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Author Topic: Measuring Amps on output coils  (Read 14071 times)

Offline nathanj99

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Measuring Amps on output coils
« on: March 16, 2015, 11:16:33 PM »
Hi

I have built a wheel with 16 magnets around it much like the bedini SG. I put a coil on the bottom with no other electronic components just to see if I could get anything from the coil. I have connected my mulitimeter to the coil. When i spin the wheel by hand I may get about 10 milliamps but it is not constant. However when i spin the wheel fast I get no reading at all! Only when the wheel is moving slowly can i get about 30 miliamps. Can someone explain what I am doing wrong. Once the wheel just about stops turning the wheel will start to speed up again. I guess this is the energy in the coil doing this?

I am on a very steep learning curve, so would appreciate any advice.

thanks

Nath

Free Energy | searching for free energy and discussing free energy

Measuring Amps on output coils
« on: March 16, 2015, 11:16:33 PM »

Offline FatBird

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Re: Measuring Amps on output coils
« Reply #1 on: March 16, 2015, 11:22:11 PM »
How many turns on the coil, & what gauge wire are you using?

Can you post a picture of it?
                                                                                                                .

Offline mscoffman

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Re: Measuring Amps on output coils
« Reply #2 on: March 16, 2015, 11:36:30 PM »
Maybe, coil wires and magnetic flux lines are not cutting each other. Show diagram.

Offline burnit0017

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Re: Measuring Amps on output coils
« Reply #3 on: March 16, 2015, 11:44:01 PM »
Hi, what is the wire size and number of turns on the coil?

Offline gyulasun

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Re: Measuring Amps on output coils
« Reply #4 on: March 17, 2015, 12:25:19 AM »
Hi Nath,

Perhaps your digital multimeter is not able to show the higher than 50 or 60 Hz AC current? just guessing and you could check this by using a full wave diode bridge to rectify the AC voltage and use your meter in DC volt range across the diode bridge output where you also attach some hundred microFarad puffer capacitor for some filtering too?
If this sounds double dutch to you just search the web for full wave rectifier circuit with a puffer capacitor and you will be ok.

Gyula

Free Energy | searching for free energy and discussing free energy

Re: Measuring Amps on output coils
« Reply #4 on: March 17, 2015, 12:25:19 AM »
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Offline nathanj99

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Re: Measuring Amps on output coils
« Reply #5 on: March 17, 2015, 11:13:46 AM »
Thanks everyone.

I will post details of my build later. Had to go to flipping work! I had another attempt this morning and I did start getting some readings. Although the numbers were jumping all over the place! I guess I need a analogue amp meter? I do seem to get higher amps (10mAmps) when the wheel is slow. If I speed it up I get around 1 mAmp. But it could just be down to the meter. Would the collapsing emf mess up the value shown on the dmm? Is there a better way to measure the amps? I had a look at capacitors but as yet have no idea what size I need.

Nath

Offline MarkE

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Re: Measuring Amps on output coils
« Reply #6 on: March 17, 2015, 11:24:48 AM »
You should get one positive and one negative pulse from each passing magnet.  If your coil does not have a load, then you've got a basic generator and the peak voltage across the coil is determined by the number of turns, the strength of the magnets, the gap and the speed of the wheel.  If you pulse current from a battery or a power supply through the coil, and you don't do something to clamp the coil, or the signal through the meter, then you will get a big BEMF spike each time you interrupt the current.

Generally speaking, you will have an easier time if you use a shunt resistor for the current measurement.  Then you can insert any kind of needed filtering and/or protection between the current sense resistor and the DMM input.  It will also let you keep the wiring loops as small and tight in the circuit itself, which is important for pulse circuits.

Free Energy | searching for free energy and discussing free energy

Re: Measuring Amps on output coils
« Reply #6 on: March 17, 2015, 11:24:48 AM »
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Offline sm0ky2

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Re: Measuring Amps on output coils
« Reply #7 on: March 17, 2015, 12:15:18 PM »
Thanks everyone.

I will post details of my build later. Had to go to flipping work! I had another attempt this morning and I did start getting some readings. Although the numbers were jumping all over the place! I guess I need a analogue amp meter? I do seem to get higher amps (10mAmps) when the wheel is slow. If I speed it up I get around 1 mAmp. But it could just be down to the meter. Would the collapsing emf mess up the value shown on the dmm? Is there a better way to measure the amps? I had a look at capacitors but as yet have no idea what size I need.

Nath

Hi Nathan,

When you generate electricity in this manner, alternating north and south poles, the current will come out as an A/C wave-form.
+ then -, respectively.
So you will need an A/C meter or a scope to get any kind of accurate reading.
some quick-response DC meters may show the result, but it flashes back and forth so its hard to see the read out.

another option may be to run the coil leads through a square-wave or full-wave rectifier
then you have a DC current to measure. This will be minus the losses through the diodes, of course.
which can also be measured with your DC meter then add the values up

hope this helps

Offline nathanj99

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Re: Measuring Amps on output coils
« Reply #8 on: March 18, 2015, 09:36:50 AM »
You should get one positive and one negative pulse from each passing magnet.  If your coil does not have a load, then you've got a basic generator and the peak voltage across the coil is determined by the number of turns, the strength of the magnets, the gap and the speed of the wheel.  If you pulse current from a battery or a power supply through the coil, and you don't do something to clamp the coil, or the signal through the meter, then you will get a big BEMF spike each time you interrupt the current.

Generally speaking, you will have an easier time if you use a shunt resistor for the current measurement.  Then you can insert any kind of needed filtering and/or protection between the current sense resistor and the DMM input.  It will also let you keep the wiring loops as small and tight in the circuit itself, which is important for pulse circuits.

Could you explain to me why i get one positive and one negative pulse from each magnet please. What sort of shunt resister should i use?

So what i have at the moment it a 90cm wheel with 16 magnets around it. I was experimenting with a coil sat underneath the wheel. The distance between coil and magnets is about 3-5mm. I was messing about with a coil of 1.00mm wire, 2.2 ohms, 1066 turns. I have a coil of bifilar which i have not yet put the core in. That is 0.45mm 1619 turns.

Nath

Offline MarkE

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Re: Measuring Amps on output coils
« Reply #9 on: March 18, 2015, 12:51:27 PM »
Could you explain to me why i get one positive and one negative pulse from each magnet please.
Because as the magnet approaches the coil, the flux will increase quickly in one direction, reach a maximum rate of change, and then the rate of change will fall to zero very close to where the magnet makes its closest approach.  That makes a voltage pulse in one direction.  As the magnet moves from its closest approach the reverse process occurs and a complementary shaped voltage pulse forms in both time and amplitude.
Quote

 What sort of shunt resister should i use?
Use a resistor that has a low inductive impedance compared to the resistance at the signal frequencies you are measuring.  Your basic frequency with 16 magnets will be:  rpm*0.267.  I don't know how sharp your rise times will be, so let's just take a gross stab and say that they are  about 1/350th the magnet to magnet interval.  So, the signal frequency content will be significant up to around RPM*0.267*350/0.35 ~= rpm*270.  I am going to venture that you are staying under 2000rpm, so I expect the frequency content will be mostly under 500kHz.  You would like jwL @ 500kHz < 0.1*RCSR.  So, a tabulation:

L < 0.314uH*R

R = 100 Ohms, L < 31uH, 5W resistor safely handles 170mA rms
R = 10 Ohms, L < 3.1uH, 5W resistor safely handles 0.5A rms
R = 1 Ohm, L < 310nH, 5W resistor safely handles 1.7A rms
R = 0.1 Ohm, L < 31nH, 5W resistor safely handles 5A rms

These resistors from Digikey have practical inductances down around 3nH, and they are affordable, handle a decent amount of power, and are 1%:  http://www.digikey.com/product-search/en?pv1=1323&pv1=1025&pv1=1028&pv1=103&pv1=2358&FV=fff40001%2Cfff80482%2C1c0002&k=wne&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25.

You should solder sense wires to each side of the resistor, right at the body.  You can tightly twist those wires together and take them away to your oscilloscope probe, or DMM.
Quote

So what i have at the moment it a 90cm wheel with 16 magnets around it. I was experimenting with a coil sat underneath the wheel. The distance between coil and magnets is about 3-5mm. I was messing about with a coil of 1.00mm wire, 2.2 ohms, 1066 turns. I have a coil of bifilar which i have not yet put the core in. That is 0.45mm 1619 turns.

Nath

Free Energy | searching for free energy and discussing free energy

Re: Measuring Amps on output coils
« Reply #9 on: March 18, 2015, 12:51:27 PM »
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Offline Low-Q

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Re: Measuring Amps on output coils
« Reply #10 on: March 18, 2015, 07:09:11 PM »
Hi

I have built a wheel with 16 magnets around it much like the bedini SG. I put a coil on the bottom with no other electronic components just to see if I could get anything from the coil. I have connected my mulitimeter to the coil. When i spin the wheel by hand I may get about 10 milliamps but it is not constant. However when i spin the wheel fast I get no reading at all! Only when the wheel is moving slowly can i get about 30 miliamps. Can someone explain what I am doing wrong. Once the wheel just about stops turning the wheel will start to speed up again. I guess this is the energy in the coil doing this?

I am on a very steep learning curve, so would appreciate any advice.

thanks

Nath
First advice: Provide all neccesary information.
Example of neccessary information:


Coil details -> Number of turns, coil hight/outer-inner diameter, wire gauge, inner resistance of the coil, iron core/air core
Distance between coil and magnets
Angular velocity of the magnets
Magnets orientation, assambly details.
Magnetic flux crossing through the coil measured in Gauss
Voltage readings over the coil.
Load details - whatever you use, bulb, resistor, short circuit. Provide resistance values.


An unloaded coil will not cause any current flow at all. You must load it. Also, you get AC out of the coil. Not DC. Check your instrument what setting you've choosen.


What's most interesting here, is the voltage x ampére product. I mean Watt or Joule pr./second - applies only on pure resistive loads. Ampére alone does not carry energy. Voltage alone does not carry energy.


Vidar


Offline nathanj99

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Re: Measuring Amps on output coils
« Reply #11 on: March 18, 2015, 10:32:04 PM »
Because as the magnet approaches the coil, the flux will increase quickly in one direction, reach a maximum rate of change, and then the rate of change will fall to zero very close to where the magnet makes its closest approach.  That makes a voltage pulse in one direction.  As the magnet moves from its closest approach the reverse process occurs and a complementary shaped voltage pulse forms in both time and amplitude.Use a resistor that has a low inductive impedance compared to the resistance at the signal frequencies you are measuring.  Your basic frequency with 16 magnets will be:  rpm*0.267.  I don't know how sharp your rise times will be, so let's just take a gross stab and say that they are  about 1/350th the magnet to magnet interval.  So, the signal frequency content will be significant up to around RPM*0.267*350/0.35 ~= rpm*270.  I am going to venture that you are staying under 2000rpm, so I expect the frequency content will be mostly under 500kHz.  You would like jwL @ 500kHz < 0.1*RCSR.  So, a tabulation:

L < 0.314uH*R

R = 100 Ohms, L < 31uH, 5W resistor safely handles 170mA rms
R = 10 Ohms, L < 3.1uH, 5W resistor safely handles 0.5A rms
R = 1 Ohm, L < 310nH, 5W resistor safely handles 1.7A rms
R = 0.1 Ohm, L < 31nH, 5W resistor safely handles 5A rms

These resistors from Digikey have practical inductances down around 3nH, and they are affordable, handle a decent amount of power, and are 1%:  http://www.digikey.com/product-search/en?pv1=1323&pv1=1025&pv1=1028&pv1=103&pv1=2358&FV=fff40001%2Cfff80482%2C1c0002&k=wne&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25.

You should solder sense wires to each side of the resistor, right at the body.  You can tightly twist those wires together and take them away to your oscilloscope probe, or DMM.

Wow thanks Mark. But seriously, that went way over my head. Maybe i should just quit at the woodwork stage :( . I just cannot get your equations and calculations. I dont really have much hope at this do i?

Nath

Offline sm0ky2

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Re: Measuring Amps on output coils
« Reply #12 on: March 18, 2015, 10:56:59 PM »
Ampére alone does not carry energy.
Vidar

Could you provide an example of where Ampere exists, without voltage?

Offline Low-Q

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Re: Measuring Amps on output coils
« Reply #13 on: March 22, 2015, 10:33:13 AM »
Could you provide an example of where Ampere exists, without voltage?
In superconductors. Current flow has nothing to do with voltage.
In the oposite case, you can have voltage, but no current (Ampéres).
Normal conductors have loss due to resistance. This resistance will cause a voltage drop when current flows through it.
Therfor you might assume that you cannot have a current flow without applying voltage.


For example: You only need current to make a magnetic field.
Permanent magnets have this current going on on an atomic level, but there is not voltage involved.
Also the reason why permanent magnets cannot provide free energy, because the product of current and voltage is zero.


Vidar





Offline tinman

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Re: Measuring Amps on output coils
« Reply #14 on: March 22, 2015, 12:12:09 PM »
In superconductors. Current flow has nothing to do with voltage.
In the oposite case, you can have voltage, but no current (Ampéres).
Normal conductors have loss due to resistance. This resistance will cause a voltage drop when current flows through it.
Therfor you might assume that you cannot have a current flow without applying voltage.


For example: You only need current to make a magnetic field.
Permanent magnets have this current going on on an atomic level, but there is not voltage involved.
Also the reason why permanent magnets cannot provide free energy, because the product of current and voltage is zero.


Vidar
Current flow has everything to do with voltage. If you have no potential difference,then current will not flow. The voltage differential may be very small,but there has to be one. I must also ask how current flows in ferrite magnet's,as the ferrite is non conductive,and even if it were,you would have nothing but a dead short. A dead short with current flowing through it means extensive heat-->PMs do not get hot sitting on the bench.

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Re: Measuring Amps on output coils
« Reply #14 on: March 22, 2015, 12:12:09 PM »

 

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