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Old Jul 22, 2012, 10:06 PM   #51
ScottishCaptain
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Quote:
You asked for it....
I don't think that's what the article is trying to say.

Figure 1 is simply detailing the internal waveform coming off a square wave inverter. It's totally above the centre axis of the graph, so there's no inversion going on there- that would have to be handled by a separate circuit down the line. And there's no way that is what they're blaring out of the back of the PSU because I'm not aware of -any- equipment, APFC or not- that would survive being hit by that kind of signal. Also, I'm not sure where you're getting 400V from because the graph is totally unlabelled.

I don't mean to question you here, but do you have any other evidence of this? I've discussed this matter at length with both Apple and APC over the span of approximately a month, and I was told exactly what that paper describes in Figure 2- that a stepped sine wave can introduce a "dead zone", and if that zone happens to be long enough an APFC power supply will simply shut off. Not once was I told or warned that a stepped sine wave could actually damage such equipment.

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Old Jul 22, 2012, 10:15 PM   #52
nanofrog
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Quote:
Originally Posted by ScottishCaptain View Post
I don't think that's what the article is trying to say.

Figure 1 is simply detailing the internal waveform coming off a square wave inverter. It's totally above the centre axis of the graph, so there's no inversion going on there- that would have to be handled by a separate circuit down the line. And there's no way that is what they're blaring out of the back of the PSU because I'm not aware of -any- equipment, APFC or not- that would survive being hit by that kind of signal. Also, I'm not sure where you're getting 400V from because the graph is totally unlabeled.

I don't mean to question you here, but do you have any other evidence of this? I've discussed this matter at length with both Apple and APC over the span of approximately a month, and I was told exactly what that paper describes in Figure 2- that a stepped sine wave can introduce a "dead zone", and if that zone happens to be long enough an APFC power supply will simply shut off. Not once was I told or warned that a stepped sine wave could actually damage such equipment.

-SC
The article itself is just a basic description of the types of inverters.

My point, has to do with how the circuits are actually made, so it focuses on the voltages (peak step value output of the UPS >> than the peak input voltage of an APFC PSU). This isn't opinion, it's physics.

Over-volt a capacitor, and it's going to die. Potentially explosively, if the voltage is high enough (there are youtube videos of this).

Now why I focused on Figure 1 rather than Figure 2 (which is what causes the OFF condition on some APFC PSU's due to zero - potential, aka dead time), is that most of the Stepped Inverter types output is that of Figure 1 (3 steps).

PWM based inverters increase the number of steps, so the peak output voltage does not exceed the input voltage of an APFC PSU design. And this is how CyberPower got around this issue (solves the issue, yet still cheaper to produce than traditional Pure Sine wave inverters).
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Old Jul 22, 2012, 10:17 PM   #53
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Old Jul 22, 2012, 10:28 PM   #54
ScottishCaptain
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Quote:
Originally Posted by nanofrog View Post
The article itself is just a basic description of the types of inverters.

My point, has to do with how the circuits are actually made, so it focuses on the voltages (peak step value output of the UPS >> than the peak input voltage of an APFC PSU). This isn't opinion, it's physics.

Over-volt a capacitor, and it's going to die. Potentially explosively, if the voltage is high enough (there are youtube videos of this).

Now why I focused on Figure 1 rather than Figure 2 (which is what causes the OFF condition on some APFC PSU's due to zero - potential, aka dead time), is that most of the Stepped Inverter types output is that of Figure 1 (3 steps).

PWM based inverters increase the number of steps, so the peak output voltage does not exceed the input voltage of an APFC PSU design. And this is how CyberPower got around this issue (solves the issue, yet still cheaper to produce than traditional Pure Sine wave inverters).
http://www.youtube.com/watch?v=3dEJIzwa_3E

That's the closest thing I could come to finding something like this. Skip past midway when he engages the UPS, and much to my horror- that thing is throwing off a square wave- but there doesn't appear to be any significant over-voltage (if any) at all. The best I can make out is that the leading ledge of the square wave is slightly higher then that of the A/C sine wave, but not by much.

I know capacitors can leak and explode, in a former life I specialized in PLC and HMI systems. And I'm not questioning the fact that a square wave could potentially be a really, really bad thing for -any- power supply that expects a sine wave, I'm just on the fence about the fact that it will actually cause irreparable damage.

Again, I sure as **** would NEVER run a Mac Pro off a Back-UPS for the reasons shown in the video above. I would recommend a pure sine wave UPS for anything, irregardless of the cost simply on the principal of operation.

I've just never heard of a square wave inverter *damaging* a PSU.

-SC
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Old Jul 22, 2012, 10:36 PM   #55
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I've been using a Pure Sine Cyber Power unit for about two years now. Tastes great and it's less filling.
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Old Jul 23, 2012, 03:42 PM   #56
nanofrog
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Quote:
Originally Posted by ScottishCaptain View Post
That's the closest thing I could come to finding something like this. Skip past midway when he engages the UPS, and much to my horror- that thing is throwing off a square wave- but there doesn't appear to be any significant over-voltage (if any) at all.
No, the over-voltage occurs within the APFC based PSU itself, not the UPS's stepped output.

To test if this is the case, it requires obtaining the desired APFC based PSU, opening it up, and hooking either a TRMS DMM or better yet, an oscilloscope to the primary caps, and watch for the peak voltage.

Most aren't able to do this as it requires special equipment and skills.

Nor is it a guarantee that this will be the case, as there are variations in APFC designs, such as whether or not they have a sensing circuit as part of the APFC in order to control the charging cycle of the primary caps. IF this is missing, the cap is charged "blindly" based on a fixed charge cycle (milliseconds, say on the order of 16ms). But an adaptive implementation can adjust the charge cycle to make sure the primary caps are not overcharged.

The reason to be concerned IMHO, is that computers are built out of parts from the lowest bidder. So cutting corners (i.e. eliminating additional circuitry) from the design allows them to cut costs, either in order to meet budget, or increase their margins (PSU ODM, not necessarily the system vendor, but it's not uncommon for this to happen at both the ODM & system vendor level, so a double whammy).

So the safest thing to do IMHO, is run a more suitable type of inverter, which is a PWM based unit (still stepped, but has enough steps that the peak voltages in the caps don't exceed their ratings), or better.

Quote:
Originally Posted by ScottishCaptain View Post
And I'm not questioning the fact that a square wave could potentially be a really, really bad thing for -any- power supply that expects a sine wave, I'm just on the fence about the fact that it will actually cause irreparable damage.
Take what you know, then add in the fact the peak values can exceed the cap's ratings, and you should have a reasonable understanding of what's going on in both early and less expensive units (in regard to manufacturing cost, not retail, which can be hard to gauge without opening up the unit and performing a tear-down).

Quote:
Originally Posted by ScottishCaptain View Post
I've just never heard of a square wave inverter *damaging* a PSU.
Now you have.
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Old Jul 23, 2012, 11:22 PM   #57
akadmon
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I've been using a MP (1,1 and now 5,1) for nearly 6 years without a UPS, and I never ran into problem. I don't need another box cluttering my office! Unless you're running mission critical apps or huge simulations that can be paused gracefully if given a chance (saving hours, if not days of rework), a UPS is a waste of money, I think. Or am I missing something?

EDIT:

Of course, there are gamers among us, who just couldn't bear losing whatever it is that they got.
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Last edited by akadmon; Jul 23, 2012 at 11:27 PM.
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Old Jul 24, 2012, 02:27 PM   #58
nanofrog
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Quote:
Originally Posted by akadmon View Post
I've been using a MP (1,1 and now 5,1) for nearly 6 years without a UPS, and I never ran into problem. I don't need another box cluttering my office! Unless you're running mission critical apps or huge simulations that can be paused gracefully if given a chance (saving hours, if not days of rework), a UPS is a waste of money, I think. Or am I missing something?
Assuming lost work isn't an issue, and the quality of the power off of the wall is always within spec (no brown-outs, excess noise, frequent outages <black out>, or spikes), then this is feasible.

But the part you don't notice, yet tends to be very important, is that most power utilities do not supply ideal power (brown-outs, black-outs, spikes, and noise).

This is where a good UPS will cover you, as it can deal with these issues by design, particularly those that wouldn't cause the inverter to kick in on a line interactive type (usually what most are), thus reducing, if not completely eliminate, equipment damage due to poor power conditions.
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Old Jul 24, 2012, 02:30 PM   #59
numbersyx
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Quote:
Originally Posted by johnnymg View Post
I've been using a Pure Sine Cyber Power unit for about two years now. Tastes great and it's less filling.
+1 but only if you add salt and pepper....

On a serious note, this has saved me twice. My area goes through periods where the power cuts out momentarily and the Cyber Power steps in. When running normally it is whisper quiet....
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Old Jan 8, 2013, 09:10 PM   #60
adam9c1
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what about this:

APC SMART-UPS 1500 1500VA 980W SUA1500RM2U 2U UPS BACKUP
ebay item 110996477433

Manufacturer: APC
Model: Smart UPS 1500 Rackmount 2U 120V
Condition: Refurbished with New Batteries
Part Number: SUA15000RM2U
Maximum output: 980 Watts / 1440 VA
Typical backup time at half load: 26.5 minutes (490 Watts)
Typical backup time at full load: 7.4 minutes (980 Watts)
Output Waveform: Sinewave
Warranty: 1 Year Full Replacement Warranty, 30 Day Money Back Guarantee!

APC Smart-UPS 1500 SUA1500RM2U Rackmount 2U User's Manual

Output:
Output power capacity
980 Watts / 1440 V
Max Configurable Power
980 Watts / 1440 V
Nominal output voltage
120V
Output Voltage Distortion
less than 5% at full load
Output Frequency (sync to mains)
47-53Hz for 50Hz nominal , 57-63Hz for 60Hz nominal
Crest Factor
up to 5 : 1
Waveform type
Sinewave
Output Connections
(6) NEMA 5-15R

Input:
Nominal input voltage
120V
Input frequency
50/60 Hz +/- 3 Hz (auto sensing)
Input Connection Type
NEMA 5-15P

Cord Length
6 feet ( 1.83 meters )
Input voltage range for main operations
82 - 144 V
Input voltage adjustable range for mains operation
75 - 154 V
Batteries and Runtime:
Battery type
Maintenance-free sealed Lead-Acid battery with suspended electrolyte : leakproof
Replacement battery cartridge
RBC24
RBC Quantity
1
Typical backup time
at half load
26.5 minutes (490 Watts)
Typical backup time
at full load
7.4 minutes (980 Watts)
Communications and Management:
Interface port
DB-9 RS-232 , SmartSlot , USB
Available Smart Slot Interface Quantity
1
Control panel
LED status display with load and battery bar-graphs and On Line : On Battery : Replace Battery : and Overload Indicators
Audible alarm
Alarm when on battery : distinctive low battery alarm : configurable delays
Emergency Power Off (EPO)
Optional
Surge:
Surge energy rating
459 Joules
Filtering
Full time multi-pole noise filtering : 0.3% IEEE surge let-through : zero clamping response time : meets UL 1449
Physical:
Maximum height
3.50 inches (89 mm)
Maximum width
17.00 inches (432 mm)
Maximum depth
18.00 inches (457 mm)
Rack Height 2U
Net weight
63.00 lbs. (28.64 kg)
Shipping Weight
70.20 lbs. (31.91 kg)
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Old Jan 8, 2013, 10:44 PM   #61
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Quote:
Originally Posted by adam9c1 View Post
what about this:

APC SMART-UPS 1500 1500VA 980W SUA1500RM2U 2U UPS BACKUP
ebay item 110996477433

Manufacturer: APC
Model: Smart UPS 1500 Rackmount 2U 120V
If you have a rack to mount it in, sure. It's not a standalone model. I have the standalone SUA1500 and it's excellent.
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Old Jan 8, 2013, 10:54 PM   #62
adam9c1
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Are replacement batteries same price for the floor standing and rack mount?
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Old Jan 8, 2013, 11:05 PM   #63
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Originally Posted by adam9c1 View Post
Are replacement batteries same price for the floor standing and rack mount?
I'm sure the batteries are completely different, being that they'd have to fit into a flat 2U chassis, and therefore I'd expect the price to be different as well. The normal cube-shaped one I bought for my SUA1500 (again, non-rackmount) was a little over $100 from APC, if I recall correctly.
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Old Jan 8, 2013, 11:18 PM   #64
adam9c1
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thank you sir

$100 is pretty cheap (comparing to what I see on ebay)
Are there different capacities batteries that fit the same enclosure possibly?
I understand one is 2U unit and one is a brick thus different size batteries.

I was purly trying to understand if one kind is similarly priced to the other.
I actually would rather have the floor standing, the rack mounts would sit on the floor anyways

Can the floor standing unit also accept a management card?
I only want this so I can remote into it and run a self test, schedule self test once a week and get an email back.
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Old Jan 8, 2013, 11:33 PM   #65
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Originally Posted by adam9c1 View Post
thank you sir

$100 is pretty cheap (comparing to what I see on ebay)
Are there different capacities batteries that fit the same enclosure possibly?
I understand one is 2U unit and one is a brick thus different size batteries.

I was purly trying to understand if one kind is similarly priced to the other.
I actually would rather have the floor standing, the rack mounts would sit on the floor anyways

Can the floor standing unit also accept a management card?
I only want this so I can remote into it and run a self test, schedule self test once a week and get an email back.
The 2U rackmount model takes four RBC24 batteries, which are $350 from APC. The standalone SUA1500 takes one RBC7 battery, which they sell for $180. You could find them cheaper somewhere like eBay, I'm sure. I think I might have received a discount from APC or something, but maybe I did pay $180... I just don't recall anymore.

Here's a place selling a set of all four batteries for that rackmount for $76. I'm generally accepting of 3rd party batteries, but I tend to be a little more cautious when it comes to the battery that will sustain my business machine. Use your best judgment.

I don't know about remote management. I know my SUA1500 is recognized by my Mac Pro, and can be configured in the System Preference panel.

----------

By the way, that 2U model you posted about says it has fresh batteries, so you don't need them for a long time anyway. Not sure if you noticed that.
Quote:
Originally Posted by adam9c1 View Post
what about this:

APC SMART-UPS 1500 1500VA 980W SUA1500RM2U 2U UPS BACKUP
ebay item 110996477433

Manufacturer: APC
Model: Smart UPS 1500 Rackmount 2U 120V
Condition: Refurbished with New Batteries
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Old Jan 9, 2013, 04:19 AM   #66
Philscbx
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Originally Posted by adam9c1 View Post
Are replacement batteries same price for the floor standing and rack mount?
The only difference in rack mount - the two 12v SLA Batteries are simply turned on their side.

I've used a rack mount for 6 years on it's edge standing next to Cinema Display.
On it's edge takes only 3" foot print on the shelf, vs hidden from view.
If it chirps-I know it just took care of business..the same time the lights dimmed for a micro second.

Having so many extra outlets easy to get at of the UPS, allows me to use them for rechargeable battery chargers - cell phone chargers - ETC.

I just installed new batteries couple weeks ago, now it decides to have issues
going into alarm mode, and won't go silent w/o shutting down.
Manufacturer claims something must have caused a main board issue.

I'm looking at another rack mount, and now with extra 24v battery pack,
It could easily double back up time and provide lighting at night at the same time.

2 - Power-Sonic 12V/8Ah Sealed Lead Acid Battery with F2 Terminal Fire Retardant
SKU: PSH-1280FR (8081)$28.99 - $57.98 http://AtBatt.com/
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Last edited by Philscbx; Jan 9, 2013 at 05:08 AM. Reason: Battery Listing
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Old Jan 9, 2013, 04:47 PM   #67
adam9c1
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is it possible to add external battery pack to the floor model like I know some rack mounts have?
I don't think this is huge, I think I'd just get another unit for the other computer.

main unit:
my mac pro, one monitor, modem, router, and VOIP adapter when I get that.

2nd unit
my windows tower and one monitor
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