inverter system vs. ups

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sam34

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1. What is the main different (electrically) between the inverter system (emergency lighting)and the UPS system?

2. Do I have to have ATS upstream of the inverter system (Generator and normal power) or does the inverter system comes with built-in ATS? and if I have the ATS upstream of the inverter, with built-in ATS in the unit, is there any advantage of that?

Thank you all in advance.
 
Re: inverter system vs. ups

sam34 said:
1. What is the main different (electrically) between the inverter system (emergency lighting)and the UPS system?
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An inverter could be a part of the UPS system, ie a UPS system that relies on a battery to store power until it's energy is needed - BUT, the DC would need to be changed to AC~by the inverter.
 
An inverter system used for emergency lights works similarly to a battery pack emergency light. It senses loss of normal power and switches the light over to battery power. There maybe a short period of time that it takes for the unit to switch to battery power. A UPS provides, as it's name implies, an uninterupted power supply. Not only does the system provide power conditioning it will switch seamlessly from normal to battery power. On a large UPS system, this will allow a back up generator time to start and come up to speed with out any interuption in power. Usually after a timed period the UPS will switch off of battery power and on to generator power. This type of system is need for sensitive equipment, computers, etc. that may lose information if the power were interupted even for a split second.
 
I am not sure but I think he asking about both a typical UPS and an Article 700 Emergency Inverter supply.

The job I am doing now has as its emergency lighting back up source a panel that is called on the prints Inverter Panel, it will be fed from a 'normal' source and when the utility goes out it will supply single phase 277 to selected lighting circuits from a battery stack.

I can't tell you much yet as I only noticed it in the prints and while it has arrived on site I have not unwrapped it to check it out.

Best I can tell so far it is just a 'UPS" that is listed for emergency lighting and probably with a 'dirtier' output than say a Liebert UPS.
 
We are talking milliseconds or 1 second.To a computer its milliseconds to average lights 1 second is no big deal.I am backed up to the milliseconds on computer but lights could easily be 5 seconds.All has to do with conditions and needs
 
5 seconds could make a big difference for HID lights, right? But I guess HID wouldn't usually be used for emergency lights.
 
I have few HID's outside that will be on emergency. Does milliseconds makes a different or I have to provide quartz restrike lamp? thanks
 
Looking at their catalog, Lithonia sells inverters with 3 transfer times: 2ms, 20ms, and 50ms.

The ones with 20ms and 50ms say they are for fluorescent or incandescent.

The ones with 2ms say for fluorescent, incandescent, or HID.

Steve
 
It really depends, we have installed a double conversion UPS for the emergency lighting in a Postal distribution facility. The only real difference is the batteries are sized to handle the full load for 90 minutes minimum. Also we are feeding H.I.D. lights so they do not want to see an outage.

-Ed
 
iwire said:
Ed, just curious if that double conversion unit was listed for the use as required by Article 700?
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Bob:
700 doesn't actually require the equipment to be "listed" for emergency systems. It requires it to be "approved". So the AHJ is the only one that can say if a regular UPS is suitable. (But a listing would probably make a double conversion unit more universally accepted).
 
Steve as always the NEC throws a curve, while 700.3 only requires that all equipment be approved 700.6 requires transfer equipment to be identified for the use along with being approved.

IMO a UPS contains the transfer equipment.


700.6 Transfer Equipment.
(A) General. Transfer equipment, including automatic transfer switches, shall be automatic, identified for emergency use, and approved by the authority having jurisdiction. Transfer equipment shall be designed and installed to prevent the inadvertent interconnection of normal and emergency sources of supply in any operation of the transfer equipment. Transfer equipment and electric power production systems installed to permit operation in parallel with the normal source shall meet the requirements of Article 705.
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I doubt a standard UPS is identified for emergency use.

Bob
 
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