Medical devices and US 220V electrics

You need to work really hard to get that down to 1.5kW.

Is this peak or average ? Is it 3 kW or 3 kVA ? What power factor ?

It is not OK for 220-240 V outlets with 10 A fuses. You would have to install a dedicated 16 A outlet.

Any additional loads on the same fuse might eventually blow the fuse, a situation which is not appreciated in a hospital environment.

Not to mention what it'll do to the room temperature. What is it, a defibrillator for whales?

Cheers

Phil Hobbs

On a sunny day (Thu, 25 May 2017 17:26:01 +0300) it happened snipped-for-privacy@downunder.com wrote in :

It is 230V here these days. You could 3 phase power. Then you can have smaller filter caps too ;-)

I'd welcome a little more heat in hospital rooms. I was in one a week or two ago, they keep those things too cold for my blood.

George H.

The 3kW figure is peak, for maybe 15 minutes at a time. Average would be closer to a few hundred watts. Power factor should be close to unity, the loads are all either resistive or on the other side of a SMPS with active PFC.

My preference, for all the reasons that have come up so far, would be a dedicated outlet, but the marketing guys are resisting this as they think it creates a potential obstacle to the buyer. I can't understand this myself, we just acquired an environmental chamber which needed its own 32A 3 phase outlet. The cost of installing that was a tiny fraction of the unit itself.

Split phase 208VAC is not uncommon in NA - used to be standard for Kitchen stove, laundry drier or workbench hookups. Up to 20A/phase using 4wire armoured or flex cabling to iether duplexed 2x15 or 2x20A 120V wall outlets or single 15/20A outlets. They need separate but coupled breakers on each line.

If the power level you are talking about is already typically used in the application, then you should use the power couplers presently employed in the medical 'industry' for that application.

Equipment with that type of power consumption are not normally considered to be either portable or transportable, so a power requirement isn't a big issue. It is not likely to be included in any situation that has patient-applied parts, either, so the 'medical' part of it's labeling is likely only there to avoid commercial restrictions on similar products, like EMC........

RBlack wrote on 5/25/2017 8:05 AM:

No, 220 VAC is not common in the US, at least not in homes or offices. I don't know what hospitals might have. If you are talking about installing this in a lab setting, then providing 220 VAC is not really an issue, but it likely will require adding an outlet rather than just plugging it in.

All buildings have 220 VAC at the fuse panel, it is only distributed to the equipment that needs it like furnaces, clothes dryers and stoves. Office settings are often wired with both phases for the 110 VAC outlets with every other one on alternate phases. This helps to balance the load on the two phases. So there may well be 220 volts in a given outlet box, you just have to install a different outlet. In homes they only run three wires to each outlet box, AC, common and earth. So any

The bottom line is 220 VAC outlets are not commonly available, but 220 VAC is available in all buildings if you want to run a line for a new outlet.

That's why they invented blankets.

On a sunny day (Thu, 25 May 2017 16:56:40 +0100) it happened RBlack wrote in :

The solution is some Tesla batteries to even the average load...

You're describing split-phase 240V; two 120V circuits split from a

The _nominal_ voltage for _EU_ countries is 230 V. In order to get both 220 and 240 V counties, they just widened the voltage tolerances of 230 V so that it included both 220 and 240 V with tolerances.

With a SMPS, the current drawn will increase at 220 V and below, causing a lot more stress to the fuse.

Absolutely true, the smallest red IEC 60309 mains connector will handle 16 A at 230/400 V, so no big deal for a 3 kW load. However, the OP seems to have problems with the US market.

Why do you need filter capacitors after a six-pulse 3-phase rectifier, if you are going to feed a SMPS anyway. ?

Of course the 6 pulse rectifier has a horrible current waveform, so some kind o power factor correction might be needed.

Taking out from a 10 A 220 V (worst case) outlet for 14 minutes is stressing the 10 A fuse quite badly. A traditional fuse may survive a few load cycles, but eventually it will blow.

I have burnt my fingers several times, when replacing 10 A fuses loaded with three or four 1000 W lamps on a construction site :-)

Grounding arrangements in old (hospital) buildings can be anything. You might use some safety related arguments to demand a dedicated and properly grounded outlet.

Some hospital equipment needs backup generator power, or other uninterruptible power, and the cost of adding 'its own... outlet' may include much infrastructure.

Sounds about right. In my part of the world we're on 240V mains, but I do believe somewhere else on the planet there's a country that uses over

While technically it would be possible to have a 400/690 V Wye/Delta feeds, all the 690 V feeds I have seen are purely delta feeding big motors.

In Finland, there are several 1000 Vac delta distribution systems using standard LV hardware (ABC), but it is converted to standard

Yup, multiple power sources require jumping through a bunch more regulatory hoops. Hospital rooms generally have a 240 V outlet for portable X-ray, although most of those are battery-powered. I guess there's other gear that also needs a 220 V outlet. If the units are for soemthing else than patient rooms, I doubt there'd be any problem.

Jon

Actually, 120/208 Wye service is quite common in larger offices. Might not have it in the typical storefront-type building, but almost any multi-level office building will likely have that system. It gives lots of 120 V single-phase outlets, and 208 V between any two hots. Smaller air conditioners would have 3-phase compressors off the 208 mains. The building I work in has 120/208 Wye in the offices, 120/208 Wye PLUS 230 Delta in the lab space and 480 in the mechanical areas.

Jon

We have 120/240 3-phase, which is called a "stinger" service. That's

I suspect that any hospital could furnish 220 or 240 if equipment needs it.