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Quick Variable DC Power Supply From 400VAC

01/04/2016 8:59 AM

Congratulations into 2016 fellow CR4s. Let me have a straightforward practicable approach of getting a 50Amps, 0-100VDC (variable) power supply from an AC 400V 50Hz 3 phase source. Thank you for coming forward with a solution

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#1

Re: Quick variable dc power supply from 400VAC

01/04/2016 9:03 AM

Simple. Use a search engine, such as Google, to find suitable candidates. Once the required one has been selected from those available, the rest can be done with a phone call and a credit card.

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#19
In reply to #1

Re: Quick variable dc power supply from 400VAC

01/20/2016 4:16 PM

FY-5008C K3Y-1050

((?? should i be here . . . nope!))

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#2

Re: Quick variable dc power supply from 400VAC

01/04/2016 9:26 AM

A straightforward practicable approach of getting a 50Amps, 0-100VDC (variable) power supply from an AC 400V 50Hz 3 phase source, is to do as PWSlack has indicated.

My 9 year old finds many things this way every day.

Or, use the Products and Suppliers link at the top of this page.

Good searching.

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#3

Re: Quick variable dc power supply from 400VAC

01/04/2016 9:30 AM

What is the application?

Electrical requirements for a 0-100VDC power supply feeding discrete solid state controls is quite different than those for a 0 -100VDC power supply controlling a motor or for a tramp iron magnet monitoring a conveyor belt or for a welding machine.

You must identify the operating load characteristics of the application such as:

1) Anticipated Service Factor and/or Duty Cycle: (100%? 80%? 60%? ?)

2) DC waveform quality requirements? (How much ripple is allowed/acceptable? Noise limits?)

3) Required torque curve for attached load(s)? (Key operational points where maximum torque/amperage is required.) (If for a motor: Max current at what RPM?)

4) Allowed footprint size dictated by the application?

A basic rectification unit will consist of an adequately sized 400-120VAC transformer with a properly sized rectifier system inclusive of a DC control system with proper filtering assembly.

Depending on the electrical system characteristics of the available 3 phase source and the allowed installation footprint size, the rectification and variable DC control could be a simple three phase rectifier bridge with a RLC filter and a variable resistor or the best option might be to purchase a packaged unit that utilizes IGBT control.

There is no way for any remotely located person to answer your question without more input and/or visiting the site.

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#7
In reply to #3

Re: Quick variable dc power supply from 400VAC

01/04/2016 12:54 PM

These power supplies are ready to use for sale.

While IGBT is a clever solution, even with high quality (read expensive) "trigger" or "steering" modules they are causing us lots of problems.

We tried to use it for battery formatting power supplies and even have put more batteries i series to not have to cut down to 100 Volts.

Our system is designed to work straight on V max but the IGBT's seem to have problems in this application.

I am also very interested in a follow up, sonce our problem isn't solved either.

We had better results with Thyristor 3 phase bridges, but IGBT's are more easy to trigger. (linearity)

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#4

Re: Quick variable dc power supply from 400VAC

01/04/2016 10:02 AM

So many times I try so hard to contain my mad outbursts originating from some assumptive respnses I get when I post here. I am sure of what I need and had stated it clearly. Let me welcome the good response that suggested I get an IGBT controlled power supply, I wish I can but I am in Nigeria-Africa where availability of such updated smarter controls are a bit hard to get, replace or maintain and I don't seem to have a trusted partnering technical personnel whith whom I can source my materials. If I may ask, supposing I use an existing VFD and connect the variable output to a 3 phase diode bridge, can I get a clean variable dc supply from the diodes output. I intend to control or replace an existing scr 3 phase bridge with the output originally dedicated to the exitation of a dc constant current generator. Can any experienced person suggest a quick solution. Cheers

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#5
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/04/2016 11:14 AM

So it sounds like you should be looking for a Procurement Resource rather than individual components. I know the below isn't in Nigeria, but they are in Africa and might be a really good place to start:

http://www.wesco.com/international/angola.htm

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#6
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/04/2016 11:37 AM

<...use an existing VFD and connect the variable output to a 3 phase diode bridge...>

The circuitry needed between a VFD and variable voltage DC output terminals is a little unclear. Please explain how a variable frequency is supposed to be converted into a variable voltage when the VFD is looking for feedback from the motor, which is absent, in order to operate correctly (rhetorical question - NNTR)?

How did the telephone calls with the equipment suppliers go, then? Surely someone takes a credit card payment for overseas shipping?

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#8
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/04/2016 10:46 PM

Please excuse us if we seem to be mocking you. We get MANY questions here by many people who are either lazy or just looking for homework answers. It has given us all a bit of caution when a question comes across with little information and a potentially complex answer.

A little more background info and an explanation of the application would help. It is better to ask a long question up front than a short one, because a short question will usually have us all looking for short answers!

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#9
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/05/2016 12:14 AM

The following contains no malice, sarcasm, rudeness, dual meanings, subliminal messages or Bxll Shxt.

The better the question the better the answers. We have to understand the problem stated in the question as good as you know or better. If not, the quality of the answer is going to be poor in respect to what you wanted. We are not mind readers. Sometimes I have difficulty reading my own mind let alone yours.

If you had included some of what is in #4 in the original question you would now be a more satisfied poster. As to the quality of the answers, you have no one but yourself to blame. Don't get P.O.'ed, get better. An axiom to this in the educational field is "The quality of an education is not how well the teacher taught it, but how well the students learned the subject."

So many times I try so hard to contain my mad outbursts originating from some assumptive respnses I get when I post here. I am sure of what I need and had stated it clearly.

Clearly is determined by the listener or reader, not the author.

Good Luck, Old Salt

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#10
In reply to #9

Re: Quick variable dc power supply from 400VAC

01/05/2016 12:16 AM

GIGO

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#11
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/05/2016 2:31 AM

replace with a new DC thyristor bridge.

ABB has the DCS800 series, Rockwell has the Powerflex DC series.

I am partial to the ABB drive, but we use about equal quantities - customer's choice.

Should cost about $2500 Canadian for the basic drive that you put in a cabinet. You have an existing system so it is just a retrofit.

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#12
In reply to #11

Re: Quick variable dc power supply from 400VAC

01/05/2016 2:45 AM

ABB in Nigeria:

http://www.abb.com/references/default.aspx?db=db/db0004/db001502&c=10c6f187318b8efac1257249005e4fb7&att=Country&value=Nigeria

Best of luck.

suggest as a starting point: DCS800-S01-065-05

You can use this drive for motor armatures, motor fields(+options), Magnets, etc.

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#16
In reply to #4

Re: Quick variable dc power supply from 400VAC

01/05/2016 2:00 PM

We wouldn't have to be so assumptive if the original question contained the necessary information to give you a good answer. Good day.

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#13

Re: Quick Variable DC Power Supply From 400VAC

01/05/2016 2:48 AM

Thanks "Old salt" and all concerned. Let me try to explain again my situation: I am trying to maitain an equipment originally manufactured by Germany in 1960s, inside this equipment is a diesel engine rotating a dc alternators, the output of thes dc alternators are connected in series with dc motor loads, the series connection is interconnected with interlocked switching contactors to enable either the generators or the motor loads engage or disengage the series circuit. Now this is a summary-brief explanation of the application. My problem is that the generators spin without any desired current output that can be used to engage and run the motors in the same closed circuit with it. On investigation I discovered that the generators 30A dc exitation circuit is malfunctiong. I went further to discover that the malfunction of the exitation circuit is powered by an AC 340V 3 phase connected into 6 thyristor 3 phase bridge rectifier,upon closer inspection, I tested the F thyristors with a dc on/off latching device and confirmed them ok.My core problem is coming from the electronic circuitry driving the 6 thyristors, I have tried repeatedly to replace any visible solderable resistors,transistors, capacitors and many more surface electronic components but upon test, the dc output continued erratic output. I have begun a search for another circuit from this 2016 to replace this scr circuits coming from 1960s. I feel there ought to be a dependable thyristor firing circuit in wide circulation that can cater for a thyristor 3 phase variable output dc rectifier. If I can lay my hands on such dependable circuit, it will save me the time and labor of the complexity of this repeated failed fixs I'm going through.However, if for yet unknown reason(s) such thyristor circuits are not available to me here in Nigeria-Africa, I intend to welcome another friendly method of generating about 0-60A dc current from a 340VAC 50Hz 3 phase source. I can fabricate a portable 250VAC ---0-60A DC, half wave variable output , but my ac volage source is limited to 340V or 400V AC. I consider my challenge to be excellently dealth with if I can lay my hands on a portable versatile thyristor-scr firing circuit with instructions on how to improvise and incorporate it into my existing system. Thyristor 3 phase bridge variable power supply is a common circuit and I honestly feel any man with experience of its core firing circuitry or board here and willing can share useful information with me. Thanks for making me long explain, I can explain further if need be, but I don't have much time on my hands for this one challenge

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#14
In reply to #13

Re: Quick Variable DC Power Supply From 400VAC

01/05/2016 2:53 AM

The cost to buy new is so low it does not warrant the time inventing.

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#15
In reply to #13

Re: Quick Variable DC Power Supply From 400VAC

01/05/2016 5:10 AM

If the circuits you want are not available in Nigeria as you say, how on earth did the one you are having trouble with get there in the first place?

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#17

Re: Quick Variable DC Power Supply From 400VAC

01/05/2016 4:10 PM

Thank you "GW" ABB's DCS800-S01-065-05 is a 230---525VAC, three phase 65A converter. It should be perfect if the programmability can be preset to about my 20A constant current with a current transformer sensing feedback from my load. The only thing standing between me and this product is ABB's cost. I shall apply for their quote with any of their agent in my locality. Meanwhile I'm not thouroughly satisfied with my poor grasp of how I can be my own OEM, so, I shall be studying "SHOCKHISCAN" links. Just in case ABB's DCS800-S01-065-05 fails again.

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#18
In reply to #17

Re: Quick Variable DC Power Supply From 400VAC

01/05/2016 8:36 PM

If you go through ABB system group or an integrator you will pay a premium, but it will work

The Part Number I gave you is a stock item.

I do not know your engineering skills, but if you want a 20amp regulated output (versus a voltage regulated output) the drive has its own internal CT's, and you can set the parameters for "20A" output. It will then regulate the output voltage to achieve the 20 amps.

My company is a systems integrator for drives - what is almost trivial to the engineers in house can be daunting to the novice. I do not know your skill level, but the manuals are downloadable (free!) and pretty good. Take a read through. Suggest setting the voltage ref to maximum rated and the Current (torque) limit to the desired amps. The volts will increase until the output amps hit the set current limit. This limit can be steered by an analog input, or if a communication module added, from an external digital ref.

Read the firmware manuals - gauge that against your own capabilities. If you have an EE background (or a good industrial electrician background) you should be able to figure it out. If you don't have the background it will be "all Greek" for you.

Best of luck.

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Users who posted comments:

Anonymous Poster (1); Brave Sir Robin (1); ci139 (1); Deefburger (1); dvmdsc (1); GW (4); JavaHead (1); lyn (2); old salt (1); PWSlack (2); SHOCKHISCAN (1); Ukeje (3)

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