Can one use a UPS to support darkroom equipment from voltage irregulations and loss of power?
UPS for darkroom equipment?
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If you get a big enough one I can't see why not.
The one I was looking at is this one:
http://www.frontierpc.com/ProductDe...328750&scrcode=cii_9927774&cpncode=11-1957532
But I wasn't thinking about using it in the darkroom.
You'll have to figure out how much power you need and for how long.
The one I was looking at is this one:
http://www.frontierpc.com/ProductDe...328750&scrcode=cii_9927774&cpncode=11-1957532
But I wasn't thinking about using it in the darkroom.
You'll have to figure out how much power you need and for how long.
OP
OP
I have an APC of 1500VA, that is 980Watts of power which can power my whole computer equipment for half an hour (about 480Watts in use). The thing is that with a computer, one only needs to save the working file and shutdown but a proccess in the darkroom may not be able to be interrupted for some time, like film developing in my Jobo CPP-2.
My Kaiser enlarger and RH Analyser Pro won't probably need much of power but I am afraid the Jobo would. I will have to do some research.
My Kaiser enlarger and RH Analyser Pro won't probably need much of power but I am afraid the Jobo would. I will have to do some research.
Some of the models can take add on batteries so you can have all the time you want. But the price goes up with each battery.
How much of a problem is your power? If it's a serious issue I think I'd build a 12v battery bank feeding a sine wave inverter. The cost will depend on how big an inverter you need. The advantage is 12v batteries are fairly common so the batteries won't cost an arm and a leg.
How much of a problem is your power? If it's a serious issue I think I'd build a 12v battery bank feeding a sine wave inverter. The cost will depend on how big an inverter you need. The advantage is 12v batteries are fairly common so the batteries won't cost an arm and a leg.
OP
OP
I am not an electrician so I doubt I could build a battery bank like you would Nick. But one can get a 1000VA (640W) UPS for about 200 euros.
It's not that complicated to cable together a battery and an inverter. If you can change a car battery it's not much different.
But the cost will end up being more then 200 Euros. Doesn't make sense unless your power goes out for long periods of time.
Where are you getting the UPS for 200 Euros? I spent some time last month checking UPS prices in Europe and the prices I could find were all much more expensive then the North American prices for the same models.
But the cost will end up being more then 200 Euros. Doesn't make sense unless your power goes out for long periods of time.
Where are you getting the UPS for 200 Euros? I spent some time last month checking UPS prices in Europe and the prices I could find were all much more expensive then the North American prices for the same models.
OP
OP
Well, I can't change a car battery, nor know anything technical about cars as I rarely make use of one.
But anyhow, one of the major computer chains of Greece has these prices:
- ACCUPOWER BL-1400 1400VA 169.00
- APC LINE INTERACTIVE 1000VA BR1000I 295.00
and some smaller ones which cost less than 100.
All are Line Interactive types.
I was just wondering if the work the same way with darkroom equipment as with a computer. Logically, they should (minus the software control), but just wondering.
I will give it a test with the UPS I have for the computer.
But anyhow, one of the major computer chains of Greece has these prices:
- ACCUPOWER BL-1400 1400VA 169.00
- APC LINE INTERACTIVE 1000VA BR1000I 295.00
and some smaller ones which cost less than 100.
All are Line Interactive types.
I was just wondering if the work the same way with darkroom equipment as with a computer. Logically, they should (minus the software control), but just wondering.
I will give it a test with the UPS I have for the computer.
Ari,
The CPP-2 has a power draw of 480 W when tempering - ie with the heater on. It will draw about 80 W for just the motor, because the heater is a 400 W unit. So insulate the tank if you are working in ambient temperatures well below the developer temperature. If you have passed the development stage, just turn the thermostat down and the heater won't come on. The UPS needs to be able to handle the full connected load, even if the load will be much reduced when the UPS is providing the power.
The APC BR1000I has a stated capacity of 54 minutes at 100 W; 27 minutes at 200 W; 17 minutes at 300 W; 11 minutes at 400 W; 8 minutes at 500 W and 6 minutes at 600 W. So the less power you draw the more total energy you get from it.
I guess that you are doing just B&W you chromophobe. Voltage stabilisers are common for colour enlargers, by the way. If you are working somewhere that has serious mains voltage fluctuations the stabilising effect of a UPS could be useful for B&W as well.
If you are anticipating long-term power loss, then get a little generator as well, so you can let the UPS do its uninterruptible thing, then start up the genny and plug the UPS and your lights etc into the genny. All you would need the UPS for is the short time it would take to find the generator, attempt to start it, take it to a mechanic, wait for spares to arrive, fill it with gas and plug the UPS in.
Best,
Helen
The CPP-2 has a power draw of 480 W when tempering - ie with the heater on. It will draw about 80 W for just the motor, because the heater is a 400 W unit. So insulate the tank if you are working in ambient temperatures well below the developer temperature. If you have passed the development stage, just turn the thermostat down and the heater won't come on. The UPS needs to be able to handle the full connected load, even if the load will be much reduced when the UPS is providing the power.
The APC BR1000I has a stated capacity of 54 minutes at 100 W; 27 minutes at 200 W; 17 minutes at 300 W; 11 minutes at 400 W; 8 minutes at 500 W and 6 minutes at 600 W. So the less power you draw the more total energy you get from it.
I guess that you are doing just B&W you chromophobe. Voltage stabilisers are common for colour enlargers, by the way. If you are working somewhere that has serious mains voltage fluctuations the stabilising effect of a UPS could be useful for B&W as well.
If you are anticipating long-term power loss, then get a little generator as well, so you can let the UPS do its uninterruptible thing, then start up the genny and plug the UPS and your lights etc into the genny. All you would need the UPS for is the short time it would take to find the generator, attempt to start it, take it to a mechanic, wait for spares to arrive, fill it with gas and plug the UPS in.
Best,
Helen
A UPS won't handle voltage irregulations (for this you need a voltage stabilizer, the most common being a magnetic saturation stabiliser (Sola is a common brand in the U.S.).arigram said:
A UPS will, however, be able to provide backup power, for instance, to keep a film processor running--- a very good idea. The current they produce, however, tends to be not very good (a very crude square wave) so you might need to see about the timing circuits of you machines to make sure they are compatable.
One can, of course, get very good power sources. In a project we've been tinking with portable computer controlled inverter systems to provide power. They are available in 12v and 24v systems. We have one running now in Crete in prototype. A big generator, a big motor, a ton of batteries, some inverters and eventually some tracking solar panels and... just the stuff for a lab in the middle of nowhere!
Ed,
"A UPS won't handle voltage irregulations"
I believe that the APC UPS that Ari mentioned has auto voltage regulation. Isn't that the case for most true UPS's, as opposed to mere 'rapid acting standby power supplies'?
Best,
Helen
"A UPS won't handle voltage irregulations"
I believe that the APC UPS that Ari mentioned has auto voltage regulation. Isn't that the case for most true UPS's, as opposed to mere 'rapid acting standby power supplies'?
Best,
Helen
The triplite I posted provides regulation for both over and under voltage.
"Tripp Lite's OMNIVSINT1500XL line interactive UPS system offers voltage regulation, surge suppression and long lasting, expandable battery"
Not the cheapest model but not the most expensive either.
"Tripp Lite's OMNIVSINT1500XL line interactive UPS system offers voltage regulation, surge suppression and long lasting, expandable battery"
Not the cheapest model but not the most expensive either.
Nope. They'll handle drop-outs (black and brown outs) and spikes. Computers have switched power supplies so don't really need anything more sophisticated. Its, however, ill-suited to enlargers and might be inadaquate for developing machines (depends upon their design). Timing circuits might need line synchronization and some devices might need more regulated and/or cleaner power. These glorified batteries might be relatively inexpensive but they don't often cut the mustard...Helen B said:
Nick Zentena said:
Look at the quality of the power produced and ask them what the regulation range is! Some of the best ones might be within +/-5% (that's a 10% span) but that is in many darkroom applications insufficient.
By contrast:
http://www.solaheviduty.com/products/powerconditioning/Index.htm
Its, of course, even more complex.. As I've mentioned.. some machines have synchronous motors and depend upon the line frequency to keep timings.
I may also add.. one should look at the connection between illumination and voltage to understand that 10% voltage range does not mean 5% less or more light but signifcantly larger differences.edz said:
A UPS is a device that provides a backup supply in the event the normal commercial supply is interrupted. The come in various configurations - in most instances, the alternating current mains supply is rectified to make DC, and then inverted to make AC. Some kind of energy storage device is then floated on the DC link. In most smaller applications, this is a battery, but there are UPS systems that use flywheels for energy storage. But the net effect is that the output is independent of the input.
The fact that the UPS must invert the DC link voltage to make AC means that most have the abilty to provide regulation of the output, and the fact that there is a DC link means that the output is relatively independent of variations in voltage magnitude or frequency on the input.
So in that sense, UPS systems do provide enhanced power quality (regulation) for the load they serve. But they also have an inherent regulation characteristic - that is, while the output voltage of a UPS may be totally independent of the input voltage, the voltage output of a UPS may vary as the load on the UPS varies.
True UPS systems are pretty expensive. Seems to me that it would be helpful to think carefully about what a darkroom application really requires. Voltage regulation has to be at the top of the list. A variation of 10% in voltage results in a variation in output from the lamp in an enlarger by nearly 20% (Light output is approximately proportional to the square of the lamp voltage.)
Another possibility is frequency control. Someone mentioned the concern that timers could be erroneous if there are excursions in frequency. I agree, but would point out that timing accuracy that if the timer is based on a motor, then timing error is about proportional to frequency error. As a practical matter, a frequency error of 1% is probably about the worst you will encounter in most instances. I have seen errors that are greater than that (in my career as a power engineer) but in those cases, the consequence of frequency errors on other equipment meant that those systems were isolated and reserved for very special loads. So as a practical matter, frequency correction is not likely to be a real need.
If regulation is at the top of the list, I would place the ability to ride through a supply interruption at the bottom of my list. At least where I live, the frequency of interruptions is fairly low - perhaps 5-6 events per year. Frankly, I've had a darkroom for about 28 years, and I don't recall a single instance when we had an interruption while I was printing.
So if what is needed is voltage regulation, I think there are much less expensive solutions than a UPS. Someone mentioned ferroresonant transformers - they work very well as long as the input voltage fluctuation is not ridiculously extreme.
The fact that the UPS must invert the DC link voltage to make AC means that most have the abilty to provide regulation of the output, and the fact that there is a DC link means that the output is relatively independent of variations in voltage magnitude or frequency on the input.
So in that sense, UPS systems do provide enhanced power quality (regulation) for the load they serve. But they also have an inherent regulation characteristic - that is, while the output voltage of a UPS may be totally independent of the input voltage, the voltage output of a UPS may vary as the load on the UPS varies.
True UPS systems are pretty expensive. Seems to me that it would be helpful to think carefully about what a darkroom application really requires. Voltage regulation has to be at the top of the list. A variation of 10% in voltage results in a variation in output from the lamp in an enlarger by nearly 20% (Light output is approximately proportional to the square of the lamp voltage.)
Another possibility is frequency control. Someone mentioned the concern that timers could be erroneous if there are excursions in frequency. I agree, but would point out that timing accuracy that if the timer is based on a motor, then timing error is about proportional to frequency error. As a practical matter, a frequency error of 1% is probably about the worst you will encounter in most instances. I have seen errors that are greater than that (in my career as a power engineer) but in those cases, the consequence of frequency errors on other equipment meant that those systems were isolated and reserved for very special loads. So as a practical matter, frequency correction is not likely to be a real need.
If regulation is at the top of the list, I would place the ability to ride through a supply interruption at the bottom of my list. At least where I live, the frequency of interruptions is fairly low - perhaps 5-6 events per year. Frankly, I've had a darkroom for about 28 years, and I don't recall a single instance when we had an interruption while I was printing.
So if what is needed is voltage regulation, I think there are much less expensive solutions than a UPS. Someone mentioned ferroresonant transformers - they work very well as long as the input voltage fluctuation is not ridiculously extreme.
Ed,
I agree that +/-5% on voltage would not be adequate for colour, but I think that Ari only does B&W. That +/-5% is for a +/-28%, or thereabouts, input voltage range isn't it? As Ed says, that +/-5% is at the upper end of the range for low-cost computer UPS's - others may only achieve +/-10% even with the inverter permanently connected. The simple CPP-2 he is intending to supply does not have a timer and his RH Analyser Pro accepts 200 to 250 V. It's a matter of paying your money and taking your choice.
But Ed is right: Ari, if you have the money, follow Ed's advice and get a truly voltage stabilized UPS.
I had the impression that Ari is concerned about loss of power.
Best,
Helen
I agree that +/-5% on voltage would not be adequate for colour, but I think that Ari only does B&W. That +/-5% is for a +/-28%, or thereabouts, input voltage range isn't it? As Ed says, that +/-5% is at the upper end of the range for low-cost computer UPS's - others may only achieve +/-10% even with the inverter permanently connected. The simple CPP-2 he is intending to supply does not have a timer and his RH Analyser Pro accepts 200 to 250 V. It's a matter of paying your money and taking your choice.
But Ed is right: Ari, if you have the money, follow Ed's advice and get a truly voltage stabilized UPS.
I had the impression that Ari is concerned about loss of power.
Best,
Helen
OP
OP
Thank you Ed, Helen and Mono, your posts have been very illuminating if in the end made be a bit more confused!
As Helen deducted (possibly from my sig or photos
) I do only BW.
I use a Kaiser enlarger which goes up to 6x7cm and is fitted with a Multigrade head.
The head uses a special power suppy which is a power regulator in itself (Kaiser makes two psu's one been the simple, the other the regulator) and so stabilising of the power that leads to the enlarger is not needed.
Printing is not so much of a concern as the worst that can happen when you lose power is to lose a piece of paper, but I am worried about the CPP-2 during film development as I use 2500 type tanks fitted with the cog wheel for the lift and so are not made for hand developing.
What Helen writes about the power needs of the CPP-2 is very helpfull.
I can buy a cheap UPS to atleast power the motor as the bath temperature is easy to handle as I use an airconditioner in the small darkroom so the ambient temperature is stable. Plus I do BW where the temperature is not a big deal, atleast compared to color.
Thank you all again.
As Helen deducted (possibly from my sig or photos
) I do only BW.I use a Kaiser enlarger which goes up to 6x7cm and is fitted with a Multigrade head.
The head uses a special power suppy which is a power regulator in itself (Kaiser makes two psu's one been the simple, the other the regulator) and so stabilising of the power that leads to the enlarger is not needed.
Printing is not so much of a concern as the worst that can happen when you lose power is to lose a piece of paper, but I am worried about the CPP-2 during film development as I use 2500 type tanks fitted with the cog wheel for the lift and so are not made for hand developing.
What Helen writes about the power needs of the CPP-2 is very helpfull.
I can buy a cheap UPS to atleast power the motor as the bath temperature is easy to handle as I use an airconditioner in the small darkroom so the ambient temperature is stable. Plus I do BW where the temperature is not a big deal, atleast compared to color.
Thank you all again.
I use an APC UPC, (the 1500 model i guess) and it works great with my Jobo. I use it in case of a blackout while processing. As for the regulation aspect I was always under the impression that the source supplying continuous power to my Jobo was the battery in the UPC which was simultaneously being charged. My only big concern is that if my darkroom floods the UPC might present a serious danger of electrical shock.
In all the APC UPS models I have looked at they only switch to battery after the voltage gets out of the acceptable range (settable on many). If the voltage is within range they simply pass line voltage through, so there is no regulation.
Also since they use lead acid batteries you really shouldn't run them down below 80% charge or you will significantly shorten your battery life. So buy one with a larger capacity (run time) than you need and don't abuse the battery.
Ari, for black and white as you are I would simply get the roller base, a funnel with a short length of tube and be done with it. Since your Jobo is not automated you will be standing nearby when the power fails and it should only take a few seconds to start hand rolling. Save the money for paper.
Also since they use lead acid batteries you really shouldn't run them down below 80% charge or you will significantly shorten your battery life. So buy one with a larger capacity (run time) than you need and don't abuse the battery.
Ari, for black and white as you are I would simply get the roller base, a funnel with a short length of tube and be done with it. Since your Jobo is not automated you will be standing nearby when the power fails and it should only take a few seconds to start hand rolling. Save the money for paper.
L Gebhardt said:
Then how do they achieve the voltage regulation they claim? APC use more than one type of system:
standby UPS: as you described, switches from line to battery on power failure, very efficient;
line interactive UPS: inverter always connected but not providing power while mains is present, incoming voltage regulated by tap-changing transformer, very efficient (the type Ari was looking at);
standby ferro UPS: saturating transformer normally connected to mains, switches to power from inverter on power failure (ie inverter output goes to ferro);
double conversion on-line UPS: inverter always provides the output power, good but wasteful (the type described by monophoto);
delta conversion on-line UPS: a variant of the double conversion design, the inverter is always on, but is augmented by power from the mains via the delta transformer, less wasteful than double-conversion.
As you see, they include standby power supplies as UPS's.
Best,
Helen
You're right Helen, APC does make some that claim to do true voltage regulation. It even appears my newest one does this as well. Now I will have to check how close it regulates and to what voltage.
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