high voltage pulsed dc

[jazzyb]

Hi guys
By trade i am a electrical/mechanical engineer however my knowledge of electronics is on the beginner side so please bear with me.

I have built some custom made coils from some old motors and generators at my workplace of differing sizes and shapes and i'm experimenting in back emf, trying to work out which design works best with the ammount of energy put in. Iv'e come across some surprising results ! I'm sure you guys are well aware of two wires laid side by side increases capacitance right ?

This is my theory ... If i pulse a coil with say 1kv i will have a strong back emf it is my intention to capture this energy via a high v/diode and feed it back into the power supply .

This is not free energy, any one can tell you that, however if i use a 12 v battery to get the process started and have a circuit that say pulses a low milliamp but high voltage pulse square wave , it could in theory force the system to be very high effecient. This is my goal.

Like i said ive had some good results so far but i really need a circuit designing that runs at 60 hz fed with a 12v battery but pulsed on and off for the recapture of the back emf possibly into a cap or something similar and then that is reused into the power supply again.

Apologies for my lack of knowledge in your field guys.

 

[dknguyen]

Your system may be able to recover most of the energy draw from the battery but (if I understand you right) that is because the energy drawn from the battery does no work, and you are just drawing power from the battery and sticking it back in, experiencing losses along the way. So these losses, along with no other work being done, make a system with an efficiency of 0%.

Or are you just trying to draw power from the battery for nothing and sticking it back in the battery (minus the losses)? Because just connecting a battery to a capacitor will do that too and have less losses since the battery takes longer to actually empty (actually a battery just sitting there would be best).

Because energy used to perform work and those attributed to losses cannot be recovered and restored back to the system. THe only way you can recover most of the energy is if it was extracted from the source for no reason (ie. not used for work or anything really) and restored back into the source or stored somewhere else, minus losses.

THere are systems like motor drivers where the due to the way the motor is, energy is stored in it's winding inductance as it dissipates other energy input as work, and when you denergize the motor you can recapture this unused energy from the winding inductance to increase efficiency, but it's more of a side-effect and we have to make the most of it. Preferably the inductance would store no energy.

 

[jazzyb]

Hi mate thanks for replying.
I understand what you are saying however it is of my reasoning that electricity is only nuetralised at its source (battery) and is not consumed by any load ie heat, magnetism etc, these could be considered side effects of electron flow and do not consume it. Using high voltage instead of amps is alot easier to generate a magnetic field to induce into another coil for a load. also consider the back emf is stronger than forward.
What do you think ?

 

[mneary]

When your high back EMF is generated, it is at a much lower current and shorter duration than the source.

Voltage isn't energy. Energy is (voltage * current * time).

 

[Hero999]

Actually back EMF starts at exactly the same current as the source and decays to zero very quickly.

Take a perfect 1H inductor, connect it to a 1V battery for 1s and the current will build up to 1A. Now disconnect the inductor and the voltage across it will be infinite and will decay to zero in 0s.

In practice this will never happen as a spark will form. Suppose the spark gap in the switch breaks down at 1kV, when you disconnect your inductor 1A at 1kV will decay to 0A in 1ms.

 

[Nigel Goodwin]

I can't make any sense of what you're trying to do? - what EXACTLY is it?.

 

[jazzyb]

I have many different coils to experiment with and i'm trying to find out which will develop the greatest field strengh for induction while at the same time using as lttle power as it can.
I suppose i'm just fooling around at the end of the day. The reason i'm asking for a pulsed dc circuit at 60 hz is to try to find out how much of a load i can achieve, while capturing and re-using back emf.
Could anyone help me with a diagram ? As i said before i'm new with electronics.

 

[Hero999]

It sounds like you're trying to build a transformer; why don't you just buy one?

 

[Nigel Goodwin]

I have many different coils to experiment with and i'm trying to find out which will develop the greatest field strengh for induction while at the same time using as lttle power as it can.
I suppose i'm just fooling around at the end of the day. The reason i'm asking for a pulsed dc circuit at 60 hz is to try to find out how much of a load i can achieve, while capturing and re-using back emf.
Could anyone help me with a diagram ? As i said before i'm new with electronics.

You still make no sense?, why try and capture anything back?, just design it properly and supply what your load needs.