– Clip 1 Introduction to Back EMF charging, Part 1 – Clip 2 Testing procedures – Clip 3 Test Parameters – Clip 4 Test Equipment Part 1 – Clip 5 Bedini SSG circuit – Clip 6 Test Overview – Clip 7 Instrument Overview – Clip 8 Wheel, Rotor configuration – Clip 9 Solenoid Gap – Clip 10 Circuit Overview – Clip 11 Start-up of the Motor – Clip 12 Tuning the Motor – Clip 13 Connecting the charging Battery – Clip 14 Adding current Probe – Clip 15 Regulate the current flow – Clip 16 Increase the current – Clip 17 Add the Driving battery – Clip 18 Long time charging window – Clip 19 Switch off of power – Clip 20 Charge Graph – Clip 21 Calculation 1 – Clip 22 2N3055 Summary – Clip 23 End or Part 1

Clip 1

Clip 1

In the second series of the radiant energy project I will focus on the charging performance from the Back EMF. Our Benchmark is the 60 Watt charger and the time it take to recharge a battery to the voltage of 13.5 Volt. We consider the consumed power from the driving battery and the charging time of the drained battery. This ratio has to be better than 1.

Clip 2

Clip2

Back EMF charging Part 1

– Analyze the performance of the 2N3055 transistor
– Measure the charging rate and compare with the 60 Watt recharger
– Adding a two battery system for charging and driving and
compare to the Bench Top Power Supply
– Describe the performance impact of using neodymium magnets

Clip 3

Clip 3

Test Parameters

1. Voltage source 1 is a Bench Top Power Supply
2. Voltage source 2 are two batteries with 12 Volt and 8 AH
3. Bedini SSG circuit with 2N3055 transistor
4, 2 Bifilar solenoids to drive the wheel
5 Magnetic motor made of Nylon 6 with 3 kg or 6 pound rotor

Clip 4

Clip 4

Test Equipment Part 1

Tools

– Keithley 2110 Bench Digital Multimeter 5.5
– Agilent InfiniiVision 7000 Series oscilloscope MSO7014B
– Tenma handheld DMM
– UNI-T current clamp
– HP Laptop
– Bench Top Power Supply 20 Volt 5 A

Clip 5

Clip 5

Bedini SSG Cuircuit

All circuits will exact follow the schematics. The only change I made is to use a 500 Ohm
rheostat instead of a 1 Kohm and a 2 Watt 100 Ohm resistor to the base. Blue indicates the timing or trigger side and red the charging side. The current flow is regulated via the diodes.

Clip 6

Clip 6

In this episode of my series of Radiant Energy I will charge a battery via Back EMF from various transistors and MOSFET. The motor or the wheel will be the timing devise. We use here the Simplified School Girl circuit from Bedini. I build each circuit one to one to the schematic without modifications. The only modification is the resistance to the base of the transistor. I will use in addition a 50 Watt rheostat to regulate the current flow. We start with the 2N3055 transistor. The battery voltage will be brought down to 12 Volt as a starting point. We charge up the battery from 12 Volt to 13.5 Volt. All the measurements will be plotted in a chart from the Keithley 2110. We want to beat our reference charging time from the standard 60 Watt charger of around 39 minutes. I would prefer to recharge in less then 22 minuted because that was the time we drained the battery to 11 Volt from a 60 Watt load. All details will be provides as calculations on the blackboard.

Clip 7

Clip 7

I like to walk you through the setup of the charging test. We use the Keithley 2110 to measure the voltage and to plot it into the chart. We add then later on the Tenma handheld DMM to measure the voltage drop of the driving battery. At the moment we measure the voltage of the battery we want to charge. it shows 11.991 Volt. That is a good starting point. We use the bench top power supply to tune the system before we use the driving battery and measure the power consumption.

Clip 8

Clip 8

I like to give you now an overview of the configuration on my wheel. We have the solenoid on both sides connected in parallel. The black and red cable marks the primary winding and the white and green cable the trigger coil. The trigger coil go via a rheostat of 50 Watt and 500 Ohm. It leads to the base of the transistor via the on-board 100 Ohm 2 Watt resistor. We have here a neon bulb which will help to reduce the voltage between emitter and collector when a charging battery is not connected. This is important to protect the transistor. The transistor is only rated for 100 Volt and more voltage will damage it. The output is marked as black going to the coil and red going to the battery. The input on the right side goes to the bench top power supply to the negative polarity.

Clip 9

Clip 9

We have here the solenoid distance to the magnet of about 1 cm or about 1/2 Inch on both sides. The reason for that is that the magnets are far too strong for this configuration. In order to compensate you have to increase the distance between the stator and the rotor. When too close the power will not be enough from a 12 volt battery to repel the magnet and turn the wheel. The reach of the magnetic field is also too high. That means that sharp pulses are not possible the way we need it. The second problem is that the wheel is very heavy. In order to sustain the spinning of the wheel I have to maintain a certain level of current, otherwise the wheel will slow down and stop. This is about 350-400 mA. Bedini does not recommend to use these magnets and for a good reason. We later address that when I replace the neodymium magnets with ceramics. The ceramics are much weaker in a ratio 1 to 12. Pull power of the ceramics is a bout 1.5 KG to mild steel. The neodymium pulls with 12.5 KG. So we need to get much closer with the solenoids to the magnets of the wheel. Also the wheel has because of the weak magnets to be much lighter in weight. The repelling force is not that high of the ceramics. We will see how that performs in later videos. The movement of the wheel via the trigger coil has no other function than to time the pulse of the battery into the coil. Therefore to use anything else than a simple configuration is a waste.

Clip 10

Clip 10

 I give you now an overview of where I measure the reading for the oscilloscope. I read two values here. One coming to the resistor and diode, which is removing negative cycles on the base to achieve an exact timing. Here I read the voltage which comes from the trigger coil. This voltage is very high based on the strong magnets. You can say, this is a positive aspect because a very slow movement of the wheel will trigger the transistor. The transistor base does not need more than 1-2 volt. That is another reason Bedini did choose transistors (Audio). That is his background. The voltage of the trigger coil is very high and would require to use a zener diode to avoid destruction of the transistor. My couple of hours tests did so far not cause any issues with that. On the red cable, coming of the diode I measure the voltage of the Back EMF to the battery’s positive polarity. You will see the voltage level of that with neon shunt without the connection of the battery and afterward we connect the battery. Remember the ratio of voltage drop is a function of resistance, provided voltage and available current. If the current is low the voltage will drop to the ground. If it is high it will use the maximum voltage available and sustain it.

Clip 11

Clip 11

I will start the motor now. It speeds slowly up. You see on the below line many spikes. This is a feedback caused by the resistance to the base. This is also apparent on the Back EMF. The input voltage is indicate on the blue line. It is very high with over 110 volt. The top or yellow line is the left over voltage from the shunted neon. It is around 60 Volt.

Clip 12

Clip 12

You see here on the circuit that the neon is blinking with the frequency of the trigger coil or the wheel. I have to help the wheel to get it up to speed and adjust the voltage to the base. It increases in speed. We look at the oscilloscope and read 100 volt on the base and 41 Volt on the Back EMF side. I will now connect the battery.

Clip 13

Clip 13

I connect the battery and will slowly remove current from the base. When I connect the battery you see immediately a drop of current from the bench top power supply by 200 mA. The RPM of the wheel does not change much with slightly going up. We take readings every 5 seconds to the spreadsheet. I start to reduce now the voltage or current to the base. Monitor the bench top power supply closely. The maximum I can set the current to is 380 mA;  going lower and the wheel will slow down and stop. We have also to make sure that we are still charging the battery. I will measure the time until we reach 13.5 Volt on the battery.

Clip 14

Clip 14

I have added in the meantime a current probe on the oscilloscope. This allows me now to see the power the battery is charged with. We measure as amplitude not even one Watt. This measurement is a combination of the voltage to the current, maximum in a cycle. What is left of the Back EMF when connecting the battery is about 3.6 Volt. That is how much I can charge the battery with. Not enough to reach our goal. As you can see the charging rate is very slow.Frequency is 140 Hz. We take that as our value to calculate the RPM of the wheel.

Clip 16

Clip 16

I have decreased now the resistance to the base which increases the current from the power supply. The double spikes disappeared. The drop down voltage on the battery has increased to 5 Volt now but the charging frequency is not much higher. the base voltage has decreased to 38 Volt which is a much better value as safety margin. We have 1.3 – 1.5 Watt as an amplitude of power available. On the scope you see the alignment of current and voltage with the white line of power. Based on the charging frequency it will take us many hours to reach 13.5 Volt on the battery. The power requirement is 6 Watt at the moment. That is 1/10 of the power of the standard charger. It should take 10 times as long to charge. We had 39 minutes from the standard charger , so we look at 390 minutes for our configuration or 6.5 Hours.

Clip 17

Clip 17

I have connected both batteries now. One to charge and one to drive. What I can see immediately is that the voltage drop decreases to 10 volt from the Back EMF. Also the driving battery side does stop at some point discharging and slowly recharges. That happens only briefly. Power has because of that increased to 2.44 Watt. That is twice as much as we had before. Base voltage has now decreased further to 30 Volt. Frequency of the wheel has not changed

Clip 18

Clip 18

I have charged now the battery for some time with both batteries together in the circuit and take the measurement I have on the chart. The charging frequency is very slow. When I reach 12.319 Volt on the charging battery I will use this value as a reference base  for a 100mV window for my calculation.

Clip 19

Clip 19

I disconnect the driving battery now. What you see is the pure voltage caused by the magnets and wheel movement. We have 12.228 Volt on the driving battery and 12.320 on the charging battery. After disconnecting the battery you see the pulse from the magnets but less current. The power curve follows the voltage curve. The base voltage is good to see as well as over 20 volt and decreasing.

Clip 20

Clip 20

The time window
between 12.219 Volt and
12.319 Volt is selected
as linear charging
level for our calculation.

This calculation is only
theoretical because the
resistance increases with
Voltage and requires
more current to charge higher.

In this example it flats out at
12.320 Volt. No increase of
Voltage

Clip 21

Clip 21

We integrate our measurements into the formula

V = 12 Volt from the Bench Power Supply – V = 12.2 Volt from the driving battery
I = 0.4 A I = 0.7 A
P= V * I = 12 Volt * 0.4 A = 4.8 Watt P = 12.2 Volt * 0.7 A = 8.5 Watt
Voltage drop EMF to battery to 5 Volt Voltage drop to battery 10 Volt
RPM = HZ/8*60 = 140/8*60 = 1050 125/8*60 = 938
100 mV charge in 34.Minutes and 32 Seconds * 15 = 518 Minutes or 8.6 Hours
Power requirement = 8.5 Watt * 8.6 = 73.1 Watt

From 60 Watt battery charger, charged to 13.5 Volt in 39 Minutes and 12 Seconds
Power consumption is 39.12 Watt

Clip 22

Clip 22

2N3055 Charging Summary

– The 2N3055 drives well the wheel with low base voltage and current
– Voltage rating is low and switching speed is slow
– This has a negative impact on the Back EMF which does not exceed more than
100 Volt
– Current is very low on the EMF and does not exceed 2.5 Watt per spike.
– Neodymium Magnets are too strong and Solenoids don’t produce strong
spikes
– This combination is very inefficient
– Bedini uses 7 coils with 7 transistors to one charging battery via 2 trigger coils.

clip 23

Clip 23

End of Part 1
Back EMF charging