Are step down transformers bad for electronics and other transformer questions?

[aj327]

Hello all. I'm US military currently living in Germany. Luckily most of my electronic equipment is dual voltage but I recently bought a Brother Color Laser Printer (MFC-9970CDW) that is 110V 50/60 Hz. I was told by a friend who I don't think knows very much about electronics that using a transformer for long periods can actually cause damage to electronic equipment. Is this true? Would it make a difference if I only powered it on when I used it?

Also, I've read that laser printers on average consume anywhere from 400-800 watts but I can't seem to find the exact specs from the Brother website. It's a pretty large printer so let's say it even takes 1200-1500 watts. Is a 2000 watt transformer sufficient? How much buffer should I have to be on the safe side?

Also, how inefficient is it for transformers to be on and plugged in all day? They seem to always be warm to the touch and hum so I imagine it could be leaking quite a bit of energy...I'm trying to avoid "vampire power" as much as possible these days.

I was also told that since the prongs in German plugs aren't sized to reflect polarity it's easy to get the polarity reversed if you plug the transformer into the wall the wrong way, which could fry whatever you have hooked up to it. Do they sell relatively cheap polarity detectors to make sure this doesn't happen?

And finally, since my printer will be networked to my computer and in a different room I was thinking that I could plug the transformer into a power strip that I can remotely turn on and off from another room (since leaving it on 24/7 likely wastes a lot of energy). That way I won't have to leave my desk every time I want to turn my printer on. Belkin makes a power strip like this that operates via a remote from as far away as 60 feet. I assume there's no issue plugging a transformer into a power strip even if it's a surge protector? Ideally it would be great if they made a power strip that had wireless networking capabilities so that I could just turn the strip on directly from my computer, but I don't know if such a thing even exists. If it does please let me know!

Thanks in advance for the help!

 

[aj327]

Sorry one more question. Is there an advantage to getting a transformer that is also a "voltage regulator." I see that LiteFuze makes a 3000 watt transformer with voltage regulation that's only about 10 dollars more than the one they make without voltage regulation ($139 vs $129). Since I don't know what this even means really, I'm not sure if I need it or not...

 

[daddles]

When a friend makes a statement like transformers can cause damage to electronic equipment, you can ask him to explain the mechanism whereby this happens. Most engineers would regard the statement as ludicrous because every power source coming into a home or business is connected to a transformer. Every one. To give him the benefit of the doubt, there may be some critical part of his statement you left out. But the majority of AC electrical appliances' operation over the last century have involved operation from transformers; they are highly developed and quite reliable.

You need to measure the actual power consumption of your printer. Typical laser printers only consume significant power when the fuser is on (a heat source used to melt the toner plastic deposited on the page) or when running the stepper motors to advance paper through the paper path. Most modern printers have firmware that helps them reduce their power consumption when idle. One of the best tools for measuring power consumption is the $20 Kill-a-watt device. It will measure both the instantaneous power and you can also set it up to measured the total energy consumed over time. Very useful for any homeowner.

There's a tradeoff about operating things continuously vs. only turning them on when needed. Leaving them on continuously can be less stressful on the electronics (less thermal cycling), meaning you will probably get better reliability. Turning on and off only when needed obviously minimizes power consumption. I spent a lot of money on my printer a decade ago and I want it to last a long time, so I leave it continuously powered on. It was designed to go into a power save mode when unused for a specified period of time.

Most transformers are in the range of being 98% efficient or so. The energy that is wasted in "copper losses" is what you feel as heat (besides hearing some energy converted mechanical energy in the humming). Again, if you had a Kill-a-watt, you could measure the idling energy consumption of a transformer and decide whether you wanted to leave it powered on or not.

Your printer should have its AC power consumption specified on it somewhere. You should use that to guide you in picking a step-down transformer. Since a printer won't operate at its rated full power for very long, I would recommend picking a transformer with the same rating as the printer requires. I don't think there's a need to add in a margin.

I doubt the German AC lines' polarity is relevant. If the plugs can plug in either way, then equipment should operate reliably in either case. This is analogous to e.g. double insulated tools in the US -- you can plug them into the 120 VAC outlet either way (i.e., the plugs don't have to be polarized).

Just make sure your power strip has a power rating that is larger than the sum of the power loads you plug into it.

 

[aj327]

Thank you for that detailed reply. Extremely helpful!

A couple questions.

1) Do I need to get a 220v version of the kill a watt device or is it dual voltage? I couldn't find the answer on the amazon product page.

2) I just received an email from Brother telling me not to use this printer with a transformer. Do you think they're just saying this to cover their a$$, or could it be a real issue? Here's the email:

Brother Customer:

This printer is standard 110-120v. Please know that attempting to use
this machine with a transformer/converters, which is not recommended by
Brother, may damage the printer (blow circuit board inside machine),
which is very commonly seen by Brother when customer's attempt this.

Please see the watts information listed below for this machine:

Peak 1200W
Copying (average): Approximately 615W
Sleep (WLAN:On) Average: Approximately 10W
Deep Sleep: Approximately 1.8W
Ready Mode (Average): Approximately 75W


We hope this information will be useful to you. If we can be of further
assistance, please let us know. We apologize for any inconvenience.

 

[aj327]

So...should I be concerned about this email from Brother or no? I still haven't bought the transformer. Also do you think it will help to get the transformer with voltage regulation?

 

[Resqueline]

It's hard to say what makes Brother say what they do. It may be a blanket statement to cover their back against all kinds of eventualities a customer might do to it.
For example, some people might consider a small, lightweight, 1kW triac voltage adapter to be a transformer. Such a device would damage the printer.
But ordinary transformers have supplied all kinds of electronics for ages, and I can't see why the printer should be so finicky/sensitive that it would blow from such use.
Small transformers have a poor regulation factor (no-load = high voltage) but you need a big transformer (>1200VA) that inherently will have a good voltage stability.
I'm hesitant to recommend using a voltage stabilized transformer since its waveform might be quite different from the ordinary mains (sine). Do you have a link?
The question (in my opinion) is more if you should go for an auto-transformer or an isolation transformer. I'd opt for the latter (less eventualities to go wrong).
Then it might be a good idea to add a surge protector between the transformer and the printer, just as an added safety measure, just in case - something.
A transformer may have more or less of what is known as stray inductance. The printer turning off the heater could induce a voltage spike due to this.
Without picking the brains of Brothers engineers I can only come up with theories, and I can't guarantee you won't encounter surprises.

 

[daddles]

I'd recommend using an autotransformer. I've been powering my 1 hp lathe from 240 VAC for 25 years from an autotransformer, so I know they work well (I've also used my 10 A Variac for similar type tasks over the last few decades). I see no need for an isolation transformer. When I bought my autotransformer, I just walked into a local industrial electrical supply and they had exactly what I needed.

The manufacturer's statement is a bit ludicrous, but they're probably trying to protect their butts against some of the insane things that consumers do. Personally, I'd ignore it.

 

[aj327]

Here is the 3000 W Voltage regulator transformer:
http://www.amazon.com/LiteFuze-LR-3...D4/ref=sr_1_15?ie=UTF8&qid=1319659524&sr=8-15

Here's just the regular 3000 W transformer:
http://www.amazon.com/LiteFuze-LT-3000-Voltage-Converter-Transformer/dp/B002ITXYS6/ref=pd_cp_e_1

And here's an article stating why I should never use a surge protector with a transformer. Food for thought. Let me know what your thoughts are.
http://www.gson.org/stepdown/

Thanks very much!

 

[aj327]

Since you guys are clearly the experts would you mind providing me with a specific product name or link that I could check out.

 

[davelectronic]

printer power supply

Stone the crows, how can an AC triac control circuit be a transformer, it controls AC but is in no way a substitute for a step down transformer, it can crudely control a transformer for non critical applications, but not for the above use.

Modding is fun, killing expensive media / PC gear is not fun.
Not to see the ability to mode stuff i would find a handicap for me.

But in this instance i would not cut corners. Some believe you need super close tolerance 0 ripple psu's to control a DC motor for none critical use, mmm, ok yer right sure.
Dave.

 

[davenn]

And here's an article stating why I should never use a surge protector with a transformer. Food for thought. Let me know what your thoughts are.
http://www.gson.org/stepdown/

Thanks very much!

just note .... thats specifically an auto-transformer used for step down

not a normal transformer, big difference !

Dave

 

[jackorocko]

Here is the 3000 W Voltage regulator transformer:
http://www.amazon.com/LiteFuze-LR-3...D4/ref=sr_1_15?ie=UTF8&qid=1319659524&sr=8-15

Here's just the regular 3000 W transformer:
http://www.amazon.com/LiteFuze-LT-3000-Voltage-Converter-Transformer/dp/B002ITXYS6/ref=pd_cp_e_1

And here's an article stating why I should never use a surge protector with a transformer. Food for thought. Let me know what your thoughts are.
http://www.gson.org/stepdown/

Thanks very much!

The third link clearly states autotransformers are the problem. As long as you buy an appropriate transformer with the coils isolated to each other this would be a moot point.

edit: doh, I feel dumb now, always read all post, davenn beat me to it by 5 hours

 

[Resqueline]

The issue with surge protectors is a result of US gear expecting a specific phase to be neutral, and the use of an auto-transformer.
That would not be a problem with an isolating transformer, which is exactly why I recommended one.
They're heavier than an auto-transformer of the same rating but does the same job, only safer.
I wouldn't care to go higher than a 2300VA rating as most circuits will be fused at 10A anyway.
Amazon sure doesn't share much in the way of technical details, though one review mentioned isolation...

Edit: I didn't notice this second page either...

 

[daddles]

After reading the post about the surge protector frying with an autotransformer, I rescind my recommendation of using an autotransformer. I agree with Resquiline's advice that a regular transformer with isolation would be the tool of choice here.

 

[aj327]

OK, so to get straight to the point then...ummm...what should I buy? Any specific recommendations? I appreciate the academics going on here but I just want to use my 110v printer here in Germany. I'm willing to spend up to a couple hundred dollars if necessary. Thanks.

 

[jackorocko]

http://www.starkelectronic.com/st500.htm

"Safety polarized inputs"

This is what you are looking for. This model is plug and play. If you want more of a challenge then buy just a regular isolation transformer and wire it up in a box with outlets. Also, I do not see a rock solid power rating for the printer, you only guess. Well you could get out the printer and read the label on the power adapter/back of machine and tell us what the current draw is.

http://search.digikey.com/scripts/DkSearch/dksus.dll <-- here is a short list on digikey of some models with male Euro plugs, step down transformers up to 1500 watts Isolated, at $500 dollars it is certainly not cheap. This is a prime reason why you need to figure out your power consumption. Buying something to do the job ten times over is only gonna cost you an arm and possibly a leg. Also, take note, they do not convert line freq, this may very well be the reason why brother tells you not to use a step down transformer. Maybe the printer needs 60Hz, I don't really know what that would do switching to 50hz

 

[aj327]

Here is the letter from Brother that I posted above. You said that I didn't include a rock solid power rating for my printer but the below specs seem pretty thorough. Is this not what you're asking for or do you mean something else when you say power rating?

Brother Customer:

This printer is standard 110-120v. Please know that attempting to use
this machine with a transformer/converters, which is not recommended by
Brother, may damage the printer (blow circuit board inside machine),
which is very commonly seen by Brother when customer's attempt this.

Please see the watts information listed below for this machine:

Peak 1200W
Copying (average): Approximately 615W
Sleep (WLAN:On) Average: Approximately 10W
Deep Sleep: Approximately 1.8W
Ready Mode (Average): Approximately 75W


We hope this information will be useful to you. If we can be of further
assistance, please let us know. We apologize for any inconvenience.


Edit/Delete Message

 

[aj327]

Here is the link to the litefuze website. http://www.litefuze.com/products/lr-series/

Is there anything wrong with this one? It's around 60 bucks cheaper than the starkelectric box. I'm not sure if it's a gimmick or not but this box also has voltage regulation which they suggest provides a more stable current. Is this true? I'd likely get the 3000 watt model if you guys think this one is safe. I couldn't find anything mentioning "safety polarized inputs" but I don't know how standard a feature that is on these things.

 

[jackorocko]

Here is the link to the litefuze website. http://www.litefuze.com/products/lr-series/

Is there anything wrong with this one? It's around 60 bucks cheaper than the starkelectric box. I'm not sure if it's a gimmick or not but this box also has voltage regulation which they suggest provides a more stable current. Is this true? I'd likely get the 3000 watt model if you guys think this one is safe. I couldn't find anything mentioning "safety polarized inputs" but I don't know how standard a feature that is on these things.

I don't have any idea, I guess you should ask the people at litefize. But I am gonna assume that a cheaper model will possibly use an autotransformer which we already discussed is a bad idea.