamp Editor.

V In the Exp_5_Retrieve_For_Piotting subroutine, replace the apostrophe in front of the second read command, and delete it from the first one:

Exp_5_Retrieve_For_Plotting:

READ (eepromAddr - $3 0 + plotCount), ch3 'READ (eepromAddr - $20 + plotCount), ch2 READ (eepromAddr - $10 + plotCount), ch1 'READ (eepromAddr - $00 + plotCount), ch0

V Re-run the program.

V Now close the Debug Terminal and bring up the StampPlot screen back up.

V Re-enable it by clicking on the Connect button, at the same time making sure that the Enable Plotting box is also checked.

You should see something like that shown in Figure 6-16.

Figure 6-16: StampPlot Plot of Phase 1 and Phase 3

Note the tiny dip on the positive part of the wave for Phase 3. This is the "signature" of our particular three-phase AC alternator. Yours will certainly be different due to the particular way your (hand-wound) coils were arranged in the stator and the way your magnets were (hand) placed on the rotor.

Phase 3 not dropping below 0.5 volts? If your plot of Phase 3 doesn't drop down below 0.5 or 0.25 volts, try making your turbine turn faster. This was experienced by our testing staff (;-) and a faster turbine gave the better-looking plot shown above.

Figure 6-23 shows what one cycle of each phase looks like as displayed on an oscilloscope.

Figure 6-17: Oscilloscope Plot of Phase 1 and Phase 3

Before displaying all three phases and the rectified output, let's first look at phase 1 and the rectified output by themselves. You will need to uncomment the last read instruction, and comment out phase 3 again. (Or, you can download AlternatorPhase1-R.bs2.)

V Disconnect in StampPlot, then bring up the BASIC Stamp Editor.

V In the Exp_5_Retrieve_For_Plotting subroutine, place the apostrophe in front of the first and second read commands, and uncomment the third and fourth as shown:

Exp_5_Retrieve_For_Plotting:

'READ (eepromAddr - $30 + plotCount), ch3 'READ (eepromAddr - $20 + plotCount), ch2 READ (eepromAddr - $10 + plotCount), ch1 READ (eepromAddr - $0 0 + plotCount), ch0

V Re-run the program, and close the Debug Terminal.

V Bring up StampPlot again.

V Click on Connect, making sure that the Enable Plotting box is also checked.

Figure 6-18: StampPlot Plot of Phase 1 and Rectified Output

You should see something like that shown in Figure 6-18. Now compare this to the oscilloscope plot of the same thing in Figure 6-19.

Puillm U5B OlÎHBÎÎfi ■ DlçUnl RMlflitiirÔÎKÏÏGÏMpî-^[-

Puillm U5B OlÎHBÎÎfi ■ DlçUnl RMlflitiirÔÎKÏÏGÏMpî-^[-

Figure 6-19: Oscilloscope Plot of Phase 1 and Rectified Output
Figure 6-20: Oscilloscope Plot of Phase 1 and Rectified Output (different time scale) Now for the grand finale - displaying all three phases and the rectified output in one plot.

V Disable StampPlot by clicking on the Disconnect button, then bring up the BASIC Stamp Editor.

V In the Exp_5_Retrieve_For_Piotting subroutine, delete all apostrophes in front of the read commands, so they will all be executed. (Or, download AlternatorPhase 1 -2-3-R.bs2.)

Exp_5_Retrieve_For_Plotting:

READ (eepromAddr - $10 + plotCount), ch1

V Re-run the program.

V Now close the Debug Terminal and bring up the StampPlot screen back up.

V Re-enable it by clicking on the Connect button, at the same time making sure that the Enable Plotting box is also checked.

You should see something like that shown in Figure 6-18.

*" iMIfr CiftllfeMrik A ud H ■ Phrw I'Iwit ■■■«m+'^l P»ÏJ" IWI Ulisd fariin Will Ibiai H - ' $ ^

*" iMIfr CiftllfeMrik A ud H ■ Phrw I'Iwit ■■■«m+'^l P»ÏJ" IWI Ulisd fariin Will Ibiai H - ' $ ^

Stampplot Channel

Figure 6-21: StampPlot Plot of All Three Phases and Rectified Output

Figure 6-21: StampPlot Plot of All Three Phases and Rectified Output

Since we don't have a 4-channel oscilloscope we can't show you a comparable display. However, we hope you now understand why we lead up to the four-channel display by taking you there one step at a time. You can see the confusion that would have resulted if we would not have done so.

In terms of comparing the StampPlot plots with the oscilloscope plots, you may have noticed that the bottom, zero voltage, part of the waveforms is shown on the oscilloscope plots. The reason you don't see the negative-going portion on StampPlot is because our program only samples above zero volts. Nevertheless, the StampPlot plots are still quite representative of the actual waveforms.

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

Get My Free Ebook


Post a comment