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Patfig

Any Electrical Gurus In ( 3 Phase)

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Hi all,

I am moving into a new business unit that is wired up with a single phase supply.

I have been offered a piece of equipment that requires a 3 phase supply but there isn't any on site.

This piece of kit would need to be running permanently and only turned off for maintenance probably yearly. It would also benefit form a nice smooth UPS supply

Does anyone one have any suggestions or should I forget it?

PF

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Because you splitting a single phase, I'd make sure that any invertor you buy is rated at least 25% above the loaded rating of your equipment. Note also that invertors are sometimes, actually very often, output max rated for a temporary supply. e.g. Rated at 1.4kW at 220V, but are only rated to supply 6A for X amount of seconds/minutes, 4A continuous. Obviously, do your homework, and work with the 'continuous' rating.

3-phase UPS are remarkably expensive. Best you keep the UPS on the single phase side. This creates it's own problems, again, with the effective rating of the UPS.

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How much would a 3 phase supply cost? Call your electricity supplier for a quote. If there is a 3 phase supply to the road, this could be under £2k. Of course, if this is in the middle of nowhere and there is only a single phase high voltage supply to the area, then it could cost £20k.

Industrial quality phase converters are expensive, as are industrial quality UPS units.

If your 3 phase requirement is only for motor drive, you can use a variable speed motor drive for phase conversion. However, these are generally not able to convert a 230V supply to 400V,and require a lower voltage motor. Also bear in mind that this type of drive doesn't work well if your equipment has electronics in it.

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Hi all,

I am moving into a new business unit that is wired up with a single phase supply.

I have been offered a piece of equipment that requires a 3 phase supply but there isn't any on site.

This piece of kit would need to be running permanently and only turned off for maintenance probably yearly. It would also benefit form a nice smooth UPS supply

Does anyone one have any suggestions or should I forget it?

PF

I have three phase in my base, although I don't normally use it.

First of all, a three phase UPS is going to be huge and massively expensive. Why do you think it will need a UPS ? Normally in industry three phase is used for motors etc. UPS on these is not usually necessary. If it needs a smooth supply and not the ability to stay on, then you need maybe a mains conditioning unit rather than a UPS.

Secondly, unless you are talking about a massively expensive piece of equipment, the cost of putting in a dedicated 3 phase line is probably going to be more expensive than buying the equivalent single phase bit of kit new.

If you go down the AThirdWay route and get something to convert single phase into three phase, then obviously you need expert advice on the power requirements to make sure the conversion is correctly spec'd.

I would refer to the "False Economies" thread.

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When it comes to power protection I like to think of 3 categories.

1. Asset protection. Protection of expensive equipment against sever power problems: voltage surges, lightning, etc.

2. Process interruption. Protection against the costs of an aborted process - for example a destructive analysis on an irreplaceable/difficult to replace sample.

3. Protection against loss of production. What happens to your business if the power is out for 24 or 48 hours?

1 requires surge protection and/or power conditioning.

2 requires a UPS with battery autonomy sufficient safely to halt the process.

3 requires a generator.

A UPS, particularly a dual conversion UPS can also provide excellent asset protection, but the UPS itself is often expensive and its own asset protection may be appropriate.

Some equipment such as pulse lasers, RF or microwave equipment, X-ray equipment or magnets may have special power characteristics which need expert advice from the UPS vendor or a consulting engineer.

Don't forget to consider the demands of ancillary plant. Chilled water, compressed air and air conditioning needed to support your equipment may also need power protection.

Ultimately, your choice of protection and type of protection depends upon a cost/benefit analysis of each component.

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Mass spec

Look! It will NOT come in handy!! :blink:

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Its a piece of very sensitive scientific equipment

What is the power consumption for the Mass Spec?

In general terms firms would only design something to use three phase if it needed the additional power or you if it had a fairly chunk motor that they wanted to run more smoothly than could be achieved with single phase

You can get close 3 times the power of a normal single phase from a 3 phase supply (depending on the power factor cos(Φ) which is the difference in phase between the current and voltage on a line.

Basically Wapplied = 31/2 U I cos Φ

[where U is the voltage between the phases (415V) (versus 240V between Phase and return). Wapplied = real power (W, watts) U = voltage (V, volts) , I = current (A, amps) ]

If the Mass Spec doesn't need more than say 6kW you may be Ok with some sort of phase convertor, but if it it needs more then it may be an issue. Also the quality of the converter may be important, you can get one for £200, but I am not sure how good that would be. But my gut feeling is that if you can a 230V / 32A input single phase, then you should be in with a good chance unless the the Mass Spec needs 7kW or something which

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Can you pull out of the business unit deal and find another as industrial units that have been a car/engineering workshop at some point in their lives, and already have 3 phase, will be ten a penny?

I've got three phase in my man cave and it was very expensive to put in as oddly no-one nearby seemed to need it for weekend DIY projects (I needed it for a set of vehicle post lifts). In general I would say that the majority of stuff that's three phase is because it probably needs it. I have upgraded a lot of workshop kit to three phase and have recouped a bit of the cost as they tend to go cheap as no-one wants three phase. I guess the compressors / pillar drill / lathes probably do have acceptable single phase versions maybe.

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