help-rapid cap bank charging

Mag Man · May 9, 2016

I am currently using forced air cooling at transformers. What about graphene
capacitor?

Mag Man · May 9, 2016

What about graphene capacitor?

kubeek · May 9, 2016

How does the type of capactior in anyway influence that your transformers are overheating?

Mag Man said:
I was considering dc/ac converter circuitry such as used for automobile cigarette
lighters, ie; 10-20amp 12vdc input = 120vac 33amp output(4000watt),adapting this
technology to achieve 500vdc(bridges) 30+amps. No market for such a thing therefore nothing manufactured

How many times do we have to explain that converting 12V@20A to 120V@33A is not possible, therefore that device you are talking about could never have existed?

AnalogKid · May 9, 2016

Mag Man said:
No market for such a thing therefore nothing manufactured

No.

There is no such device. It does not exist. It cannot exist.

And yes, there is a market for it. If you have a device that takes 120-240 W at its input and produces 4000 W at its output with no other energy source connected, you will be worth $1,000,000,000 tomorrow.

ak

Mag Man · May 9, 2016

kubeek said:
How does the type of capactior in anyway influence that your transformers are overheating?
How many times do we have to explain that converting 12V@20A to 120V@33A is not possible, therefore that device you are talking about could never have existed?

Saturday, May 7, 2016

AnalogKid said:
No.

There is no such device. It does not exist. It cannot exist.

And yes, there is a market for it. If you have a device that takes 120-240 W at its input and produces 4000 W at its output with no other energy source connected, you will be worth $1,000,000,000 tomorrow.

ak

Mag Man · May 9, 2016

Mag Man said:
Saturday, May 7, 2016

dcacpowerinverters.com model en4000

kubeek · May 9, 2016

Nowhere does it say that it is powered from 12V 20A, it has large aligator clips and thick cables to connect straight to a battery. Even then I doubt that it is capable of delivering 4kW and not burning to a crisp.

Nigel Goodwin · May 9, 2016

Mag Man said:
I was considering dc/ac converter circuitry such as used for automobile cigarette
lighters, ie; 10-20amp 12vdc input = 120vac 33amp output(4000watt),adapting this
technology to achieve 500vdc(bridges) 30+amps. No market for such a thing therefore nothing manufactured

You need to do the simple maths, you're suggesting the impossible - there's no such thing because it's impossible.

However, I'm presuming you're probably chasing some impossible 'over unity' scheme and aren't bothered by real world physics.

tcmtech · May 9, 2016

Mag Man said:
dcacpowerinverters.com model en4000

That model draws 375 amps at 4000 watts output and ~750 amps at its 8000 watt surge capacity rating.

spec · May 9, 2016

Mag Man said:
I was considering dc/ac converter circuitry such as used for automobile cigarette
lighters, ie; 10-20amp 12vdc input = 120vac 33amp output(4000watt),adapting this
technology to achieve 500vdc(bridges) 30+amps. No market for such a thing therefore nothing manufactured

Hy Magic Man,

You may not believe this, but it is a fundamental law of physics that the energy out of a system cannot exceed the energy into a system. Any one who claims otherwise is mistaken. You can work out the input power by multiplying the input voltage by the input current to give input watts. The output watts can never exceed the input watts, that is output current multiplied by output volts.

Can you explain the purpose of your circuit. You seem to be generating a high magnetic field, but what for?

Is there any scope for changing the capacitors and the windings on the coil.

Also, would it be OK if the circuit was was non isolated. Ie did not use transformers.

Do you have a 120V 0 120V balanced mains supply

I take it that your mains frequency is 60Hz

spec

Mag Man · May 9, 2016

spec said:
Hy Magic Man,

You may not believe this, but it is a fundamental law of physics that the energy out of a system cannot exceed the energy into a system. Any one who claims otherwise is mistaken. You can work out the input power by multiplying the input voltage by the input current to give input watts. The output watts can never exceed the input watts, that is output current multiplied by output volts.

Can you explain the purpose of your circuit. You seem to be generating a high magnetic field, but what for?

Is there any scope for changing the capacitors and the windings on the coil.

Also, would it be OK if the circuit was was non isolated. Ie did not use transformers.

Do you have a 120V 0 120V balanced mains supply

I take that your mains frequency is 60Hz

spec

Mag Man · May 9, 2016

The goal is to produce 5000-10000 gauss in a focused field (ie,iron core) over a
10-20 mS time at a repetition rate of 60-70mS, so I am open to ideas on efficiency
and design, otherwise the project must remain classified at this time. For the moment I am using standard house power 120vac 60hz on a 30amp circuit. this is
only proof of concept stage. thanks

spec · May 9, 2016

AnalogKid said:
Don't think so. You could have significant current circulating among the mismatched transformer secondaries, current that further increases transformer heating while diverting energy away from the load. The bridge diodes act as droop-share resistors. Co-locating them on a common heatsink will improve load balancing.

ak

The secondary coils will be made from copper which has a positive temperature coefficient; this encourages temperature sharing. Diode VF has a relatively high negative temperature coefficient. I am not sure about the diode bulk resistance. But the VF varies from diode to diode as does the bulk resistance so I do not agree that individual bridges would improve current sharing, quite the reverse. The other point is that the single bridge approach is simpler by five bridges. Also for a given conductivity a single bridge would be cheaper. The higher the conductivity the faster the capacitors will charge. It is all a mater of degree though.

spec

spec · May 9, 2016

Mag Man said:
The goal is to produce 5000-10000 gauss in a focused field (ie,iron core) over a
10-20 mS time at a repetition rate of 60-70mS, so I am open to ideas on efficiency
and design, otherwise the project must remain classified at this time. For the moment I am using standard house power 120vac 60hz on a 30amp circuit. this is
only proof of concept stage. thanks

Thanks Magic,

That clarifies things a bit- we do not need to know your application.

I will give your requirements some thought and if all goes well I will post a schematic for consideration quite soon

spec

ronsimpson · May 9, 2016

I can't see timing but I think that when the IGBT is on, there is a point where the capacitors are down to 50 volts.
So you have the power line shorted to 50 volts. (for a time) This must be stressful on the transformers.

AnalogKid · May 9, 2016

Mag Man said:
I am currently using forced air cooling at transformers. What about graphene capacitor?

That will not improve cooling.

ak

tcmtech · May 9, 2016

Okay?

So what size are your step-up transformers in Volt-Amperes?

What sort of iron ar you using for your core that can handle 5000 - 10,000 gauss without going into saturation?

How are you protecting your IGBT and your capacitor bank from the massive inductive kickback and resulting voltage and current spikes of the collapsing magnetic field of your coil?

schmitt trigger · May 9, 2016

Mag Man said:
The goal is to produce 5000-10000 gauss in a focused field

As TCMTECH has mentioned, magnetic materials, to which iron and steel belong to, have a saturation flux density. Once that you reach saturation, no matter how much electromotive force you apply, you will not get additional flux density. At least not on the steel's surface area.

Good magnetic steels saturate around 16,000 Gauss.

Mag Man · May 9, 2016

spec said:
Thanks Magic,

That clarifies things a bit- we do not need to know your application.

I will give your requirements some thought and if all goes well I will post a schematic for consideration quite soon

spec

Mag Man · May 9, 2016

Thanks spec- appreciated

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