Phase shift Lissajous on old Eico 427 Oscilloscope

Discussion in 'General Electronics Chat' started by adamprince2, Apr 30, 2015.

  1. adamprince2

    Thread Starter New Member

    Apr 30, 2015
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    I built a phase converter to convert single phase 240v 60hz (2 hot wire and ground) to three phase 240v 60 hz (3 hot wires L1, L2, L3 and a ground).

    I want to the check the phase shift using the Lissajous method on my old Eico 427 Scope (similar to Eico 460). There is no XY mode.

    I'm using unshielded banana leads with alligator clips. There are 5 jacks on the machine. Say I want to check the phase shift between L1 and L3 for example.

    What are the proper jacks to attach the leads to?

    How many leads do I use?

    What spot should the sync selector and the sweep selector be?

    The manual is here: http://bama.edebris.com/manuals/eico/460/
    Pg. 7 of the pdf file describes the measurement somewhat.

    I have attach a photo of the face of the scope. The knob at the top right is intensity.
    The rings around the knobs also turn to for further adjustments.
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Your scope does have X-Y mode. The right hand set of inputs can be selected as the X deflection, while the left hand set drives the Y in the conventional way...
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    Set the SWEEP SELECTOR to EXT HOR.

    SYNC SELECTOR should have no effect.
     
  4. adamprince2

    Thread Starter New Member

    Apr 30, 2015
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    So one lead into the left Vert input and one into sync G? So just two leads are needed?
     
  5. MikeML

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    Three:
    Scope ground (also likely connected to Green wire in the line cord) is the common between the two voltages. Be damn careful. You could wind up with 100s of V on the scope case...
     
  6. BR-549

    Well-Known Member

    Sep 22, 2013
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    Show us the converter print.
     
  7. adamprince2

    Thread Starter New Member

    Apr 30, 2015
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    Ok, so 1 lead to Left Vert input, 1 lead to sync G (I think that's ground), and one to right Horz. input. I have attached the converter print.
     
  8. MikeML

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    Add to this diagram where you propose to connect the scope (all three connections).
     
  9. BillB3857

    Senior Member

    Feb 28, 2009
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    Page 7 of the manual you linked explains it very well, even showing examples.
     
  10. adamprince2

    Thread Starter New Member

    Apr 30, 2015
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    I redrew the diagram with the scope (pic 1). I hooked it up as drawn. When the sweep selector was on Ext. Hor. I did not get anything but fuzz. So I put the sweep selector on Sin 60 and got this image (pic2). I can change the shape by moving the ring around the Horz. Gain -pos (pic 3). I can even make it a vertical line. Did I hook the scope up correctly? Which image do I read to get the phase angle between L1 and L3?

    This is my 1st time using an oscilloscope. I read pg. 7 before posting, but I need the step by step junior picture book version.
    :) static converter steveco.jpg IMG_20150501_181905.jpg IMG_20150501_181400.jpg
     
  11. BillB3857

    Senior Member

    Feb 28, 2009
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    Your diagram has me totally confused. You are showing the pressure switch to be shorting out the starter coil when closed? Also, by setting the SYNC SELECTOR to 60Hz, you are using a sample of the 60Hz power supply of the oscilloscope as the drive for the horizontal sweep. Inside the box you drew representing the contactor, does the N of the incoming line tie to anything other than the scope? Does the motor run?
     
  12. adamprince2

    Thread Starter New Member

    Apr 30, 2015
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    -I made a mistake in the drawing of the pressure switch. It should not be shorting out the start coil. I corrected the drawing.
    -The ground (N?) is connected to the sheet metal of magnetic contactor. It also should be grounded in the circuit breaker box.
    -Yes, the motor starts and seems to run fine at 180 uF. I have a whole table on voltages/amps at different capacitor uF. I don't notice the motor slow down with higher pressures, but I have not measured it's rpm. I want to check how close the phase shift is to 120 degrees to fine tune things.

    -So Sync Selector should be on Ext. And the Sweep selector should be on what? Thank you for your time.
     
  13. BillB3857

    Senior Member

    Feb 28, 2009
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    Sweep selector doesn't matter when using an external sweep source.
     
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