Re: [TCML] How To Turn A Vacuum Cleaner Motor Into A Synchronous Motor

[Futuret <futuret@xxxxxxx>]

 I did another experiment.  I removed the diode and installed a 9 ohm, 1 watt
resistor in its place.  The resistor connects the 2 opposed areas of 3 shorted
segments.  I didn't try using 4 shorted segments on each side of the 
commutator.

The motor runs quite well this way.  It self starts, and
runs synchonously between 25V and 34V.  If the voltage is raised too high
causing the motor to lose sync-lock, then to obtain sync-lock again, the
voltage has to be decreased to 25V.  

If the motor voltage is switched on (instead of being gradually raised using
the variac knob), then the motor will sync-lock between 25V and 29V.
The current draw varies from 3.5A to 4.0A depending on the input voltage.

There is no arcing at the brushes.  Apparently the use of a diode causes the 
brush arcing.  

The only problem with this resistor method is that the resistor gets too
hot.  I can try connecting two 19 ohm, 2 watt resistors in parallel (one
on each side of the commutator).  I can also try using more resistance.
Maybe the motor can still self-start using about 16 ohms or more. 

Cheers,
John

 


 

 

-----Original Message-----
From: Futuret <futuret@xxxxxxx>
To: tesla <tesla@xxxxxxxxxx>
Sent: Wed, Dec 29, 2010 11:55 am
Subject: Re: [TCML] How To Turn A Vacuum Cleaner Motor Into A Synchronous Motor 


Another idea is to use only a resistor (no diode).  The resistor should be 
selected to pass only enough current to permit self-starting.  
By not using a diode, there would be more room for the resistor. 
 A resistor can be placed on each side of course to allow for 
the use of smaller resistors, for better heat radiation, and for 
balance. By using resistors only, the motor should give good 
sync-locking, self-starting, and no arcing at the brushes.

Cheers,

John



 





 



 



-----Original Message-----

From: Teslalabor <teslalabor@xxxxxxxxxxx>

To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>

Sent: Wed, Dec 29, 2010 9:05 am

Subject: Re: [TCML] How To Turn A Vacuum Cleaner Motor Into A Synchronous Motor



Hi,





I just did some experiments. I removed the brushes completely and only 



connected the stator coils. I realized, that this is just impossible, 



because of the only 2 stator coils and the lack of a capacitor, no rotating 



magnetic field is generated and this never could work. I tried everything, 



also the adition of 2 more shorted segments (4 on each side) with diodes 90 



degrees appart, diodes in opposite diections, but without the brushes in 



place, the rotor doesn't rotate anymore. It only creates some forces and 



locks in different positions.



Stefan







 

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