Amplidyne - a mechanical amplifier

[Neo-X]

Hellow 2 all.. I read this unique generator a long time ago and theres something that bothers me. This amplidyne is used as amplifier like a transistor rather than a generator. The large output power from the rotor is controlled by the weak power from the stator. The rotor has 2 set of brushes at right angle. One is shorted and the other one is connected to the output. The wierd thing here is the shorted coil on the rotor generate strong magnetic field even if the stator magnetic field is very weak and this strong magnetic field is cut by the winding at right angle which generate lager output voltage and current. If theres a way to make it solidstate it could possibly get overunity.

[Goat]

Hellow 2 all.. I read this unique generator a long time ago and theres something that bothers me. This amplidyne is used as amplifier like a transistor rather than a generator. The large output power from the rotor is controlled by the weak power from the stator. The rotor has 2 set of brushes at right angle. One is shorted and the other one is connected to the output. The wierd thing here is the shorted coil on the rotor generate strong magnetic field even if the stator magnetic field is very weak and this strong magnetic field is cut by the winding at right angle which generate lager output voltage and current. If theres a way to make it solidstate it could possibly get overunity.

Hello Neo-X 

Thanks for bringing this generator to my/our attention!

I looked at your post and it made me think, how is it that they claim a "power gain" in these devices?

Here's some references:

An amplidyne is an electromechanical amplifier: http://en.wikipedia.org/wiki/Amplidyne

In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output. : http://en.wikipedia.org/wiki/Gain

An amplifier is a device for increasing the power of a signal by use of an external energy source. : http://en.wikipedia.org/wiki/Amplifier

When they mention "power gain" are they talking OU or amplifying a signal at the expense of an input, I noticed they mention "increase the power from the input to the output" which to me suggests OU, does it not?

In any event, I'm curious as to how easy or complicated it would be to re-wire a 4 pole DC motor with a control winding on it.

For other info see the following from : http://roughrecord.blogspot.ca/2010/11/amplidyne.html

"Amplidynes are special-purpose dc generators. They supply large dc currents, precisely controlled, to the large dc motors used to drive heavy physical loads, such as gun turrets and missile launchers.         [/size]
The amplidyne is really a motor and a generator. It consists of a constant-speed ac motor (the prime mover) mechanically coupled to a dc generator, which is wired to function as a high-gain amplifier (an amplifier is a device in which a small input voltage can control a large current source). 

For instance, in a normal dc generator, a small dc voltage applied to the field windings is able to control the output of the generator. In a typical generator, a change in voltage from 0-volt dc to 3-volts dc applied to the field winding may cause the generator output to vary from 0-volt dc to 300-volts dc. If the 3 volts applied to the field winding is considered an input, and the 300 volts taken from the brushes is an output, there is a gain of 100. Gain is expressed as the ratio of output to input:         

(http://www.tpub.com/neets/book5/0033.GIF)

In this case 300 V ÷ 3 V = 100. This means that the 3 volts output is 100 times larger than the input.  The following paragraphs explain how gain is achieved in a typical dc generator and how the modifications making the generator an amplidyne increase the gain to as high as 10,000. The schematic diagram in figure 1-22 shows a separately excited dc generator. Because of the 10-volt controlling voltage, 10 amperes of current will flow through the 1-ohm field winding. This draws 100 watts of input power (P = IE).         

(http://www.tpub.com/neets/book5/32NE0416.GIF)

Assume that the characteristics of this generator enable it to produce approximately 87 amperes of armature current at 115 volts at the output terminals. This represents an output power of approximately 10,000 watts (P = IE). You can see that the power gain of this generator is 100. In effect, 100 watts controls 10,000 watts.   An amplidyne is a special type of dc generator. The following changes, for explanation purposes, will convert the typical dc generator above into an amplidyne.

Figure 1-23. - Brushes shorted in a dc generator.

(http://www.tpub.com/neets/book5/32NE0417.GIF)   

The first step is to short the brushes together, as shown in figure 1-23. This removes nearly all of the resistance in the armature circuit. Because of the very low resistance in the armature circuit, a much lower control-field flux produces full-load armature current (full-load current in the armature is still about 87 amperes). The smaller control field now requires a control voltage of only 1 volt and an input power of 1 watt (1 volt across 1 ohm causes 1 ampere of current, which produces 1 watt of input power).The next step is to add another set of brushes. These now become the output brushes of the amplidyne. They are placed against the commutator in a position perpendicular to the original brushes, as shown in figure 1-24. 

The previously shorted brushes are now called the "quadrature" brushes. This is because they are in quadrature (perpendicular) to the output brushes. The output brushes are in line with the armature flux. Therefore, they pick off the voltage induced in the armature windings at this point. The voltage at the output will be the same as in the original generator, 115 volts in our example.

Figure 1-24. - Amplidyne load brushes. 

(http://www.tpub.com/neets/book5/32NE0418.GIF)

As you have seen, the original generator produced a 10,000-watt output with a 100-watt input. The amplidyne produces the same 10,000-watt output with only a 1-watt input. This represents a gain of 10,000. The gain of the original generator has been greatly increased.As previously stated, an amplidyne is used to provide large dc currents. The primary use of an amplidyne is in the positioning of heavy loads through the use of synchro/servo systems. Synchro/servo systems will be studied in a later module.

Assume that a very large turning force is required to rotate a heavy object, such as an antenna, to a very precise position. A low-power, relatively weak voltage representing the amount of antenna rotation required can be used to control the field winding of an amplidyne.

Because of the amplidyne's ability to amplify, its output can be used to drive a powerful motor, which turns the heavy object (antenna). When the source of the input voltage senses the correct movement of the object, it drops the voltage to zero. The field is no longer strong enough to allow an output voltage to be developed, so the motor ceases to drive the object (antenna). The above is an oversimplification and is not meant to describe a functioning system. The intent is to show a typical sequence of events between the demand for movement and the movement itself. It is meant to strengthen the idea that with the amplidyne, something large and heavy can be controlled very precisely by something very small, almost insignificant."
I would appreciate any comments as I'm unclear about the power gain in these devices, is it a usable idea?

Edit:  Added pics from links.  Sorry for the format of the quote.

Regards,
Paul

[Neo-X]

@goat
Thanks for posting this information. It will help others to understand how it works. I have an idea now of how can we make it solidstate. Instead of rotating the rotor to induce voltage in its coil, we can use ac in stator coil to induce voltage in the rotor similar in induction motor. Using phase shift we make a rotating magnetic field in stator so no need to rotate the rotor. We can use the standard induction motor in this setup. Because the rotor coil of induction motor is shorted, it will make a huge current and magnetic field. I imagine what if we add a additional coil to the rotor so that the shorted coil magnetic field will induce voltage in the additional coil similar to the amplidyne? Would it make a huge power gain in the additional coil?

[neptune]

There seems to be a lot of confusion about what an amplifier is, and what it does. As an example take an audio amplifier, used with a microphone. If we connected a microphone directly to a loudspeaker, we would get little or no sound from the speaker, because the output energy from the microphone is tiny, a few microwatts. So we amplify this signal. That means, we make a more powerful COPY of it. So the loud sound that we now get from the speaker is powered by mains electricity. Yes, all of the actual power used to move the speaker cone comes from the mains, with the microphone signal controlling it . So the device described above works just like a transistor, albeit a very powerful one. No overunity here.

[Neo-X]

You doesnt get my point.