October 26, 2010

240v 208v Challenges and magic Buck Boost transformers

I tend to answer a lot of questions about High Voltage systems (here, here, here) about its effects on UPS units.  

Today, we had a customer that wanted 240v for his equipment and another customer that wanted to use his 5000va 208v UPS in his 240v building.

Both challenges can be solved with Buck Boost transformers.  These affordable transformers step up and down voltage in a small frame by magic.

The customer that wanted 240volt for his equipment, bought one to plug in his wall and then plugged the 240volt UPS into it.  Then the UPS output was 240volt as he wanted.(Type 3u)

The customer that had a 208v UPS, but had 240v building power, plugged in the magic unit (Type 5d) and reduced the voltage to the UPS and lived happily ever after.

We sell 4 common configurations, all are Plug & Play easy, and are sized to the UPS you are using.  Notice, these units can only tweek the voltage, they are not full blown Step down 208v to 120v or Isolation transformers.  We have those as well.

Buying Guide for 7-10kva UPS units

When you want a large UPS, there 3 important specs to consider
  1. Is this for a single piece of equipment/panel? (or is for multiple loads)
  2. Are you prepared to hard wire this into your electrical system?
  3. Do you expect to grow and want an expandable solution?
1) If this large unit is to replace several small units, it might not be that great a deal to combine them.  One 10kva unit costs way more than two 5kva units.  ($1900 v $2500).   

2) The standard 30amp L630 outlet can only provide about 6000va of power.  Therefore if you want to use these larger UPS units, you need to have a new 50amp circuit hardwired or 50amp outlet  (both big bucks).   Many people have ordered 7,8 and 10k systems with a 30amp input plugs, essentially getting a 5000va for a 10,000va price.  Bottomline, invest in your electrical system if you need these units. 

3) One of the worst calls i get is from people that have 10kva systems and want to upgrade.   They have probably already invested about $4000 in a 10kva ups system (more if it was new), with the unit, some battery packs and the 50amp electrical.  Once you goto the next step of 16kva, the unit, battery packs, and electrical system becomes obsolete.  Plus the 16kva is an expensive step up anyway.   Bottomline, if your panel needs 10kva now, consider using a Symmetra format.  Their components are modular and can grow with you, up to to that 16kva size.

October 25, 2010

When you need Online UPSes

I have noticed a uptick on requests for Online or double conversion UPSes.  So below is a quick primer on what it really means and why you probably dont need one

  • WHAT is it -  Online UPS is a UPS technology or approach to handling how the UPS acts during an event. Regular UPS technology (called line interactive) sense a loss in power and switch to battery power.  This switch happens in 5 milliseconds.  Online UPSes are essentially always using battery power to operate so they never "switch" power.  Further, while regular UPSes can take some "dirty" power before switching over to clean battery power, Online is always providing clean power.   According to Wikipedia Online UPSes main advantage is UPS is its ability to provide an electrical firewall between the incoming utility power and sensitive electronic equipment.  Bottomline, Online UPS are better, but are more expensive. ($439 v. $595)
  •   v. 

  • WHY you DON'T need it  - Almost everything electric is designed to work on our dirty electrical power grid. So if you just want your stuff to work, Online's super clean power really isnt needed.  Further, the 5ms switchover is more than fast enough to keep your equipment humming.  As for surge protection, both systems are pretty pathetic. Its best to get a panel mounted unit as I dont know if that "firewall" can really hold up to a doozy.
  • Why you MIGHT need it - If having a clean sine wave waveform is important, such as in instrumentation or equipment designed for the lab, then its worth it.  Also if you have a backup generator, its best to go with a Online UPS because you really need the firewall with the atrocious power those generators put out.
If you need one, my store has a page for them

October 24, 2010

Best Technical Blog Posts (de facto FAQs)

What are the Important Specs in comparing UPS units

This week a customer sent me a spec page for a UPS brand I had never heard of  (ProVar 5000, or something).  While spec pages have hundreds of features, there are 4 to concentrate on

UPS Technology  -  Today there a 2 types, Line Interactive or Online/Double Conversion.  Online provides the cleanest power and is generally a lot more money.  If the existing spec is Online, its only fair to compare a similar model.  But it is often over requested.

VA/Watts - These are the UPS's electrical capacity.  The VA is often part of the model number and headline spec.  The watts can be 90%, 80% or 70% of that value depending on the units Efficiency.  So, if someone asks for a high efficiency 2200va capacity unit, I will probably spec a 3000va, to get their desired watts just because upgrading to a high efficiency unit is more than upgrading the VA.

Voltage - Tthis is where the spec pages can get you in trouble.  120volt is simple, but higher voltages are much more complex.  There is big difference between Voltage Range and Nominal Voltage.  Ignore the Voltage Range on the spec. UPSes are pre-set to accept 208, 220, 230, and/or 240v.   A 208v system wont  work on 230v and vice versa.  Also, UPSes cant normally change the power.  If you want 230v output and have only 208v at your building, you can't buy a 230volt UPS.  Nearly every commercial building in the US has 208volt.  Rarely would you have 240 or anything else.   Look at my last post about how we have managed the different types

Plugs and Ports -  All input plugs can be changed to match your needs.  The backplate or output receptacles can generally be changed as needed.  So the only port that is important, is the XL or Extended Run port.  Nearly every unit (except those made by APC) has a port to add extra battery packs to to add runtime. Like the Online spec, its important to make sure customers know they are usually paying 10-25% more for this feature.

As for the remaining specs, most aren't critical and usually match among manufacturers.  Frequency, Crest factor, BTus, Environmental, Surge Protection, Wave form, are all about the same for a given UPS size and type.

Two other factors, physical size and runtime, usually can be handled once a particular model has been chosen.      Smaller units usually cost more, and runtime is completely dependent on battery size.  

October 13, 2010

Random APC Part of the month III

As I review an international brochure from APC, I notice some curious new APC UPSes that I have never seen.
This class of Online UPS is called the the Smart UPS RCs

They are just like the SURT line, but these are rated for "Harsh Environment"

They are a 4U rack tower, have about twice the runtime as the regular 3000va SURT300XLI unit,(393ig3) but are rated for upto 50C and down to -20C.  They also curiously have Dataline surge suppression, which is more a Back-UPS product feature.

Presenting the SRC3000XLI  ...

Its for sale at the Brazilian online store TechClube.. which sounds more like an 80s dance place.

October 7, 2010

Why is Powerware the best?

As I have mentioned before, Powerware makes the best UPSes today (2-10kva).

Many people have strong opinions about their brand, but here is my reasoning:

  • IBM units are rebranded Powerware units.  IBM customers pay a premium for the best servers and want the best UPS, IBM couldnt take APC's failures and down market line so changed in 2009.
  • Powerware ships Genesis/Yuasa High Rate batteries in their 9125 line, APC uses junky BB batts on the equivalent model which suggests Powerware doesnt cheapen its components and cares about quality, not always price
  • As electricians, Powerware was always spec'd and installed on new construction projects suggesting engineers respect the Powerware line.
  • Components on Powerware are heavy duty.  Screws, handles, boxes, etc are seem to be better made
So if thats the case, why are Powerware units cheaper on your site?  The simple fact is that APC has better brand recognition to my customers and your demand sets my prices. 

But those in the know, buy up my Powerware double conversion 3000va 2U PW9125 units and laugh at the thought of paying $200 more for APC's version.