Dave,
I am not sure if you can have some zero crossing to sync to single phase
peaks but I had very good results with a blown spark gap and dual 15/60's,
see Richard Quick Blown Gap in the older archives. Easy to make. I used an
electric leaf blower with a long plastic round nozzle, also see the sucker
gaps. I think you would need a single phase motor running synchronous to
keep firing at the peaks and keep it simple.
Did anyone suggest etching off the copper pads on your board? Where you
soldered would be unaffected. It may be best just to redo it though.
Jim Mora
-----Original Message-----
From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Dave Boyle
Sent: Wednesday, September 17, 2014 6:38 PM
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] Resin or fiberglass perfboard for terry filter?
The motor is a 3 phase 208v 1/2 horse driven by a vfd. Does it make
sense to grind flats on it's armature?
On 09/17/2014 08:50 PM, David Speck wrote:
> Dave,
>
> "Pretty close" is not good enough. When your gap drifts far enough
> away from optimum synchronization, the NST will fail permanently.
>
> Look at the old posts that describe how to file flats on a motor
> armature to convert it to a fully synchronous motor. Then, you can
> use a Freau phase adjuster to precisely set the phase angle of the
> motor without having to mechanically rotate the motor body.
>
> (Another) Dave
>
> On 9/17/2014 7:12 PM, Dave Boyle wrote:
>> Oh now you tell me! Hey what about if I operate my spark gap motor in
>> the synchronous zone? At 1 or 2 beats per cycle with the nst switched
>> off while the motor changes speeds? I have an led strobe synced to
>> the ac line light that I use to see when the disc is at the right
>> position. I can't get a phase lock but I can keep it pretty close.
>> Maybe I should build a custom inverter that will run the motor at
>> only those speeds that are safe.
>
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