Re: [TCML] Propeller style gap

[jhowson4@xxxxxxxxxxx]

you bring up a good point, I have a friend here at college who is very proficient in the machine shop. 

I am planning on using an aluminum rotor. The tungsten electrodes will be ring notched in 2 places with 4 modified screws on each notch, giving me the ability to actually lock them in place with a reasonable assurance. but I may change this a bit to further address safety issues. 

Thanks, 
John "Jay" Howson IV 

----- Original Message ----- 
From: "Brandon Garretson" <garretsontech@xxxxxxxxx> 
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> 
Sent: Sunday, November 28, 2010 1:39:54 PM 
Subject: Re: [TCML] Propeller style gap 

I have had great success using an 1800 RPM motor with a single flying 
electrode and four stationary electrodes to obtain a break rate of 120 
BPS. 
Doubling the RPMs in order to cut down on electrodes can make it more 
susceptible to balance and vibration issues if your craftsmanship is 
anything less than perfect. 
Lower RPMs can be a little more forgiving if you dont have access to 
precision tooling which may reduce the chance of a catastrophic 
failure. 


On Sun, Nov 28, 2010 at 10:52 AM, Futuret <futuret@xxxxxxx> wrote: 
> Hi John "Jay", 
> 
> Comments interspersed below: 
> 
> 
> -----Original Message----- 
> From: jhowson4 <jhowson4@xxxxxxxxxxx> 
> 
> Am I correct in that a 1800rpm propeller gap with 1 set of stationary electrodes 
> 
> 
> have a break rate of 60bps? thus meaning that a 3600rpm motor is a much better 
> 
> choice having a minimum of 120bps 
> 
> I fell pretty confident in the answer of yes, but figured I would check. 
> ---------- 
> Yes, correct, if your rotor has 2 spinning electrodes. Usually folks use 
> four spinning electrodes on the rotor to obtain 120 bps from an 1800 rpm 
> sync motor. For a propeller style gap to have 4 electrodes, a suitable hub 
> would need to be fabricated to hold the 4 spinning electrodes. 
> ---------- 
> 
> Besides the teletype motors, what other motors have you guys used for a 
> 
> propeller gap? 
> 
> My current design has a bit more metal on the rotor (I am adding thermal mass, 
> 
> and limiting the amount of tungsten needed) , so is there a motor that has a 
> 
> little higher hp, but also is already synchronous or can be easily modified to 
> 
> be as such? 
> ---------- 
> Any induction motor can be modified to make it synchronous by filing, machining, 
> or grinding flats onto the armature. This process can be considered either easy 
> or difficult depending on your mechanical skills and tools available. For a 
> 1725 rpm motor, 4 flats are needed. For a 3450 rpm motor, 2 flats are needed. 
> 
> 
> Cheers, 
> John 
> 
> 
> 
> Thanks, 
> 
> John "Jay" Howson IV 
> 
> 
> 
> 
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