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Discussion Starter #1
A picture says a million words -
in this case it rendered me speechless -

As I had written before, I`m waiting now close to 6 month to receive parts to get my ep junior controller repaired.

I received another mail from Mr. Paul Zigouras, stating the parts are on the way, and an installation guide to assemble the now new and impoved genuine Zigouras engineering circuit.

I did ask about the purpose of the fuses on the gate, the answer was:

"They`ll protect the electronics"
Don`t any body say, there`s no protection circuitry in epc industrial controllers!

Could it be EPC`s New Year Joke? Can someone ask please?:)

Btw, sofar I did`t receive any parts nor a tracing number.
 

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Discussion Starter #3
Slowly I begin to doubt Mr. Zigouras knowledge about powerelectronics.

As overshooting voltages resulting in spikes and ringing are known hurdles with hard switching pwm, adjusting rise and fall times offer a remedy to this.

How come, it`s not used in epc`s industrial controllers?

Clamping the gate is not just a good idea. How come it`s not found on epc controllers?

Paul, those are questions about understanding power electronics:

Could a long gatewire in combination with a fuse increase di/dt and why do designers try to minimize especially this parasitic element?

A high di/dt with a gate charge, forms …. what?

Why is it, that a designer can not simply add max volt and amp values when rating their controller, what would you suspect to be the reason for this, Mr. Zigouras?

How do you determine the maximum voltage and the maximum current your industrial controllers should be exposed to, without roasting them?
(Hint) The ep jr did work fine dimming a light bulb at 60V in my lab.

Mr. Zigouras, here you have the unique chance to show us your superior engineering knowledge by answering to those very reasonable questons, of a customer -
 

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Slowly I begin to doubt Mr. Zigouras knowledge about powerelectronics.
Slowly you begin to doubt?!? We've been doubting his knowledge of anything besides how to scam people for months now! :D

As overshooting voltages resulting in spikes and ringing are known hurdles with hard switching pwm, adjusting rise and fall times offer a remedy to this.
I strongly suggest you stop providing any help at all to Paul Zigouras - even help as minimal as this. It would truly be awful if "EPC" were then able to make a controller that survived for longer than a few seconds at high voltage, because then it would have a much better chance of actually killing someone.
 

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OK, I'm now intrigued by this controller.

Partially by how the design manages to work at all with an inductive load. Also by how sloppy the construction standards are.

I've gone back and read the other threads, but would still like a few more pictures of the circuit boards.

We also built our prototype gate driver on a perf board (with two 9V batteries as our isolated gate supply). Even there our build standards were far higher than what I've seen in the pictures -- ours was compact, neat, symmetrical, had decoupling capacitors right next to the gate driver, and used TVS protection. We used that board only until we understood the behavior and problems, and then had a PC board made. I couldn't imagine driving around with a perfboard gate driver, let alone considering it suitable for a "commercial" product.
 

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Discussion Starter #7
OK, I'm now intrigued by this controller.

Stop! Stop! Stop!
Lets not be intrigued by anything engineer P.Zigouras does, did or plans on doing.

Let him answer all the questions :confused:- or be silent. :)

See Tesseract, he is absolutely right:
(I`m not up to date with blogging and so:)
Quote:
Originally Posted by Citystromer
Slowly I begin to doubt Mr. Zigouras knowledge about powerelectronics.

Slowly you begin to doubt?!? We've been doubting his knowledge of anything besides how to scam people for months now! :D

Hey I tried to be polite, was hoping to get some money back ...

Quote:
Originally Posted by Citystromer
As overshooting voltages resulting in spikes and ringing are known hurdles with hard switching pwm, adjusting rise and fall times offer a remedy to this.

I strongly suggest you stop providing any help at all to Paul Zigouras - even help as minimal as this. It would truly be awful if "EPC" were then able to make a controller that survived for longer than a few seconds at high voltage, because then it would have a much better chance of actually killing someone.
 

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There are plenty of examples around on how to design a robust, working controller. Not discussing a design won't change that. And a big part of designing a reasonable controller is writing the firmware.

I would really like to see pictures. Especially to see if the "control" circuit board is still a eBay LED PWM driver.

BTW, I note that the gate fuses are automotive "ATO" fuses. We briefly considered those, but they are rated for 32V. Many failures will result in full traction voltage being applied to unexpected circuits. In this case it could happen with a breakdown of the gate insulation from an inductive spike -- a likely failure mode. Even though we "know" that any arc in the fuse would be extinguished by an exploding gate resistor, it's still not a good design to use protection you know to be under-rated.
 

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Discussion Starter #9
Hi Citystromer,

Will you please clarify exactly what is in the photo and where it came from? Is it a controller made and sold by EPC?



Thanks,

major
How I got this photo, and what it is supposed to be:

On the 27. dec. I received this picture, explaining that this is how the new design of epc. I asked what the fuses should protect, the answer was: Sorry thy won`t protect the igbts, but they will protect the electronics.

On the 30 I received another (one out of many,many) mail from either Paul or his "sevice man" Will, that my order consisting of 2 igbt modules plus a complete set of electronics had ben shipped.
I`ve heared that before -

On the 31. I received another mail, again with the fuse pic attached as well as an installation description, in which he describes how to install everything. am I? :D

Did I see a patent pending for epc corp - maybe another 6 Million hush deal?:D
 

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Discussion Starter #10
Not discussing a design won't change that. And a big part of designing a reasonable controller is writing the firmware.

That`s right, emphasising discussion -

Since neither Paul, nor Will from EPC Corporation is willing to answer my questions -

questions to a product that I had bought,

may bee one of you guys, also potential customers of EPC corp. could bring light into the - so far dark sides of ep- controllers and chargers ratings, features, and standards used and selected.

Or is it: Our standard is to have no standard, and the ep 1000 is good for 2000A because I say so, when I say so?

Is it: Our World Wide No Fault 12 Month Manufacturer Warrenty is of such nature, that if 3000 Miles away it is very difficult to send replacement parts?
I have ben called a liar many times - please - try to find out what lies that were - it resulted in a big delay to get my warrenty -

Until totay I haven`t gotten anything yet - exept mails, mails, mails. friendly mails.

:)
 

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There are plenty of examples around on how to design a robust, working controller. Not discussing a design won't change that. And a big part of designing a reasonable controller is writing the firmware.
I don't know about there being plenty of examples around on how to design a ROBUST working controller... I mean, running a controller at 144V with parts rated at 200V, for example, might work, but it won't be robust.

At any rate, I don't quite understand your rationale that we might as well help this scam artist because he'll find help somewhere... It rather reminds me of looters during a riot saying they might as well help themselves to that flat panel TV because everything of value is going to get stolen or destroyed anyway. You go be the looter if you want; I'll stay inside with the 12 gauge at the ready.

Also, you can make a perfectly decent dc motor controller without a lick of code. After all, the Curtis 1221 and 1231 controllers are pure analog designs and no one would argue they haven't been a success.

BTW, I note that the gate fuses are automotive "ATO" fuses. We briefly considered those, but they are rated for 32V.
If you considered putting fuses in a gate driver then you need to stop designing power electronics, too.
 

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At any rate, I don't quite understand your rationale that we might as well help this scam artist because he'll find help somewhere...
I don't understand it either. It is like "a little knowledge can be dangerous", more dangerous than "no knowledge". It is apparent from what has been shown here that Paul and EPC have no knowledge about power electronics. It is easy to identify this lack of knowledge and therefore it presents less of a danger than if they had a little knowledge with which to hide their incompetence.

And should Paul read this, get your crap off the market!
 

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Discussion Starter #13
[we might as well help this scam artist because he'll find help somewhere... ]

I`ll agree 100% - not to help him, at all because: :mad:

Engineering has a lot to do with honesty.
No under rated part, no tiny misscalculation or error in design will listen to blah blah, not to prayers nor even priests- and then, all of a sudden, miraculously funktion.


If nothing else an engineer should know that.

This forum is a very good, low cost place to learn - it is not a place to bullshit and pretend. It`s a technical forum - a forum around power electronics

Helping this guy would be very unfair to the many real engineers and the ones to become one.

Lets just help him lo leave - goe away - far - far -
did we get rid of him already? - haven`t seen much posting from him lately.

:)
 

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did we get rid of him already? - haven`t seen much posting from him lately.
I have. He's been posting here and there in the forum. He does, however, stay clear of the EPC-threads. Maybe because he's finally realised that there's no way he can get out of them winning...

Unfortunately it hasn't stopped him from trying to scam new people. :(
 

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At any rate, I don't quite understand your rationale that we might as well help this scam artist because he'll find help somewhere.
Helping him improve the design wasn't what I suggested. I just wanted to see a few more pictures to understand what was in the box.

For instance, I suspect that the reason that inductive spikes aren't immediately killing the parts is that the IGBTs are being turned off slowly. Reeeally slowly. Creating a lot of heat with each turn-off event. Perhaps this is working because the PWM is at 150Hz, and there are 100x fewer turn-off events than with normal controllers. But you wouldn't run a real-life controller at 150Hz because of the heavy vibrations.
 

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Mr. Becker,

Would you please stop this and delete your posts about it, maybe before Paul sees them.

Thank you,

major
 
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