220 to 110 Volt conversion

Thanks Del,

The X-ray generator of the crystallography facility is rated at about 15 KW.

Kamal

Are you sure it is 15Kw and not 1500 watts? Most 110volt systems are intended to run on 15 amp circuits. That 150 amp at 110 seems a little off.

Yep!

Sure thats 15 KW. The X-ray crystallography facility is really huge.

Kamal

Jamal,

I have a stupid question for you, so please forgive me. Is your machine dual voltage rated?

GW,

That's a good point. How the heck did they get this through CSA, UL or whoever with that power requirement?

I am guessing, but it probably did not come from the USA or Europe, I bet it comes from China or Taiwan or even Japan.....lack of good regulations.....

Hi Andy,

The X-ray generator is RIGAKU, MICRO MAX -007.

Kamal

Looks like a decimal point is missing. Look at:

http://www.rigaku.com/generators/micromax007.html

Output power is only 1.2Kw.

Therefore input power of 1.5Kw is reasonable, and that is only 14 amps. About the same as my microwave oven!

The devil is in the details!

You are right GW., but the original poster was specifically asked this question and he gave the wrong answer!!! So it is hardly surprising that wrong "assistance" has been provided by others.

Thanks for clearing up this mess in such a good way!

Old saying "GIGO" = "Garbage In = Garbage Out"!!!

Ask and you shall receive:

The manufacturer is very willing to give detailed installation instructions to even an email query, so :

Some more data on the unit:

B. GENERATOR *Customer must supply transformer if the requested power is unavailable.
MicroMaxTM-007 HFM 200V
20Amp
3Ø
60Hz

...and Mr original poster, is the 60Hz a problem for you?

Do you only have 50Hz?

Is the machine dual frequency or not???

The end to this nail biting tail (sorry Tale!) will be brought to you by CR4 as soon as we can!!!!!

Signed,

The Man in Black

(who I used to meet quite often on the train from Burgess Hill to London over 30 years ago!! his real name was Valentine Dyall, a really nice Guy in real life and totally unrecognized by all of the passengers, except of course MOI !! Unforgettable voice, once heard never forgotten.)

Valentine Dyall

Well... Andy, there was a mix-up and I OWN THE RESPONSIBILITY.

I appreciate the time and pains taken by the guys to answer my query and in the same spirit, would accept ciritisism also. BUT, my original concern was only, 'Wheter output of a UPS can or at all, should be connected to a stepdown transformer'.

Kamal

Why use a UPS? The unit is normally only used for a few seconds at a time. A three phase transformer for your application is dirt cheap.

Thanks GW, the end user says UPS is absolutely essential just to avoid even the remotest possibility of accidental power failure, besides the computer remains powered up for longer periods and sometimes unattended.

Kind regards,

Kamal

Put the computers on the UPS.

Seperate lighting, AC, and other non-essential loads from the UPS.

X-ray is only for a few seconds and not continuous operation, so take it off the UPS.

If the power system is so unreliable that they are facing hours of routine outage, then only a DG set is worth looking at.

I just can't see the necessity of putting the X-ray on UPS. (For example, you go to the dentist, power goes out, you just wait until it comes back for your x-ray). The samples that will be x-ray'd in the machine you mentioned can definitely wait a few minutes for the power to come back. The sames will be just a gram or two.

I can understand they would not want their computers to crash.

GW,

X-ray diffraction work is dealing with highly a collimated and stable beam of X-rays, filtered to a single wavelength (the one I remember was Molybdenum k-alpha). The data are taken over hours of time by a machine in which the sample and detector are each being moved over multiple axes. These types of machines usually have the X-ray source kept on continuously to maintain the stability of the source, with a shutter to block the beam when not measuring. Any time you enter the room the equipment is in, you must have a Geiger counter with you to check for stray radiation (it can happen if, for example, the trap which normally absorbs the primary beam gets displaced and the beam then strikes and diffracts off other surfaces).

The sample is held in position on a tool called a goniometer, which can adjust each of the three angles of rotation to a precision of about 5-minutes of arc, and each of the three axes of translation to a precision of about 0.05 mm or better.

People talk about "garbage in, garbage out", well this is one field where any garbage with the incoming power supply will cause garbage with your measurements. If you want good data, ensure that the front end is reliable! Put the whole thing on a UPS. If you can afford it, add a ferro-resonant constant-voltage supply.

--John M.

Assuming that your local supply is 60Hz 8you have not mentioned this either way.....

A UPS with a 3 Phase output and enough battery power to supply 20 amps for even one hour is going to be very expensive. If at 220 volts, it will still be expensive.....

I have not compared prices recently, but my guess is that a quality DG will cost less and give a proper sine wave output, also it can be tailored for both voltage and frequency needs. Plus it will not need a battery bank replacement every 18 months either......

eg. A lower cost of ownership.

To answer your question; yes, you can use the step down transformer after the UPS but you have to de-rate it considering the output wave form may not be pure sine wave. I am assuming that the output of the UPS is AC, single or 3 phase. Since the load is small, only 1.5 KW, a 5 kva step down xformer shall do the trick. That is the easy part, the problem is whether your UPS can withstand the inrush current; if you have already bought the ups check if you have current limiting in the output. This is where you can get into trouble.

As other posts have suggested there are other ways to skin the cat; if the supply is not reliable enough buy a small portable generator and feed your x-ray machine with an automatic switch over or manual.

If you do decide to use the transformer, my preference will be to use it before UPS unless you have already bought the ups. The only thing you & your end user have to decide which of the two solutions (gas/diesel Gen or UPS) gives less hassle to operate & maintain besides the installation cost.

Hope this answers your question.

JMSK

PS. Posting wrong or incomplete information can only lead to ill advice and be counter productive.

Tnaks so much guys.

The discussion has not only enlightened me but your comments have been immensely useful for arriving at a logical decision. We'd now go in for a suitably de-rated stepdown transformer after the UPS. I hope to conclude the pre-intallation/commisisoning requirements within this week.

Kind regards......

Kamal

I gather your source (power supply) is fairly reliable and the interruption does not last more than a few minutes & that you have sized the UPS batteries to outlast the power interruption. If the power interruption is more frequent or lasts longer period of time, you have to size batteries to allow them to charge (frequent interruption) and AMPHOURS to cover the load during interruption. This is another point you should take into consideration when using / or sizing a stepdown transformer after the UPS, the size of the no load current will have to be fed by the UPS (batteries) during power interruption. During long power interruptions this could be significant.

Good luck.

JMSK

The main question was, "where was it built?", but thanks for the other infos, but we need this question answered first!

Is the machine brand new or not?

Do you still have a manufacturers warranty if new?

Have you approached the manufacturer for a possible "power front end replacement"?

Update

The above infos have been rendered "out of date" as the machine in reality only takes 1.5KW and not 15KW as earlier stated and is also 3 phase, so no problems with a UPS or DG provided the Frequency is correct or adaptable....

Does the generator require the current on a steady state basis, or is there an on time, and a duty cycle? This could make a great difference.

If doing a stepdown, I would do it before the UPS.

If the UPS is a full-isolation system (no connection between the incoming line and the output), it will work. However, since you don't have a normal 110V supply, the x-ray generator will be unavailable during UPS maintenance/repair.

I agree with TVP45. For reliability and continuity, I would install a stepdown transformer (~25KVA) before the UPS, and purchase a 110v UPS. Ideally, the UPS should have a static switch bypass system for bumpless transfer between the regulated output and the line.

I disagree.

Many years ago I did a large similar exercise for Seagate in Northern Ireland. They had a mixture of 110 & 230 volt equipment. We standardised on 230V UPS and fitted step-down transformers on the output. Worked well.

The enemy of UPS outputs is current. The thyristors or IGBTs need to handle twice the output current at 110volt. This tends to cook the poor old silicon.

However that's a hell of a load for single phase. Tricky thing is that the input power factor is proportional to load, and at 50% load can be as low as 0.7 (but depends on manufacturer). So

15 kW output + 20% margin = 18 kW

+ losses 10% = c. 20 kW

+ battery charging load 20% = 24 kW

@ 0.7 pf = peak 34 kVA which is nearly a 160amp single phase supply. Yikes.

Thanks Babyguinness for the comments - actually I'm the end user. The power requirement for the Xray generator, a 3 phase instrument, is 220 V per phase and 12.5 Amps per phase.

The generator is of US make and does not have a dual Volt capacity built in. More than 3 dozen such generators are being used in the sub-continent, which are functioning well.

The input 220V 3 phase line is connected to a 15 kW UPS 3 phase etc. The output is then stepped down to 110 V and supplied to the xray generator. Subsequently the voltage is stepped up in the generator to kV (~40 kV) so the current aspect goes down drastically - the silicon will not burn :-)

Thanks Kamal for initiating the discussion

hope this helps

AT LAST!! Proper infos!!!

What a difference real and correct infos makes.

Although you still forgot to mention frequency, which is now the most important question of all:-

1) What is the frequency requirement?

2) Is it a dual frequency machine?

Once the frequency problem has been correctly addressed, there should be no problems in connecting to the mains.

If the mains in your area is not reliable, i see no other possibility other than running only on a properly rated DG personally....

The company that built this machine really did not have a clue what they were doing with regard to electrical power when it was built if what you say is 100% true.

Neither did the person who ordered it either have a clue about electrical power when ordering the machine!!

I would say go back to the Manufacturer and ask what other possible power "front ends" are available before doing anything more. As a proper front end may fix all your problems in the cheapest possible way......in the end!!

To my mind, a machine that needs that much power should have a 3 phase input transformer at least......preferably at 380 volts to keep currents down and to be able to connect easily in a 220 volt system.....!!!

You did not mention frequency, generally speaking 110 volt AC devices are also 60 Hz, but 220 Volt areas are often 50Hz, has anyone looked at this point too? If there is also a compatibility problem in frequency, then the best alternative I feel is a 380 volt 50 Hz 3 phase to 110volt 60 Hz Single phase rotary converter.....I would imagine a special build (but I do not know my way around such machines anymore.....)

Talk about "the Blind leading the Blind!!" Needing at least 140+ amp connection at 110 volts, not including any "inrush current" requirements!!!!!

My only other thought is that maybe it is possible to supply 110 volts to the machine via separate connections from a properly built fuse panel, so that there are say 8 or more separate connections to the machine (Beast?), each taking 20 amps or less.....? What happens if one or more drop out is another question!! They probably need to be interlocked in some manner!!

What a major screwup!!!

Hi J Kamal,

If what you described is correct, Andy Germany is right. It seems like a royal screw up. Besides the voltage compatibility problem, you probably have a room full of batteries, a very large room at that. It would be interesting to see what the name plate says. Print the name plate if you can, do not leave anything out.

Either the supplier did not know what they were doing or the buyer had no clue what they were buying.

To answer your question, what voltage corrector are you refering to? If it is a transformer you are thinking about, I would not do that unless you are sure that the output wave form is a sinusoidal. If it is not pure sinusoidal, the transformer will heat up, lower output, higher losses, poor efficiency. As someone suggested earlier, it is always a good idea to step down the voltage before feeding the UPS.

JMSK

Why not use a transformer (single phase) instead of a UPS? Do you need to keep this equipment running continuously? Is your power system unreliable?

Reply #9 sounds good to me. The machine requires DC power at a certain voltage, so purchase an input transformer (front end) for 220 vac to feed the rectifiers with the correct secondary voltage right from the factory that made your equipment. It'll certainly be cheaper than a set up for 110 vac just in the copper alone.

I sure love this site. Some of you guys really know your stuff!

For my practical, shade tree engineering approach, the motor/generator (actually alternator) sounds like the most cost effective solution. A diesel driven unit if your mains are unreliable.

I'd locate a suitable 20kw, 120 VAC alternator, mate it with a motor of the appropriate horsepower & voltage, assemble mains control in and the 120 VAC fused disconnect out.

If the UPS isn't of prime importance, I would try to live with the inherent time delay of voltage loss should mains fail due to inertia of the motor/alternator armature(s). If the output current is only 10 to 20 percent, you may get 15 to 30 seconds of usable power after mains cut out.

Good luck on that cost effectiveness thing!

Regards !

X-ray units need well matched Input Impedance of Power line as the Exposures are very fast @ High power for Short-time [mSec ].

They normally [if hi-power units ] need new power line well matched by Supply Co.

For small units Step-down transformers may handle.

For UPS the problem lies in "Exposures are very fast @ High power for Short-time "

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