Re: SRSG phase control? (and now also size of motor)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 4/2/01 4:16:02 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> 
>  >See:   http://hometown.aol-dot-com/futuret/page3.html
>  >
>  >Only a variac, capacitor, a fuse, and a resistor are needed.
>  >In some cases where a cap-run motor is used, only a variac is 
>  >needed.  
>  >
>  >John Freau
>  
>    Wow, this is great help!  Perhaps a naive question, but will the
>  "optimal" mechanical position of the sync gap change over time
>  (ignoring mechanical drift, etc.) or can a sync gap be set once
>  mechanically and forgotten?  

Kent,

If the Tesla coil remains unchanged, then the sync gap phase can
remain unchanged.  Thus it can be set mechanically as you
suggested and remain that way.

>  What if the gap is moved to a different
>  circuit (e.g. different neighborhood) or there the load on the current
>  circuit changes, perhaps as other inductive loads are changed?

the neigborhood and other inductive loads in the building probably
won't make much difference.  The gap phase position can remain fixed.
>  
>    It was not completely clear how the capacitor is chosen however.
>  Do you just try various caps and compare the voltage difference across
>  the motor?

Yes, i should clarify that at the webpage.  It is indeed a trial and
error process as you suggest.
>  
>    Also, I noticed that you are using 1/20 HP motor for your gap, but
>  other people recommend more like 1/4HP.  Is this difference because
>  yours is a true sync motor and the minimal suggestion of 1/4HP is for a
>  motor modified for salient pole operation?  I guess I am looking for 
>  some reassurance that a 1/6HP is fine or if I should go ahead and
>  use a spare 1/4 or 1/3HP.

I used a 1/50HP sync motor for my TT-42 TC.  It is true that you
will lose power when you modify a motor, but much depends on
the weight of the rotor disc.  If the rotor is very heavy, it's possible
that even 1/4HP will not be enough.  Much will also depend on
whether the motor is cap start, cap run, or induction start.

John Freau

>  
>    Thanks.
>  
>  ---
>  Kent Vander Velden