size of generator

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At the animal hospital my wife techs at, they are wanting a generator. They have an X-ray machine that has a momentary output of 140 amps at 220 volts. It dims the entire clinic when first engaged. Since this is the biggest power draw there, what are the watts needed to support this draw?

 

[Mendonsy]

They would need about 32kw to support just that X-ray not including the rest of the facility. A full 200 amp service (probably what they have now) would require 46kw.

 

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They would need about 32kw to support just that X-ray not including the rest of the facility. A full 200 amp service (probably what they have now) would require 46kw.

So just for the X-ray machine, they would need an output of 32,000 watts?

 

[Mendonsy]

YEP! The math is simple enough, Watts = Volts * Amps.
The question is do they really need to use that Xray machine when running on a generator?? The rest of the facility might run on a 20kw generator.

 

[KWentling]

This is a case where you would want to get an expert involved in choosing a generator. It may not be as simple as amps x volts. Maybe some inrush to consider and will the generator supply clean enough power for the electronics.

 

[buickanddeere]

This is a case where you would want to get an expert involved in choosing a generator. It may not be as simple as amps x volts. Maybe some inrush to consider and will the generator supply clean enough power for the electronics.

Power factor has to be considered . Start multiplying volts X Amps and the number will come out different than the watts for inductive and capacitive loads.
Is X-raying critters going to be a priority when utility power is down ?
What are the other electrical loads?
A generator will have more bog and light dimming than utility power because of governor response time.
This looking like at least a 50KW generator.

 

[Industrial Toys]

That really sucks! It's not good having a generator not loaded up. Natural Gas or LP would probably be a better choice for this application then diesel.

A Vet Clinic bought my old Onan 15KW PTO unit.

 

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Power factor has to be considered . Start multiplying volts X Amps and the number will come out different than the watts for inductive and capacitive loads.
Is X-raying critters going to be a priority when utility power is down ?
.

This is a pertinent question and is one the hospital needs to consider. 2 yrs ago the power went out there for 5 days on a wind swept 27" dump. 5 days w/o an X-ray machine proved to be rather exasperating for this company as X-rays are a first line course for about 40% of what comes into the clinic. Between cancer, what animals eat that they shouldn't and internal abcesses and disease, it's used quite bit and just about every day. An 8000 watt generator powered the rest of the clinic at that time. A stand by unit this large is around 14K. Hook up is probably another 5. They have to decide about this expense by comparing what they lost in turn away business along with the chances of getting another 5 day loss of electricity .

 

[SPYDERLK]

This is a pertinent question and is one the hospital needs to consider. 2 yrs ago the power went out there for 5 days on a wind swept 27" dump. 5 days w/o an X-ray machine proved to be rather exasperating for this company as X-rays are a first line course for about 40% of what comes into the clinic. Between cancer, what animals eat that they shouldn't and internal abcesses and disease, it's used quite bit and just about every day. An 8000 watt generator powered the rest of the clinic at that time. A stand by unit this large is around 14K. Hook up is probably another 5. They have to decide about this expense by comparing what they lost in turn away business along with the chances of getting another 5 day loss of electricity .

It sounds as if the xray has an initial surge. What condition causes the surge? Is it only on startup, or does it occur as the xray is taken each time? If its only a startup surge - charging a capacitor bank or something - maybe the machine can be soft started. This would lower the 140A max drain and lengthen the time only slightly.

 

[ultrarunner]

Also sounds like the x-ray is pushing the capacity of they utility power...

At the 32,000 square feet Out Patient Surgery and Imaging Center there is one 600V 1200 amp 3-phase breaker.

The Emergency Power is supplied by a 600V 150 amp Emergency or 125 amp Prime rated Diesel 3-phase generator.

No lights ever dim....

 

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It sounds as if the xray has an initial surge. What condition causes the surge? Is it only on startup, or does it occur as the xray is taken each time? If its only a startup surge - charging a capacitor bank or something - maybe the machine can be soft started. This would lower the 140A max drain and lengthen the time only slightly.

99% of an X-ray machines electrical energy is converted to heat. There are huge electrical filaments in the X-ray machine that warm the X-ray tube. Heating a cooled down tube is where most of the energy draw is used. Once warmed up, amperage is cut more than half. I do not know if a slow start would burn anything out in the machine itself or greatly lengthen start up time.

 

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Also sounds like the x-ray is pushing the capacity of they utility power...

....

I believe it pushes the capacity of their service.

 

[buickanddeere]

It's going to cost but 50KW will be required. As previously stated a gas, LP or natural gas prime mover vs a diesel which will have too low of stack temperatures due to the under loading .

 

[Industrial Toys]

I was thinking along the same line. Maybe a different X-Ray machine or large commercial UPS. So what that's worth? Maybe 200G for an X-ray machine, or 20G for a Big UPS, that likes fresh sealed batteries every few years. Sounds crazy, but I would go on E-Bay and buy a separate genset just for the X-ray machine. Some nice, low hour X-Military unit.

 

[ultrarunner]

Just sold an older hospital x-ray unit for 5k... with table and controls...

Older medical equipment often costs more to move and install than to purchase.

The trend is totally away from film... all digital which means no longer needing a dark room and chemicals.

 

[SPYDERLK]

99% of an X-ray machines electrical energy is converted to heat. There are huge electrical filaments in the X-ray machine that warm the X-ray tube. Heating a cooled down tube is where most of the energy draw is used. Once warmed up, amperage is cut more than half. I do not know if a slow start would burn anything out in the machine itself or greatly lengthen start up time.

Is the high amp draw only present when 1st turning it on or does the hi amp draw cycle periodically during use?

 

[Industrial Toys]

Digital imaging has taken all the charm out of it. Experts in white coats clipping negatives to illuminated screens for the big diagnosis.

That must be some large tube, to take that kind of heating.

 

[ultrarunner]

The imaging unit uses over $3,000 in electricity each month for one MRI and one CT machine in 1200 square feet...

 

[Industrial Toys]

Unbelievable! It would cost ten times that in Ontario!

This must result in some serious AC loads in the summer as well. A double wammy.

 

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Is the high amp draw only present when 1st turning it on or does the hi amp draw cycle periodically during use?

The 140 amp draw is momentary. The largest draw is when they first turn it on in the morning. If the tubes cool down (anode and cathode ray) there is the momentary draw once more. Actual imagery is only a flea's worth of electricity at 300 Ma.