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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

----- Original Message ----- From: "Futuret" <futuret@xxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, December 18, 2010 5:37 PM
Subject: Re: [TCML] How To Turn A Vacuum Cleaner Motor Into A Synchronous Motor


Hi Stefan,

Nice tests, thanks. The motor seemed to show about 105 degrees of phase shift using the phase shifter and to me it sounded sweet :) It would be nice to measure the voltage across the motor while varying the phase shifter knob, to see if there
happens to be any resonant voltage rise at some position, and how much.
I realize you just used the existing capacitor value. Using voltage control, the amount of phase shift seemed a little less, but still seemed good. It's good to
see that the phase controller works well with universal motors also.

Yes, I see the motor is powerful. Apparently your motor is much stronger than
a vacuum cleaner motor.

I see two general questions:

1) I wonder if there's a way to determine the optimal number of segments to short
   for a given motor?

2) I wonder if the diodes help for self starting (compared to the method I tried)?

I just realized that since my motor has fewer segments than yours, by shorting
4 segments, I actually shorted more segments as a proportion of the total.

Cheers,
John










-----Original Message-----
From: Teslalabor <teslalabor@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sat, Dec 18, 2010 10:40 am
Subject: Re: [TCML] How To Turn A Vacuum Cleaner Motor Into A Synchronous Motor


Hi,



I performed 2 tests, the phase shifter and the modified motor under load

conditions.



First the phase shifter - as expected it works well:



http://www.youtube.com/watch?v=PRi1x2SOUFI



Of course I didn't check for optimal capacitance value, I just took my

shifter which normaly runs one of my SRSG's. At the end of the video I'm

shifting the phase by adjusting the input voltage, but I think with the

shifter the results are better.



Then I did a test under load conditions - not

with a disk attached to the motor but I simulated a heavy load by driving

another washing machinemotor (unmodified) via a belt drive which runs in

generator-mode and powers 2 500W halogen bulbs. Here the testvideo:



http://www.youtube.com/watch?v=MP7EUGSDIpE



The motor on the left is an unmodified washing (universal-) motor with 800W.

I apply a DC voltage of 8V to it's stator coils for generating the stator

field. When driven by the right (modified, 4 segments at each side)) motor,

the generator delivers 100Volts into 2 halogenbulbs, each 230V/500W

connected in parallel. As you can see they glow nearly at half brightness,

so there are arround 500W electrical energy + some mechanical friction the

modified motor has to deal with.

When abruptly braking the modified motor by turning the statorfield of the

generator on and off, you can see there is no big phase change. But in SRSG

operation this is not of concern because there are no abrupt brakings.

Also watch the beld how it is deformed by the forces ;)

Believe me, these motors can drive EVERY G10 disk with heavy tungsten rods

;-)



Stefan




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