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Re: ARSG Motors (fwd)



---------- Forwarded message ----------
Date: Mon, 27 Aug 2007 17:45:56 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: ARSG Motors (fwd)

Hi Jeff,

No, the possibility still exist. As the rotary speed is 
increased/descreased, the charge rate is varied accordingly and is not 
in sync with the charge rate. It's simply the ability to change speeds 
and bps for a given cap/transformer configuration. So, the same 
situation applies to DC motors as well. It's no different in that respect.

Take care,
Bart


 
Tesla list wrote:

>---------- Forwarded message ----------
>Date: Mon, 27 Aug 2007 11:27:02 -0400
>From: Jeff Fink <revtec@xxxxxxx>
>To: 'Tesla list' <tesla@xxxxxxxxxx>
>Subject: RE: ARSG Motors (fwd)
>
>If one builds a dc arsg, doesn't the possibility of overvolting the NST
>disappear?
>
>Jeff
>
>-----Original Message-----
>From: Tesla list [mailto:tesla@xxxxxxxxxx] 
>Sent: Monday, August 27, 2007 9:42 AM
>To: tesla@xxxxxxxxxx
>Subject: Re: ARSG Motors (fwd)
>
>
>---------- Forwarded message ----------
>Date: Sun, 26 Aug 2007 10:28:36 -0700
>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: ARSG Motors (fwd)
>
>Hi Phil,
>
>The cap is charged at a specific rate (60Hz). ALthough the ARSG has a 
>specific rpm, will not be synchronous with the cap charge timing (and 
>this is what counts). This causes the voltage required to arc the gap to 
>constantly vary. The timing of the arc fires at points all along the 
>60Hz line, through zero crossing, etc.. The charge cycle is constantly 
>varied with the charging frequency. In the end, the result is a varying 
>voltage. NST's are quite sensitive to overvolting, so it's easy to see 
>why ARSG's are not recommended. Pigs and PT's seem to handle the 
>variation fine.
>
>SRSG's are recommended for NST's as it simply helps maintain a constant 
>voltage at the time of arc (and even that's not perfect). LTR certainly 
>is recommended for such operation.
>
>I think when it comes to performance, it's really difficult to compare 
>the two (apples and oranges). Of course, variable speed gaps (such as a 
>VFD or DC motor) adds an adjustment capability to bps. But, just like 
>the ARSG, the varying voltage is an issue to keep aware of if one is 
>thinking on running an NST with it.
>
>Take care,
>Bart
>
>Tesla list wrote:
>
>  
>
>>---------- Forwarded message ----------
>>Date: Sun, 26 Aug 2007 11:17:50 EDT
>>From: FIFTYGUY@xxxxxxx
>>To: tesla@xxxxxxxxxx
>>Subject: Re: ARSG Motors (fwd)
>>
>>While we're on the subject, here's something I thought of the other  day:
>>
>>   If you run an ARSG, by definition it's asynchronous  to the power line 
>>frequency. However, when you run it at exact multiples or  fractions of the
>>    
>>
>line 
>  
>
>>frequency, it *is* synchronous at that setting. 
>>   However, the phasing relative to the line frequency  will be variable, 
>>depending on circumstances preceding the synchronous setting. 
>>   In other words, for a 60 Hz line frequency: If  you run the motor at
>>    
>>
>1801 
>  
>
>>rpm, then drop it to a synchronous 1800 rpm, the  phasing will depend on
>>    
>>
>the 
>  
>
>>physical rotor position at the instant the rotor  spins at 1800 rpm. If you
>>    
>>
>
>  
>
>>come off that synchronous setting, and then return,  the phasing will
>>    
>>
>probably 
>  
>
>>be different every single time.
>>   So for those of you who run ARSG's, my question is  this:
>>   If we make such a big deal out of phasing for  SRSG's, then obviously 
>>phasing at (at least) the synchronous speeds is  important. Have you guys
>>    
>>
>noticed 
>  
>
>>a performance change when sweeping through the  synchronous speeds, or when
>>    
>>
>
>  
>
>>setting to a synchronous speed, depending on the  arbitrary phase
>>    
>>
>relationship? 
>  
>
>>Do you sometimes have to come off synchronous a  tad, then return to it to 
>>"hunt" for a particular "sweet spot" in the phase  relationship?  
>>   Does anybody run a "phase control" or do phase  adjustments with an
>>    
>>
>ARSG? 
>  
>
>>Does it make a performance difference? 
>>   Or does running an ARSG just give you "beats" of  good performance, and
>>    
>>
>
>  
>
>>it takes a bit of fiddling to obtain and maintain a "good"  setting?
>>
>>   I'm following Bart's lead by putting together a  3-ph VFD setup for my 
>>RSG. I already had a 3/4 hp single-phase motor I modified  for a SRSG, but
>>    
>>
>so 
>  
>
>>many folks advocate the ARSG for pig setups that I figured  I'd give it a
>>    
>>
>try. I 
>  
>
>>think another important advantage is the control over  the motor's accel to
>>    
>>
>
>  
>
>>speed, so as not to mechanically shock the rotor system  when starting up.
>>
>>   Thanks!
>>
>>
>>-Phil LaBudde
>>Center for the Advanced Study of Ballistic  Improbabilities
>>
>>
>>
>>************************************** Get a sneak peek of the all-new AOL
>>    
>>
>at 
>  
>
>>http://discover.aol.com/memed/aolcom30tour
>>
>>
>>
>>
>>
>> 
>>
>>    
>>
>
>
>
>
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