UPS and iso transformer

[LX3]

One for you power gurus...

I'm upgrading the power system for my fly-pack rig. So this has to be portable enough to carry in and out of venues... often single-handed.

There are various online, dual-conversion UPSs I'm looking at.

But, concerning iso transformers, what do you think?...

a) UPS fed from the iso transformer
b) Iso transformer placed AFTER the UPS

(have seen both a and b recommended)

or

c) Don't bother with an iso transformer at all

It's hard to ascertain what these UPS do with the neutral supply line (might pass it straight thru? Or not?), so it's not clear how much benefit there'll be to having an iso transformer. But definitely a major weight penalty... UPS likely to be about 20kg, transformer adds another 15...

And bearing in mind nearly every venue in London involves at least two flights of stairs ...

Any thoughts?

[Remoteness]

Click on the POWER and UPS tags at the bottom of the forums main page...

There are plenty of threads about this subject.

[rufus13]

Instead of worrying about how awful the venue power is and bringing 80 pounds of isolation/regulating transformers and/or a battery UPS, build a battery pack that will do what you need with a 50% reserve capacity.

Then, like someone coming in with a Nagra, your only cabling is microphone ties. Speed and simplicity of set up will let you help someone else or get a snack before the show. Recharge back at the batcave while editing.

Cheers.

[LX3]

Originally Posted by Remoteness

Click on the POWER and UPS tags at the bottom of the forums main page...

There are plenty of threads about this subject.

On the topic of UPS's and transformers maybe, but not really addressing this subject... apart from two brief and contradictory recommendations. If I could have found an answer in older posts, or anywhere on the web for that matter, I wouldn't have asked the question.

Guess I'll do my thing and see what happens. I'm not noticing any audio problems with my current UPS, although I can't compare it with balanced power, so who knows. I suspect size and weight considerations will decide it. Is anyone here carrying 1.5kVA or more of UPS and iso transformer up and down flights of stairs?

It's not an insignificant project (UPS, distro, breakers, metering, flightcase), so I'd like to get this right, rather than build it, and then have to start over again.

(I forgot to mention, I need about 700W to keep the critical parts of the rig going... 10 minutes of that would be more than enough to shut things down, or at least establish if there's any chance of getting it back soon. So 1.5kVA would be about right.)

[gareth.h.rees]

Hi Paul.

Did you ever get an answer to this?

Wondering whether I should get a power conditioner on top of a UPS. I think it may be a good idea as I'll probably be getting an "APC Smart" series one... can't really afford much else!

ETA systems ones seem to be reasonably priced over here...

Cheers
Gareth

[Thomas W. Bethe]

We use a APC UPS into a TOPAZ Ultra Isolator transformer and it works great. It is built into a flight case with wheels and is all mounted on an aluminum plate with handles so it can be removed from the case and set on the floor. It works well and gives us about an hour's worth of run time if the power goes down.

[gareth.h.rees]

Cool! Good to know

Do you feel you need to run the isolator after the UPS though, or would you be happy running solely on the UPS?

Cheers
Gareth

[Thomas W. Bethe]

I would be happy with just the UPS but the ultra isolation of the TOPAZ it nice to have especially in some of the venues we do where there are lots of TRIAC dimmers.

[LX3]

Hi Gareth. I deferred the whole situation. Bought myself a new online UPS in early 2008 and cased it up. It's working great without an iso transformer and the plus side is I can pick it up with one hand . But I can see myself needing two separate UPS units in the near future, so I'm hoping to build another more sophisticated power system later this year.

[tenor39]

I would go with a true sine-wave UPS feeding a balanced power unit. This way you get noise rejection after the UPS, which is a good thing in my book. An iso-trans will only do so much, as there will be leakage around it through the ground if the secondary is still connected as a hot/neutral, with the Gnd and N being tied together.