Re: [TCML] SRSG with John Freau Phase Control

[SusaX2 X2 <susax2@xxxxxxxxx>]

Hi,

well, actually there are 3 wires coming out of the motor. the original run
cap is connected between 2 of them. I'll send you the schematic off-list.
Mark

2012/8/3 Quarkster <quarkster@xxxxxxx>

> Mark -
>
> Glad to hear that your phase controller is working well.
>
> However, I did have a question about your synch motor. Regarding the motor
> windings, you mentioned the ratio of 3 resistances "between the three
> wires....".  In your Wikipedia link to the semi-star winding diagram, it
> appears that there are only two windings that you can access through the
> motor leads (W1 to U1, and W1 to V1). Please clarify how you measured the
> three different resistance values.
>
> Quarkster
>
> --- On Thu, 8/2/12, SusaX2 X2 <susax2@xxxxxxxxx> wrote:
>
>
> From: SusaX2 X2 <susax2@xxxxxxxxx>
> Subject: [TCML] SRSG with John Freau Phase Control
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Date: Thursday, August 2, 2012, 3:09 PM
>
>
> Hi Guys,
>
> today I finished my new SRSG with John Freau's Phase Controller.
> Here's a youtube video of the assembly in action
> > http://www.youtube.com/watch?v=83ZdeQyoCqQ <
>
> Since I don't have a scope I found an easy way to check if
> the motor runs in sync and also the adjustable phase angle.
>
> I took a strobe light used for checking ignition timing and
> connected a small and simple mechanical relay (from tv or microwave PCB)
> to where the signal clamp used to be.
> The relay is connected via single rectifier diode to a small transformer
> powered from mains.
> This way the strobe flashes 50 times a second, mains frequency ofcourse.
> (The tricky part was getting the camera's shutter time right..)
>
> The motor is a 2HP 3000rpm 50Hz 220V single phase induction motor
> with 2 flats milled on the rotor for salient pole operation.
> The motor has it's original 30uF run capacitor and
> it is internally wired semi star, since resistance between the 3 wires has
> a 3:2:1 ratio
> > http://nl.wikipedia.org/wiki/Bestand:Steinmetzschema-3.svg <
>
> The phase controller has a 5A variac and a 18uF run capacitor
> with a 1.5MOhm bleeder resistor. (And a 10A fuse ofcourse
> to protect the variac in case the brown stuff hits the fan)
>
> It has almost 90 degrees phase control over 70% of the variac's range
> before loosing sync. I didn't measure any voltage rise at all,
> voltage starts dropping as soon as the variac is turned.
>
> I reckon almost 90 degrees is a maximum for a 3000rpm motor
> and almost 45 degrees max. for a 1800 rpm motor.
> This should make sense if you consider the 2 (or 4) field windings
> and the position of the milled flats;
> If you push the rotor to the point where the 2 flats meet up
> with the point where the 2 field windings separate,
> it's fighting 2 opposite magnetic fields.
>
> Many kudos to John for inventing the phase controller.
> I will though, accept all credits for the method
> to check if the thing's working or not ;)
>
> Mark
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