Growler
Growler
(OP)
I would like to make a growler (A/C electric magnet) out of a UPS transformer. I need to know if the orientation of the coil to the cut is important.
http://www.youtube.com/watch?v=yXQ0heuV6VE
http://www.youtube.com/watch?v=yXQ0heuV6VE





RE: Growler
you have to watch for over current protection
RE: Growler
RE: Growler
If you have to ask this there may be quite a few important things which you didn't know to ask.
Magnetic flux density and saturation come to mind. When you are cutting pieces out of the transformer core reflect; Would the designer have been willing to pay for the expense of the material which I am removing if he didn't have to? (Times a great number of units.)
A tip; run the transformer at half the rated voltage after you have raped the magnetic circuit. You may be able to reduce the saturation.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
1. could I use a variac to control the voltage
2. Is there any chance of changing the polarity of the device. I have heard people talking about changing positive ground devices like generators.
RE: Growler
Flash the generator when you instal it to ensure the correct polarity.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
1. This transformer has the secondaries wound around the primaries, should I apply the voltage to the primaries or the secondaries which are closer to the armateur.
2. Should I use a current limiter like a light bulb in series with the a/c line. I have seen some plans from the 1930's where they use a model T ignition coil with points as a current limiter, they put 32vdc on it and the points would open if there was a problem.
RE: Growler
connect a Variac to power the normal line voltage winding of the transformer. The first time, use a voltmeter and an ammeter in the circuit. At the applied voltage reaches the saturation point the current will increase alarmingly. Stay about 15% below this voltage. Model T coil?? I would think that this would be inapplicable to a growler but I have been wrong before. You may get an answer to this from someone who is very old.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
RE: Growler
Scroll down a bit on this article:
http://boo
RE: Growler
If there is not enough residual magnetism the generator will not build up voltage.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
RE: Growler
When I first read your post the attachment wasn't coming through. Now it is. Is that an actual cut or did you photoshop the second picture?
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
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If we learn from our mistakes I'm getting a great education!
RE: Growler
Second, scotty are you saying also cut the other leg of the transformer
Problem was its blowing the 10a fuse in the variac, I can only apply 20vac. Would the growler only work if an armature is in place or could a chunk of steel be a substitute?
RE: Growler
RE: Growler
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
RE: Growler
For an automotive generator a much lower voltage will be appropriate. You will have to do your own testing to find out.
Use a multi-meter, connect it to the brushes.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
RE: Growler
The windings in an armature typically take two or more paths between the brushes and are shorted to form a loop. The alternating magnetic field induces a voltage in both paths. If one path has a short or open, the currents will no longer be equal in both paths. The unequal currents will produce unequal magnetic field around both windings. These fields will no longer cancel and the armature under test will develop a magnetic pole on the surface of the armature. This may be detected with a hacksaw blade.
The voltages developed in both current paths will be equal. If there is a damaged coil this will cause a net difference in voltage to be developed at the brushes. This voltage will drop to zero when the damaged pole passes under the brush.
The growler is typically used for small automotive type armatures in generators that will probably be disassembled for cleaning and bearing replacement.
The AC test is typically used for larger DC motors, generators and exciters for trouble shooting. If a rotor is good, it need not be disassembled, and the rotor may well be too large for a growler in any event.
Bill
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"Why not the best?"
Jimmy Carter
RE: Growler
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