[TCML] LTR/STR and spark length

[bartb]

Yes, but a dimmer for a fan speed control is fine (if desired).
I would personally use a mechanical means unless electronic control was 
either required or cheaper (work ethic mostly).

Bart

G Hunter wrote:
> Lamp dimmers have some limited uses in coiling.  I
> have found that cheap, 120vac/600W lamp dimmers sold
> at Wal-Mart and similar outlets make dandy speed
> controls for vacuum cleaner motors (used on sucker
> gaps).  I have also used dimmers as speed controls for
> asynchronous rotary spark gaps based on universal-type
> brush motors.  One ARSG was based on an angle grinder.
>  Another was based on a small Black & Decker router. 
> Dimmers controlled these with no issues.  Lastly, a
> dimmer and a series motor run capacitor work well for
> exciting a 12v car ignition coil from a 120vac outlet.
>  I've tried this with various caps and ignition coils,
> and it has always worked with no damage to the dimmer.
>
> Not all motors will tolerate a dimmer.  Most AC
> induction motors--even the cheap little shaded pole
> motors--will seize up when placed in series with a
> dimmer.  I've never ruined a motor or a dimmer this
> way--the motors simply refused to rotate and made
> scary buzzing sounds.
>
> On the other hand, most brush-type "universal" motors
> used in vacuum cleaners and many common power tools
> respond very smoothly to dimmer speed control.
>
> My cheesy, homebrew secondary coil winding jig uses a
> gear motor from an ice cream maker (low RPM, lotsa
> torque, great for coil winding).  Unfortunately, the
> little shaded pole induction motor inside the thing
> balks at dimmer speed control--won't budge.  With a
> 10A variac in series, the thing can be smoothly
> throttled across its whole RPM range.  Sometimes, you
> just gotta bite the bullet and shell out for a variac.
>
> Cheers,
>
> Greg
>
> --- neal at imagesbyneal.com wrote:
>
>   
>> Hi Scott,
>> You think a dimmer wouldn't work properly even on a
>> cooling fan? I do have a
>> smaller (5 amp)variac that I could use, but like
>> previously suggested, I may
>> not adjust the flow at all. If I had to, I could go
>> the baffle route. I've
>> heard this before about dimmer switches. What is the
>> problem with them, in
>> relation to coils? Thanks for your help,
>>
>> Neal.
>>
>>
>>
>> Quoting Scott Bogard <teslas-intern at hotmail.com>:
>>
>>     
>>> Neal,
>>>      Never use a dimmer with anything coil
>>>       
>> related, it will not work
>>     
>>> properly.  Many of us have been down this road, it
>>>       
>> never ends well.
>>     
>>> Either buy a variac, or in this circumstance I
>>>       
>> would suggest that you
>>     
>>> just build a baffle like Bart said.  It can be as
>>>       
>> simple as a piece of
>>     
>>> cardboard taped to the back or your fan covering
>>>       
>> it partly.  Best of luck!
>>     
>>> Scott Bogard.
>>>       
>>
>>     
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