[SML] Motors on UPSs

[Dale Farmer]

Probably too late at this stage in the design, but if you used hydraulic 
cylinders instead of electric motors, you could have the brute power 
stored in hydraulic accumulators. Then all you need to put on the UPS is 
the control stuff, which would be COTS, instead of some mongo UPS you 
have to create.   Lot of amusement park rides use hydraulic accumulators 
so they don't need huge pumps to satisfy momentary peak demands of the 
ride, just a smaller pump that runs steadily all day long.

Hmmm...  One large UPS system I saw described in a magazine one time had 
a motor/generator set with a big flywheel and a pneumatic motor.  The 
flywheel smooths out the energy and provides the couple of seconds of 
carryover.   The pneumatic motor is hooked into a large bank of 
compressed air tanks, and the control system opens up the air valve as 
needed.  The compressed air kept the data-center online long enough for 
the backup generator to start up and settle out.  A separate air 
compressor recharges the air bank when the power comes back.   No idea 
who makes it.

   Good luck with the job.

   --Dale

On 1/15/2015 11:26 PM, Michael Sauder via Stagecraft wrote:
> On Thu, Jan 15, 2015 at 10:41 PM, Jerry Durand via Stagecraft 
> <stagecraft at theatrical.net <mailto:stagecraft at theatrical.net>> wrote:
>
>     Just a comment on the auto-taps.  I'm sure your electricians know
>     about
>     it, but just in case it's worth noting.  When you get a brownout
>     and the
>     transformer switches, your Amp draw will go UP by about the same
>     percentage as the brownout goes DOWN.  Not a problem unless you're
>     running close to full capacity and you have a deep brownout.
>
>
> Yep. I'm a dodgy electrician, but I still knew this much, and told as 
> much in my email to the producers tonight.
>
> /"I'm sure your electricians know about it, but just in case it's 
> worth noting."/
> /
> /
> I've learned not to assume a single thing. My emails tend to be 
> lengthy and detailed (which sometimes means people don't read them 
> carefully), but at least then I can't be blamed for not throughly 
> explaining something.
> /
> /
> Despite this, the electrical drawings I received earlier this week 
> were full of errors, some major. How much of this was incompetence, 
> how much was lost in international translation, and how much of it was 
> my own inexperience, I don't know...
>
> A side point I'm really curious about: When you read "220V 3 phase" do 
> you folks read that as "Each leg is 127V, any two of which give you 
> 220V" or do you read it as "Each leg is 220V, any two of which give 
> you 380V"? (Convert to U.S. figures as needed)
>
> As you might guess, we need one interpretation (127V per leg) while 
> the drawings specced another (220V per leg). Which meant that a 
> required 50kVA transformer was not in the drawings, or budget.
>
> Michael S.
>
>
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