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I was trying to make a generator out of a DC motor inrunner by following this video by following this schematic: 1 enter image description here

I made this structure and started testing the phase voltages. A-, B+, C- are combined together and made as the neutral wire. enter image description here

While testing the voltage outputs from A_neutral, B_neutral, C_neutral, V_ab, V_bc and V_ac, I am getting non-uniform outputs and I am getting problems troubleshooting this issue.

Voltage_cb

Voltage_cb

Voltage_ab

Voltage_ab

Voltage_ac

Voltage_ac

Voltage_a_with_neutral

Voltage_a_with_neutral

Voltage_b_with_neutral

Voltage_b_with_neutral

Voltage_c_with_neutral (almost no voltage, dont know why)

Voltage_c_with_neutral (almost no voltage, dont know why)

Why is the voltage_cneutral almost nil compared to the other voltages? I checked the copper coil winding and they are all same.

shadesofpurplegreen
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  • Most of us won't watch a video link. (1) Add a schematic using the button on the editor toolbar. (2) Explain what "inrunner" means. (I never heard of it.) (3) Explain the change in voltage on the a-N trace. – Transistor Aug 03 '16 at 07:14
  • Thanks, I have updated. Although I am not ale to explain the change in the voltage on the a-N trace, I was moving around the wires for adjustment which caused a big surge. I still have not understood. – shadesofpurplegreen Aug 03 '16 at 07:20
  • You don't have a neutral, you don't need a neutral. Where did your neutral come from??? Maybe your neutral is the problem?? You only need to rectify the 3 phases with 6 diodes, no neutral in sight. Look up '3 phase full wave recitifier'. – Neil_UK Aug 03 '16 at 07:23
  • (1) You still haven't explained "inrunner". (2) There is no neutral on those wiring diagrams. – Transistor Aug 03 '16 at 07:24
  • @Neil_UK A-, B+ and C- are soldered together and made as neutral – shadesofpurplegreen Aug 03 '16 at 07:33
  • @Neil_UK A+, B- and C+ are the three phase inputs. – shadesofpurplegreen Aug 03 '16 at 07:39
  • @Transistor Inrunner is a type of brushless motor that is used in radio controlled models – shadesofpurplegreen Aug 03 '16 at 07:40
  • "inrunner" implies "BLDC" which implies it generates 3-phase AC. The OP needs a 3-phase bridge rectifier (6 diodes) to get his DC output. At a wild guess, unless he's wired it Y not Delta, there is no neutral (I'm not going to attempt to read his scribble, he also needs to draw a proper schematic) –  Aug 03 '16 at 10:38
  • @BrianDrummond Yes this is a Y configuration – shadesofpurplegreen Aug 03 '16 at 11:05

1 Answers1

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It seems like you have a loose connection somewhere. With magnet wire, you need to carefully scrape the varnish off the surface of the wires, twist them together and solder them. The voltage A to neutral trace shows the voltage jumping up and down. That must be the result of a loose connection. The scope patterns seem to be inconsistent with one another. It appears that moving the scope probes may move the wires so that the connections change.

  • I found the problem, it was giving inconsistent output because of main line interference similar to [this](http://electronics.stackexchange.com/questions/78920/my-scope-detects-a-50hz-signal-when-the-probe-is-not-connected-to-a-circuit-is). – shadesofpurplegreen Aug 04 '16 at 10:25