Printer causes brownout, UPS wont switch fast enough

[bryanl]

A line filter costs less than a new UPS or a ferroresonant transformer. What power supply does your parents' computer use? Some have no line filters.

Most voltage drop problems in household wiring can be solved by fixing loose connections.

 

[Red Squirrel]

Out of curiosity, what is the exact model of the APC UPS causing trouble? There's more than 2 types of UPSs, there is also the middle ground, line interactive UPSs which have an autoformer that can boost and trim voltage. I'm wonder if this one is a cheapy standby type or line interactive.

Most home UPSes are standby. If it was dual conversion I'm sure this would not be an issue. I don't know if it's the EXACT model, but it looks like this one:

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BR1000G

Though that one says line interactive, is that the same as dual conversion? If yes then it's not that model, I know theirs is standby, since I did not pay much for it, maybe 100 bucks.

Not sure what PSU they use, I'd have to check when I go there.

 

[Scipio Africanus]

Most home UPSes are standby. If it was dual conversion I'm sure this would not be an issue. I don't know if it's the EXACT model, but it looks like this one:

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BR1000G

Though that one says line interactive, is that the same as dual conversion? If yes then it's not that model, I know theirs is standby, since I did not pay much for it, maybe 100 bucks.

Not sure what PSU they use, I'd have to check when I go there.

Not exactly true, cheap home UPS's are standby. Line interactive is the bulk of UPS topologies from middle end home all the way to enterprise environments. In fact, *most* UPS's in enterprises are line interactive. Only the most mission critical stuff uses dual conversation.

And if yours is line interactive like the one you linked that's very strange. Line interactive designs are very fast in switchover time. That is odd in your case then. That looks like a fairly well built middle-end UPS. I can't see why it would have this problem.

I know you ruled it out, but the wiring could be a problem in the fact that there is too much loaded on that single breaker. A laser printer shouldn't cause this. Maybe there's a lot of lights, appliances, etc or something else on the line as well? I know some contractors take stupid shortcuts like this when remodelling.

 

[Rubycon]

A line filter costs less than a new UPS or a ferroresonant transformer. What power supply does your parents' computer use? Some have no line filters.

Most voltage drop problems in household wiring can be solved by fixing loose connections.

Line filters (basic hash) are LC and keep RFI out of the lines but won't do much to help with inverse spikes.

Fully galvanic isolation from the mains in the form of a motor generator (MG) or Ferroresonant transformer will solve the problem. Unfortunately at great expense but in the case of the latter still less than correcting premise wiring issues unless it's simple, i.e. loose connection.

Even the relatively high end APC SmartUPS 3000 bolted to the floor here still shows the same input and output voltages. Only when the voltage drops to the boost point will the relay inside switch taps. A Ferrups stays at a steady 115 or 230 regardless of how much hell is breaking loose further up the line. They are amazing regulators. But they do run hot, hum, and are heavy and expensive.

 

[bryanl]

Line filters (basic hash) are LC and keep RFI out of the lines but won't do much to help with inverse spikes.

Fully galvanic isolation from the mains in the form of a motor generator (MG) or Ferroresonant transformer will solve the problem. Unfortunately at great expense but in the case of the latter still less than correcting premise wiring issues unless it's simple, i.e. loose connection.

Is there any way to do that with a junkyard full of ferroresonant transformers from Zenith TVs made in the 1970s?

 

[Red Squirrel]

I went over the other day to visit though I had forgot about that problem so did not go prepared (no tools). Their UPS does show the line voltage though, so I turned on the printer and it dropped down to 110. It was already at 118 idle. So it seems their line voltage is a bit low. I'd be curious to test at the panel but there is no way to access it. The PC did not shut down at that point though. Guessing it depends a lot on how "hard" the printer starts, if that makes sense. Perhaps when it kicks on and the AC sine wave is closer to 0 then it needs to draw more amps to make up, and it causes a bigger brownout. Just a guess though, but it's definitely random.

I showed them the power cord to the UPS and told them to just unplug it to run the printer, so that the PC is running on the inverter and not on the AC, so when the printer kicks on it wont shut down.

After looking at the possible solutions such as a dual conversion UPS, I'm thinking this may be the simplest fix. They're not ready to spend a couple hundred bucks on power filters or a dual conversion UPS.

Maybe if I can bored one day I can make an arduino based device that continuously monitors the line voltage, and if it goes below a certain threshold it kills a relay. I could then have their UPS plug through this relay. So if voltage drops to say, below 110, it will cut the power off completely and hold for at least 10 seconds, forcing the UPS cleanly into battery mode. I find what most cheap UPSes lack is a hold feature, where if the power is very dirty it just keeps it on battery for a set minimum to avoid constant switch overs.

My big UPS at home has this, it will keep it on battery for 10-15 seconds extra so even if I were to plug/unplug the cord very fast or let it arc, it would just stay on battery and not switch back and forth so many times.

 

[westom]

Their UPS does show the line voltage though, so I turned on the printer and it dropped down to 110. It was already at 118 idle.

Those numbers make the problem obvious. "you know weak connections exists somewhere between that receptacle and the breaker box." Current from a printer should never cause an 8 volt drop. In most cases, it is only a loose connection. In some rare cases, that 8 volts is reporting a serous human safety threat.

The printer should cause a voltage drop of less than 1 volt if connected only 40 feet to the breaker box. Your numbers suggest something, easily corrected inside walls, is generating 50 watts of unacceptable heat. Those numbers should have immediately caused concern.

Never cure such problems with a UPS. Solve the problem - not its symptoms.

110 is well above minimum voltage for every 120 volt computer.

 

[Rubycon]

Is there any way to do that with a junkyard full of ferroresonant transformers from Zenith TVs made in the 1970s?

I don't think that would work. Even using the cores and working from there the capacity wouldn't be very high. FRTs should be operated at less than 50% capacity for long periods of line quality is poor. Even such they are overbuilt.

 

[Red Squirrel]

Would something like this work? Though, do these actually regulate the voltage if it goes too low? Not too sure exactly what they do, I think they're more for surges than brownouts. I could plug that in first then plug the UPS into it.

http://www.tigerdirect.ca/applicatio...912&CatId=4715

I'm debating on actually picking one or two up for myself to protect my server stuff as I only have some basic "surge strips" and when I redo my power I will be able to perhaps get rid of these and use my new PDUs instead. One for UPS power and one for direct AC. So the one for direct AC will for sure have to be surge protected, but probably not a bad idea to protect the UPS too.

 

[Red Squirrel]

Those numbers make the problem obvious. "you know weak connections exists somewhere between that receptacle and the breaker box." Current from a printer should never cause an 8 volt drop. In most cases, it is only a loose connection. In some rare cases, that 8 volts is reporting a serous human safety threat.

The printer should cause a voltage drop of less than 1 volt if connected only 40 feet to the breaker box. Your numbers suggest something, easily corrected inside walls, is generating 50 watts of unacceptable heat. Those numbers should have immediately caused concern.

Never cure such problems with a UPS. Solve the problem - not its symptoms.

110 is well above minimum voltage for every 120 volt computer.

I'll have to check all the outlets on that circuit and see if I can get lucky and find a loose connection. Could also be they were "back stabbed" which is usually bad. Hopefully if it's a loose connection, it's not at the panel, since theirs is not accessible. Honestly, if I was an inspector I put a huge red tag on it. (would need a stick to do it)

 

[westom]

Would something like this work? Though, do these actually regulate the voltage if it goes too low? Not too sure exactly what they do,

Its title is a power filter. But read the specification numbers. Not a single number claims filtering. Spec numbers says it is a surge protector equivalent to many selling for $60 or $10. It operates no different than a $3 power strip except when 120 AC mains voltage exceeds maybe 330 volts.

I do not even seen any reference to a critically important 15 amp circuit breaker. And see no UL listing; essential for human safety.

Like a power strip, it only outputs the same voltage incoming from a wall receptacle. However, it sells for something like $230. If it does anything more useful than a $5 power strip, well, its specification numbers do not say so. Specifications do not even claim to meet safety standards let alone protect hardware.

 

[Rubycon]

Would something like this work? Though, do these actually regulate the voltage if it goes too low? Not too sure exactly what they do, I think they're more for surges than brownouts. I could plug that in first then plug the UPS into it.

http://www.tigerdirect.ca/applicatio...912&CatId=4715

I'm debating on actually picking one or two up for myself to protect my server stuff as I only have some basic "surge strips" and when I redo my power I will be able to perhaps get rid of these and use my new PDUs instead. One for UPS power and one for direct AC. So the one for direct AC will for sure have to be surge protected, but probably not a bad idea to protect the UPS too.

No they don't. Those are not line conditioners!

If you need a true line conditioner you're looking at something more like these here:

http://upsplace.com.au/Sola-Power-C...rtable-Power-Conditioners/sola-210-2102672500

Due to the series/parallel nature of home wiring without dedicated single use circuits, one should NEVER back wire sockets! Remember the saying the chain is only as strong as the weakest link? Well the losses of back wiring are cumulative in such an arrangement. ALWAYS side wire receptacles and switches. ALWAYS strip the wire the proper length and make sure it's covered with no less than 75% (270 degrees) around the screw on the terminals and the screws are driven TIGHT.

A DMM/DVM has a high input impedance and will never detect a marginal connection or inadequate conductor run as well.

 

[Red Squirrel]

Ouch $$$! Guess it makes sense it needs some kind of variac and high speed control circuit to bring it up/down, that or it has to act as a sorta dual conversion UPS to invert the AC phase.

But yeah I'll have to start by checking all the plugs, not sure how they were connected. Maybe I'll get lucky and it's just a loose connection. When I install plugs myself I usually use needle nose pliers to curl the tip (just the tip ) of the wire so I can wrap it around the screw and get it nice and tight. Maybe this was not done. Though I know the contractor who did the work and he's usually pretty good so I'd be surprised, but you never know, worth checking.


So guess that device I posted is just overpriced for nothing then? I was actually thinking of getting two (one for each dedicated circuit run) for my home server stuff too as right now I'm only relying on power bar surge protectors. But maybe I'll just stick with things in that price range. I don't really need line conditioning at home as my UPS seems to do a better job than my parents'.

 

[Rubycon]

The problem with buck/boost strapping and manually controlled variacs is you wind up with voltage swings, often on the brink of tolerance range, nearly all the time.

I've heard of silly tests like putting a 1.5kW load (heater) on the end socket and scanning the outlets upstream for thermal anomalies! If an outlet face feels warm for some unexplained reason, that could be it. In cases of higher loads it could get toasty enough for the thermosetting plastic to start cooking and at this point the power needs to be cut/load removed and the offender (weak/partial connection) fixed!

 

[westom]

Guess it makes sense it needs some kind of variac and high speed control circuit to bring it up/down, that or it has to act as a sorta dual conversion UPS to invert the AC phase.

Again, normal voltage for any electronics is even when incandescent bulbs dim to 50% intensity. Are your lights dimming that much? If lights are dimming only to 75% intensity, then voltage is ideal for electronics. And a potential human safety threat exists inside the walls. Cure the problem; not its symptoms.

Rubycon accurately described how all wall receptacles should be wired. Just remove a cover plate and look inside. If properly wired, then observe wires properly wrapped around the screw.

Many say a back stab connection meets code. Does that mean it is OK? Of course not. That means it is safe for humans. And can still cause appliance problems.

Which power anomaly must be solved? Harmonics? Frequency variation? Voltage variation? RFI? Floating neutral? Power factor? Noise? Floating ground? EMC/EMI? Surge? Reversed polarity? No power conditioner solves all. Identify an anomaly before fixing anything. Your computer's existing design makes most anomalies irrelevant.

Discover all receptacles on that circuit. Then connect a silly simple testing tool. Connect a clothes iron or a 10 amp electric heater to the wall receptacle farthest from the breaker box. Use a meter (or a Kill-A-Watt) to measure voltages on each receptacle. Resulting numbers identify where an excessive voltage drop exists.

 

[Red Squirrel]

All the outlets that I install I always make a little curl in the wire and wrap it around the screw, but not sure how these ones were done. So next time I visit I'll check and do some testing.

Electronics tend to be very sensitive to voltage spikes/loss so it's normal that if the voltage is going too low it causes issues, but the UPS should be picking up on that and it isin't.

 

[westom]

Electronics tend to be very sensitive to voltage spikes/loss so it's normal that if the voltage is going too low it causes issues, but the UPS should be picking up on that and it isin't.

First, a UPS (such as this one) can put 270 volts spikes on its 120 volt output. Why? Because international design standards even 40 years ago required electronics to be so robust. One chart show no damage even with spikes of up to 600 volts.

Second, spikes are harmful because so many are told so - subjectively. Most who make recommendations NEVER learn the numbers. Spike can be harmful. And then we add numbers. Those spikes are on the order of 1000 volts and higher. I once saw a spec for a Seasonic supply that claimed it could withstand up to 1800 volts.

Third, you have no reason to believe a UPS 'cleans' power. Especially since the first thing a power supply does is completely undo that cleaning. What does a power supply do? It first converts 'cleanest' 120 volts into radio frequency spikes of well over 300 volts. then it 'cleans' that much dirtier power. Just one of so many reasons why electronics are so robust.

Fourth, a protector too close to electronics and too far from earth ground can bypass that protection. We even proved that by replacing each damaged semiconductor. By restoring all computers to work normally for many more years. We did this stuff - and learned the numbers. Computers tend to be some of the most robust devices in a building. But that is not popular among many who only know what they were told; who did not first learn how electricity and electronics work. Who did not first read databooks.

UPS only does what its numeric specs says it does. Its ability to avert spikes is near zero. Best protection is inside the power supply for each electronic appliance. That protection is often superior to what a UPS has to protect its own electronics.