HI Frank
Re Quote "When sizing gensets for hospitals (I know this is OT) we always looked to about 35% oversize including any large startup currents within the allowed load."end quote}
I would think that35% would be on actual measured loads OR CALCULATED MAX DEMAND allowing for a diversity factor.
It would not be 35% on top of ALL possible circuit loadings
ie EVERY THING BEING USED TO MAX at the same time.???
PeterQ
KFT said
10:54 AM Dec 7, 2013
G'day Peter,
We usually calculated the max demand and factored in some headroom for any high start currents. The loads were also measured at peak usage time. We found the regulation was better if the machine was not fully loaded. And there always seemed to be something that had to be added to the essential supply after all that work was done, which was a not allowed for load so I suppose we were building in some future proofing.
larger facilities often had two or more gensets with one specifically for "safety services" eg essential lifts and fire protection systems.
Newer sets have much better control systems these days so can be loaded up a bit more.
frank
PeterD said
05:44 PM Dec 7, 2013
GaryKelly wrote:
Blowed if all that a/h watts stuff will stick in my brain. I have a stick blender I use for my toothless diet - smoothies and stuff like that. It's a 250 watter. My house battery is an AGM 105ah and the inverter is 300 watt (max 600). If I use the blender once or twice a day for two minutes each time, will the sky fall in?
Gee there is a lot of waffle produced by amateurs in this thread. Nothing has been mentioned regarding power factor that will increase the required current. You blokes are missing things to throw up big time. Let's get back to the OP.
Gary has a 250 W device that he wants to use on a 300 W continuous duty inverter. I suspect that the motor in it will be a brush type and not a synchronous type. I would think that the 600 W peak power would start the device OK. With the duty cycle that Gary is going to inflict on the inverter I don't think there will be much in the way of overheating. The inverter will close down if it is overloaded.
Gary, you have the equipment there. This is not a case of what size inverter to purchase. Whip up a smoothie or two and see how it works. You will be holding on to the motor part of the stick so you should be able to feel if it is going to overheat when working on an inverter. If it does not like working on your inverter it will probably react the same on a larger inverter.
-- Edited by PeterD on Saturday 7th of December 2013 05:45:42 PM
SnowT said
06:05 PM Dec 7, 2013
Regarding hospital Gen set's..
I know of 1 particular hospital location where they Don't have enough Generator power to do what needs to be Done..
- does not help that they amalgamated 2 different hospitals on to the one site and thought that the backup gear they had.. would be enough..
Well the Back-up power they have is NO way near enough, and they need to shuffle the power usage.. The site has 4 set's of HV main's come into the place..
So no, Not all hospital's have enough Backup power..
Juergen
Aus-Kiwi said
07:56 PM Dec 7, 2013
You will find the 11kv feeds are possibly from separate substation ? Unlikely they will all drop out . The gen system could be for emergency and lighting ? Much lower load . Not ideal though !!
KFT said
08:10 PM Dec 7, 2013
Peter I thought Gary's problem had already been solved.
we were just going OT as this forum tends to do now and then.
and as you would know Pf is determined by the load and we correct it using capacitor banks. It is no hassle we just deal with it.
frank
mr glassies said
08:56 PM Dec 11, 2013
hmmmm now wondering if my 3000 watt 6000 watt start up inverter will be enough to run my washing machine microb wave and air conditioner . i have a smaller 1 for smaller demand but it should be ok
dibs
oldtrack123 said
10:40 PM Dec 11, 2013
mr glassies wrote:
hmmmm now wondering if my 3000 watt 6000 watt start up inverter will be enough to run my washing machine microb wave and air conditioner . i have a smaller 1 for smaller demand but it should be ok
dibs
HI dibs
With no details of any of those devices,brand /model number, NO ONE CAN ADVICE YOU
BUT unless the AIR con has a soft start feature it is very unlikely you would be able to use it
PeterQ
mr glassies said
06:28 AM Dec 12, 2013
aircon is ok its kick start lmdo
dibs
The dog lady said
11:38 PM Dec 12, 2013
GARY, I THINK IT MIGHT BE BEST FOR WORLD PEACE IF YOU JUST EAT YOUR BANANA UNMASHED!!
native pepper said
10:00 AM Dec 13, 2013
mr glassies wrote:
hmmmm now wondering if my 3000 watt 6000 watt start up inverter will be enough to run my washing machine microb wave and air conditioner . i have a smaller 1 for smaller demand but it should be ok
dibs
That will depend on their wattage/amp use and your battery storage capacity. If your inverter is pure sine wave, it will start them all, if it is modified sine wave, you may have problems. You need to work out your usage amperage, storage and recharge capacity, it's not the inverter which will be the problem, it's your ability to supply the inverter with enough energy to convert.
Re Quote "When sizing gensets for hospitals (I know this is OT) we always looked to about 35% oversize including any large startup currents within the allowed load."end quote}
I would think that35% would be on actual measured loads OR CALCULATED MAX DEMAND allowing for a diversity factor.
It would not be 35% on top of ALL possible circuit loadings
ie EVERY THING BEING USED TO MAX at the same time.???
PeterQ
We usually calculated the max demand and factored in some headroom for any high start currents. The loads were also measured at peak usage time. We found the regulation was better if the machine was not fully loaded. And there always seemed to be something that had to be added to the essential supply after all that work was done, which was a not allowed for load so I suppose we were building in some future proofing.
larger facilities often had two or more gensets with one specifically for "safety services" eg essential lifts and fire protection systems.
Newer sets have much better control systems these days so can be loaded up a bit more.
frank
Gee there is a lot of waffle produced by amateurs in this thread. Nothing has been mentioned regarding power factor that will increase the required current. You blokes are missing things to throw up big time. Let's get back to the OP.
Gary has a 250 W device that he wants to use on a 300 W continuous duty inverter. I suspect that the motor in it will be a brush type and not a synchronous type. I would think that the 600 W peak power would start the device OK. With the duty cycle that Gary is going to inflict on the inverter I don't think there will be much in the way of overheating. The inverter will close down if it is overloaded.
Gary, you have the equipment there. This is not a case of what size inverter to purchase. Whip up a smoothie or two and see how it works. You will be holding on to the motor part of the stick so you should be able to feel if it is going to overheat when working on an inverter. If it does not like working on your inverter it will probably react the same on a larger inverter.
-- Edited by PeterD on Saturday 7th of December 2013 05:45:42 PM
I know of 1 particular hospital location where they Don't have enough Generator power to do what needs to be Done..
- does not help that they amalgamated 2 different hospitals on to the one site and thought that the backup gear they had.. would be enough..
Well the Back-up power they have is NO way near enough, and they need to shuffle the power usage.. The site has 4 set's of HV main's come into the place..
So no, Not all hospital's have enough Backup power..
Juergen
we were just going OT as this forum tends to do now and then.
and as you would know Pf is determined by the load and we correct it using capacitor banks. It is no hassle we just deal with it.
frank
dibs
HI dibs
With no details of any of those devices,brand /model number, NO ONE CAN ADVICE YOU
BUT unless the AIR con has a soft start feature it is very unlikely you would be able to use it
PeterQ
dibs
GARY, I THINK IT MIGHT BE BEST FOR WORLD PEACE IF YOU JUST EAT YOUR BANANA UNMASHED!!
That will depend on their wattage/amp use and your battery storage capacity. If your inverter is pure sine wave, it will start them all, if it is modified sine wave, you may have problems. You need to work out your usage amperage, storage and recharge capacity, it's not the inverter which will be the problem, it's your ability to supply the inverter with enough energy to convert.