Efficiency of Sola Constant Voltage Transformer?

[Mark & Mary Ann Weiss]

I can't seem to find a valid web site for Sola-HeviDuty, the manufacturer,
but I'm considering adding a model 23-23-220-8 CVS ahead of our UPS to clean
up the harmonics from our generator so that we can run the UPS on the 'high
sensitivity' mode without having it constantly switch to battery.

The only concern is how much this is going to add to our operating cost,
assuming 11-cents/kWh. What is the efficiency of these saturated-core
beasts? Back in the old days, we used to use them with automatic inspection
equipment, but no one was concerned about energy costs back then. We have a
network of computers here, pulling just nigh of 2kVa, running on a
similarly-rated APC UPS. How much energy is wasted by the 2kVa Sola
transformer?


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Steve Noll]

I can't seem to find a valid web site for Sola-HeviDuty, the manufacturer,
but I'm considering adding a model 23-23-220-8 CVS ahead of our UPS to clean
up the harmonics from our generator so that we can run the UPS on the 'high
sensitivity' mode without having it constantly switch to battery.

The only concern is how much this is going to add to our operating cost,
assuming 11-cents/kWh. What is the efficiency of these saturated-core
beasts? Back in the old days, we used to use them with automatic inspection
equipment, but no one was concerned about energy costs back then. We have a
network of computers here, pulling just nigh of 2kVa, running on a
similarly-rated APC UPS. How much energy is wasted by the 2kVa Sola
transformer?

Don't know why you weren't able to find this:
http://www.sola-hevi-duty.com/index.htm

Manual for the model you're interested in. The answer may be in here:
http://www.sola-hevi-duty.com/products/powerconditioning/PDFs/Manuals/CVSManual.pdf

They are still pretty inefficient. Don't think the technology has
changed since day one. But boy do they work good, especially the CVS
(1%) series!

Steve Noll | The Used Equipment Dealer Directory:
| http://www.big-list.com
| Peltier Information Directory:
| http://www.peltier-info.com

 

[NSM]

I can't seem to find a valid web site for Sola-HeviDuty, the manufacturer,
http://www.solaheviduty.com/

but I'm considering adding a model 23-23-220-8 CVS ahead of our UPS to clean
up the harmonics from our generator so that we can run the UPS on the 'high
sensitivity' mode without having it constantly switch to battery.

I wouldn't.

The only concern is how much this is going to add to our operating cost,
assuming 11-cents/kWh. What is the efficiency of these saturated-core
beasts? Back in the old days, we used to use them with automatic inspection
equipment, but no one was concerned about energy costs back then. We have a
network of computers here, pulling just nigh of 2kVa, running on a
similarly-rated APC UPS. How much energy is wasted by the 2kVa Sola
transformer?

I'd be more worried about the output waveform esp. during any power outage
situation. I'd certainly run the idea past the UPS maker first. I suggest
you get APC to re-engineer a solution for you.

N

 

[Mark & Mary Ann Weiss]

Don't know why you weren't able to find this:
http://www.sola-hevi-duty.com/index.htm

I did a Google search and it took me to a web site with an almost identical
name that wasn't Sola's web site. I hate those copycat domain names, trying
to steer legitimate business toward spam sites. Anyway...

Manual for the model you're interested in. The answer may be in here:
http://www.sola-hevi-duty.com/products/powerconditioning/PDFs/Manuals/CVSMan
ual.pdf

They are still pretty inefficient. Don't think the technology has
changed since day one. But boy do they work good, especially the CVS
(1%) series!

Thanks for this link. I think page 12 summed it up, by mentioning that the
input current will be 50% of the full load current, even if no load is
present. So that suggests that it's wise to get the right size CVS, not an
oversized one!


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Mark & Mary Ann Weiss]

manufacturer,

http://www.solaheviduty.com/

Google found me this link sola-heavy-duty.com which is a spam-infested mess
and NOT Sola's site. Thanks for the correct link.

I wouldn't.
......................

I'd be more worried about the output waveform esp. during any power outage
situation. I'd certainly run the idea past the UPS maker first. I suggest
you get APC to re-engineer a solution for you.

N

Too costly. I bought the UPS as a refurbished unit. I'm shopping for a used
CVS on Ebay. I have hundreds of dollars to spend on this, not $30,000+ for a
reengineered solution.

My testing has verified that our problem is not generator frequency, but
harmonics. The UPS sensitivity can be lowered, but then when it switched,
several computers on the network reboot. Only in the High sensitivity
position does the APC UPS switch fast enough to avoid rebooting computers on
the network. Although on the setting below High sensitivity, the UPS is
happy on generator power. Only problem is we have stuff rebooting when it
cuts over.
Hence, we must run in the high sensitivity mode of the UPS and clean up the
input power with the Sola CVS.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Bennett Price]

I'd be a little cautious about this. The nature of the load the xformer
is driving will effect how the xformer performs. I'd ask APC (and/or
check their FAQs) whether CVS might be a problem. I had a fluorescent
desk light that would not start when connected to a CVS - not the same
thing as a UPS but ....

 

[Mark & Mary Ann Weiss]

I'd be a little cautious about this. The nature of the load the xformer
is driving will effect how the xformer performs. I'd ask APC (and/or
check their FAQs) whether CVS might be a problem. I had a fluorescent
desk light that would not start when connected to a CVS - not the same
thing as a UPS but ....

My biggest concern is becoming one of whether this will vastly increase our
electric consumption. I read some documentation that suggests that a 2kVa
CVS will pull 1kVa at no load! They are most efficient at 100% load. So even
though this would be going in front of a 2.2kVa UPS, our load is about 10
amperes on that branch, so I chose to get a 1kVa Sola 23-25-210 model, used,
for $45, with the intent of loading it fully to maximize efficiency. Another
thing mentioned in the docs is heat. They are designed to run so that the
core is too hot to touch! That means more a/c load to cool the room. Lots of
things to consider.
But the used CVS is cheap enough so that if it doesn't give the results we
want, we haven't lost $1700 that a new one would have cost.
I'm very surprised that a desk lamp would not start. It must have had a high
inrush current. That IS a concern with the Sola, as they fold back, and one
PC power supply alone has a 80 ampere inrush current. Hopefully the CVS can
handle that short spike before the field collapses and recover
transparently. We'll see. The concern is more one of switching loads. But it
may not be sensible to shut off unused PCs on the network once the CVS is
installed, since the line current will be pretty much constant regardless of
load on the CVS.
Alternatively, we just modify all PC power supplies by adding a humungous DC
input cap after the bridge rectifier, to increase the holdout time long
enough so that we can use the "less" sensitive setting on the APC UPS, which
slows down switching from line to UPS. Several pieces of equipment need
modifying in this manner. A few seem to be okay with the momentary
interruption in power as the UPS switches to online mode. Ultimately it will
be an experiment.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Do Little2]

"Mark & Mary Ann Weiss" <[email protected]>
wrote in message

My biggest concern is becoming one of whether this will vastly increase
our electric consumption. I read some documentation that suggests that a 2kVa
CVS will pull 1kVa at no load! They are most efficient at 100% load. So
even though this would be going in front of a 2.2kVa UPS, our load is about 10
amperes on that branch, so I chose to get a 1kVa Sola 23-25-210 model,
used, for $45, with the intent of loading it fully to maximize efficiency.
Another thing mentioned in the docs is heat. They are designed to run so that the
core is too hot to touch! That means more a/c load to cool the room.

Besides the heat build up, keep in mind that they are noisy beasts and
you really do not want one sitting next to you in a quiet working area.
What maybe a little bit more efficient is a automatic-variable
transformer in your amp range. Those are also great as line spike
absorbers, etc.. and not as noisy, unless one set the auto-adjust to
sharply.

 

[Mark]

Yes,
saturated core transformers BUZZ and get hot, even under no load. They
are not nice things to have around.

Note 1 KVA is not necesserily = 1 kW. At no load a good deal of that
is reactive power but still enough true power to get the core hot.


Are you sure it is harmonics that are triggering your UPS?

Mark

 

[Jim Adney]

My testing has verified that our problem is not generator frequency, but
harmonics. The UPS sensitivity can be lowered, but then when it switched,
several computers on the network reboot. Only in the High sensitivity
position does the APC UPS switch fast enough to avoid rebooting computers on
the network. Although on the setting below High sensitivity, the UPS is
happy on generator power. Only problem is we have stuff rebooting when it
cuts over.

You may not like this solution, but:

I've never tried this, but how about just opening up each computer
power supply and replacing the input bridge filter capacitors to give
the power supply more "ride thru" time? You might also want to upgrade
the input rectifier diodes to survive the larger turn-on surge.

Doing this should allow you to run the UPS at a lower sensitivity
setting and still keep the PCs on line. Plus, I don't think it would
affect your efficiency at all.

Does this make sense, or am I missing something obvious?

Oops, I've read on down the thread and see that you've already
considered this option. I think the hardest part about it would be
finding new caps that fit in all the different PC power supplies. If
the PCs are all alike then this becomes pretty easy. I don't think you
really need to find caps more than 2x larger to make a pretty
significant difference.

-

 

[Mark & Mary Ann Weiss]

Besides the heat build up, keep in mind that they are noisy beasts and
you really do not want one sitting next to you in a quiet working area.
What maybe a little bit more efficient is a automatic-variable
transformer in your amp range. Those are also great as line spike
absorbers, etc.. and not as noisy, unless one set the auto-adjust to
sharply.

You mean like the TrippLite LC2400? I had one of those and all it did was
create a 'bounce' effect that resulted in the UPS starting up, shutting
down, causing the LC2400 to switch taps, which caused a spike that the UPS
thought was a line fault, triggering another cycle of UPS coming online, ad
infinatum. Plus the LC2400 injected so much trash back into the line that
other connected equipment on that branch got damaged.

It has to be a transformer, but no tap switching.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Mark & Mary Ann Weiss]

Are you sure it is harmonics that are triggering your UPS?

I have confirmed that it's not line frequency that's triggering it. So it
has to be harmonics, of which there are a lot. The waveform looks like a
squared-off ragged sine wave. I can lower the sensitivity, but then the PCs
reboot in the time it takes to transfer from line to UPS.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Mark & Mary Ann Weiss]

You may not like this solution, but:

I've never tried this, but how about just opening up each computer
power supply and replacing the input bridge filter capacitors to give
the power supply more "ride thru" time? You might also want to upgrade
the input rectifier diodes to survive the larger turn-on surge.

Doing this should allow you to run the UPS at a lower sensitivity
setting and still keep the PCs on line. Plus, I don't think it would
affect your efficiency at all.

Does this make sense, or am I missing something obvious?

Oops, I've read on down the thread and see that you've already
considered this option. I think the hardest part about it would be
finding new caps that fit in all the different PC power supplies. If
the PCs are all alike then this becomes pretty easy. I don't think you
really need to find caps more than 2x larger to make a pretty
significant difference.

It is likely that I will resort to this. I am also in the process of
replacing old, inefficient Antec PSUs with more efficient Seasonic PSUs that
are PF corrected. If that doesn't solve the holdover time, I may resort to
modifying each PSU. Most PSUs have 680uF/200V caps in the bridge circuit. If
I could find larger ones, or just tack some larger caps across it, that may
do the trick. However, I also must modify some musical instruments that are
resetting on this UPS. But that may be simpler. I think they use linear
PSUs. Schematics are harder to find as they are proprietary protected
property of the manufacturers.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Do Little2]

You mean like the TrippLite LC2400? I had one of those and all it did was
create a 'bounce' effect that resulted in the UPS starting up, shutting
down, causing the LC2400 to switch taps, which caused a spike that the UPS
thought was a line fault, triggering another cycle of UPS coming online, ad
infinatum. Plus the LC2400 injected so much trash back into the line that
other connected equipment on that branch got damaged.

I don't know about TrippLite's but one 35 amp unit has been in
constant use here for over 17 years without a hint of a problem.

It has to be a transformer, but no tap switching.

Okay, no sense looking up the manufacturer then.

You know that most computer PSU have a bridge rectifier directly
on the AC input, so I am not even sure what all the fuzz is all about.

A good AC filter block is all you really need in front of a UPS, that
is, if the AC voltage is within the UPS range.

 

[Mark]

you may find that if you switch to power factor correct power supplies,
the harmonics go away.

Question...

Does the generator create harmonics when feeding a resistive load or
does the generator create harmonics only when feeding non power factor
corrected loads.

The bridge rectifier capcitor inputs to many power supplies, conduct
and load the generator only during the peak, and this can create the
clipped waveform and harmonics that you describe. PF corrected
supplies will (should) not do this.

Mark

 

[David C. Partridge]

Daft question - why not use an on-line UPS?

Dave

 

[Mark & Mary Ann Weiss]

I don't know about TrippLite's but one 35 amp unit has been in
constant use here for over 17 years without a hint of a problem.

I'm sure that they have their appropriate uses, but one of them is NOT in
front of a UPS.

Okay, no sense looking up the manufacturer then.

You know that most computer PSU have a bridge rectifier directly
on the AC input, so I am not even sure what all the fuzz is all about.

A good AC filter block is all you really need in front of a UPS, that
is, if the AC voltage is within the UPS range.

The fuzz is from the generator. At default (high) sensitivity, the UPS
triggers a transfer to battery when it sees the hash from the generator. I
tried throwing some oil filled motor start caps across the line, but they
had no effect. Something more radical, such as a CVS with harmonic
neutralization is needed here.
What sort of AC filter did you have in mind? The generator output looks like
a badly clipped sinewave with jagged steps. Cleaning that up will take MAJOR
filtering.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Mark & Mary Ann Weiss]

you may find that if you switch to power factor correct power supplies,
the harmonics go away.

These harmonics are from the generator, not the load. At the time, we had
about 5kW of air conditioning load on the genset, but the waveform is pretty
consistent with various loads.

Question...

Does the generator create harmonics when feeding a resistive load or
does the generator create harmonics only when feeding non power factor
corrected loads.

It's just dirty in general. Think of a motor with brushes. The field coil
has brushes. That probably has a lot to due with the way the ac power looks.

The bridge rectifier capcitor inputs to many power supplies, conduct
and load the generator only during the peak, and this can create the
clipped waveform and harmonics that you describe. PF corrected
supplies will (should) not do this.

Mark

Yes, but this would have an infinitessimal effect.
I'm going with the higher capacity supplies that are PF-corrected not only
to reduce operating costs, but because it will probably have a longer
holdout. I still have to come up with a strategy for the Kurzweil PC2R,
which uses a combination external 14VAC/9VDC transformer and who-knows-what
for rectification and smoothing inside the unit itself.
I'm also going to experiment with a used Sola 1kVa CVS that I bought on eBay
for $45 this week.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Mark & Mary Ann Weiss]

Daft question - why not use an on-line UPS?

Dave

Cost, heat, cost of operation. We have an offline UPS at present that we
just invested in, replacing a 15+ year old ferro UPS.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

 

[Do Little2]

"Mark & Mary Ann Weiss" <[email protected]>
wrote in message [snip]

What sort of AC filter did you have in mind?

(Google for "active tracking filters")
http://www.google.ca/search?hl=en&q="active+tracking+filters"&meta=

The generator output looks like
a badly clipped sinewave with jagged steps.
Cleaning that up will take MAJOR filtering.

Always try to get rid of the interference right at the source.
So buy a heavy duty Sola CVT for the generator so it can
handle the current. The rest is all patch-work. There is no
free lunch while doing business, less one receives a forgivable
government grant, everything cost money. So you'll have to
throw some real money into it or learn to live with the situation
the way it is....