# Another Meanwell Question



## Rotordriver (Nov 25, 2011)

After looking at the previous thread on the Meanwell, I've been a little more curious about them. I purchased the TE Revolution with the Base Station Super Receiver. This receiver requires a linear power supply. Not knowing anything about power supplies and not understanding any of the info on Meanwells web site, can their power supply be used on my setup or will I need a PWC to Linear adapter? Also, do the on-board receivers require linear as well?

This is the last thing I need to get my outdoor layout going. 

Thanks


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## Dan Pierce (Jan 2, 2008)

When a supply states it has a regulated output, that is linear. 

So, there are 3 basic types of power supplies. 

Usually cheapest: Rectified AC, output is DC but no filtering, creates hum in sound units. Example, LGB early sets had the 5003/110. 
Mid range priced: Unregulated, power drops with increased load and could develop ripple (AC line ripple on the output). Aristo Ultima is an example. 
High end the best types Regulated supply Meanwell as well as Aristo elite and many others. 

There are many other sources for DC power packs, and for light duty I like the discarded laptop power packs. These have 20 volts and are 4 amps and are a regulated output. 

I even saw a 20 volt 6 amp unit recently. Once the laptop motherboard dies, it is cost prohibitive to replace it and cheaper to just get a complete new laptop. Power pack is great for the trains, esp the work bench.


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## Greg Elmassian (Jan 3, 2008)

The term "linear" has gotten sort of messed up in this community as opposed to how it is used in the world of electronics. 

A power supply that puts out "direct current", which means is not varying like AC, is what many people call "linear" in this hobby. 

Dan's definition is flawed in that respect, you don't need a regulated output to be considered "linear". 

This term is normally used to mean "not pulsed" or "not PWM (pulse width modulated), a type of pulse power" or not AC. 

so basically, if you have a device designed to drive a locomotive motor, most modern circuits output PWM... it makes less heat, and is cheaper. 

The problem with PWM is feeding it to circuits like electronics or sound units can cause erratic results, the typical situation is medium speed to a motor on PWM might be interpreted as full speed on a sound decoder. 

So, the "PWC to linear adapter" is basically a filter that converts AC (PWM) to DC (linear). 

(Now this is not all strictly by the book, since PWM is really a pulsed power that does not alternate polarity like true AC, but the concept is converting pulses to smooth constant DC). 

Regards, Greg


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## JPCaputo (Jul 26, 2009)

Meanwell power supplies put out "pure" dc without the 60 hz ripple. They are light weight switching power supplies that filter the output. When the output capacitors fail, it will put a lot of noise in the dc. They are cheap and easy to change out when needed.


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## Greg Elmassian (Jan 3, 2008)

I forgot to add, linear power supplies are very expensive, and not very common any more... 

Switching power supplies can still have ripple, just at a higher (the switching) frequency. 

Never had a problem with any of the meanwells, and as stated above, they are inexpensive. 

Greg


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## JPCaputo (Jul 26, 2009)

Linear power supplies are my favorite, you can tell power and quality by weight, heavier is better. They are generally bulletproof and easy to repair, or gut and redo when needed keeping the transformer. 

Mean well supplies if anything besides the output capacitors leak are extremely difficult to repair. Most often throw away and buy new.


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## Greg Elmassian (Jan 3, 2008)

The few linear supplies I have use expensive output transistors, and maybe easy to repair, but the parts are not cheap. 

I have about 3 laboratory power supplies, favorite one by HP... 

I would agree on the throw away on the switching supplies, that's because usually the failure seems to be in the switcher, not the output transistors... in my experience. 

Greg


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## JPCaputo (Jul 26, 2009)

The output transistors are expensive, good news is usually only 1 blows at a time when designed right. Replacing 1 of a bunch needs the exact same transistor. If they all blow, they can be substituted for cheaper versions with similar specs for hobby use, base and collector current are the key specs. 

I've done my own darlington arrangements to replace expensive darlingtons by using a 3055 and a general purpose npn transistor in darlington configuration. 

I agree it is not OEM quality or lab quality,but it gets the job done for less $


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## Greg Elmassian (Jan 3, 2008)

Yeah, I hear you. I had one quit recently, it had a germanium transistor... needless to say, it was not repaired... 

Greg


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## Rotordriver (Nov 25, 2011)

Seriously guys... I hardly know squat about power supplies and electrical engineering. Transistors, 60 hz ripple, darlington arrangements is all over my head. 

I appreciate your comments but the question of this thread is still unanswered. If I were to buy a Meanwell SP-320-24 for my TE revolution, do I need a PWC to Linear adapter?


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## JPCaputo (Jul 26, 2009)

The mean well is a linear ( DC ) not pulsed power supply. I have read that many people run them for TE revolution systems.


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## Greg Elmassian (Jan 3, 2008)

Dan answered your question, the first post in response. 

The rest of the thread was also meant to be educational... apparently not appreciated, since there was enough explanation to allow you to answer the question yourself too. 

Well, at least we had fun... 

Greg


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## Rotordriver (Nov 25, 2011)

@import url(http://www.mylargescale.com/Provide...ad.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css); Posted By Greg Elmassian on 15 Jan 2012 03:42 PM 
Dan answered your question, the first post in response. 

The rest of the thread was also meant to be educational... apparently not appreciated, since there was enough explanation to allow you to answer the question yourself too. 

Well, at least we had fun... 

Greg 
First of all I did appreciate the comments... That's why I said, "I appreciate the comments" in my last post. 

Second, I thought Dan answered the question too but your next post seemed to suggest he was wrong when you said his definition of linear was flawed and you followed it up by saying that linear power supplies are not very common.

Greg, you gave a lot of good information on a previous thread of mine asking about the USA Train Power 10. You said in that thread regarding PWM and Linear, "Sorry, it takes a bit of knowledge to figure this stuff out and the answer to the question is probably not public knowledge... we need a person with a 'scope to check it out." It's because of this information that I am asking these questions. I'm not trying to be a smart-ass, there only seemed to be some conflicting opinions.

I'll take the info as: Meanwell supplies are probably fine. Thanks


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## Greg Elmassian (Jan 3, 2008)

Sorry Rotor! 

I see your point. 

Basically anything that is not pulsed on the output is ok. 

The only way you would get in trouble is when you start "ganging" systems in series. Many people have tried to take the output of a control system and feed it into another. 

There's really no "power supplies" that put out pulses, the pulse output power comes from a controller or something like a Revolution. 

Sorry for the confusion. 

Greg


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## Rotordriver (Nov 25, 2011)

@import url(http://www.mylargescale.com/Provide...ad.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css); So am I correct in saying a power supply alone should put out linear DC power and a controller between the power supply and track doesn't actually lower the true voltage but causes pulses if not at full power to mimic lower voltage causing the train to run slower? (deep breath)

...or something like that


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## krs (Feb 29, 2008)

If I go back to the first post in this thread it says: "This receiver requires a linear power supply." 

Strictly speaking, there is no such thing as a linear power supply. 
What they probably mean is a DC power supply that uses a linear regulator as the control element. 

I decided to see what the Wiki had to say about that - not that the Wiki is always correct, the refer to it as a "Linear Regulated Power Supply" 
I can live with that terminology. 

However - the key here is that they make a distinction in the Wiki between a "Linear Regulated Power Supply" and a Switched-mode Power supply. 
http://en.wikipedia.org/wiki/Power_supply#Linear_regulated_power_supply 

Fair enough, but if the requirement is really a "Linear Power Supply" and they mean a "Linear Regulated Power Supply", then that would leave out the Meanwell as an option since it is a switched-mode power supply. 

Why the requirement? 
That's another question.


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## Greg Elmassian (Jan 3, 2008)

Most of this confusion comes from Aristo and the conventions used on that forum. That stems from the Linear / PWM switch (Aristo calls it PWC) on their trackside TE. 

What has happened is that people were powering their tracks with this Trackside controller, and then some people tried to put decoder-equipped locos on the track while pulse power (PWM) was on the rails. Some decoders went nuts, so people needed to filp the switch to "linear output"... 

The terminology has always swirled around Aristo stuff and people get "warned" but the concept of what is happening is not really clear. 

I guess you COULD have a linear power supply that was unregulated, but why would someone do anything except have a transformer, a bridge and maybe a filter cap. That "qualifies" from the "Aristo sense", but it's really a weird concept. 

Regards, Greg


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## Rotordriver (Nov 25, 2011)

KRS,


In the box with the Revolution and Super Receiver is a paper that says this:

_"We've noticed that we're getting calls from people using power supplies with controllers that are not Pure Linear DC but by power that has half wave pulses. The Revolution works best on track power with our own Crest power supplies and they can be attached directly to the track without an intervening controller. When using the Revolution receiver with track power you must use Pure Linear DC. If you are using a PWC power supply system you must have the new PWC-Linear Adapter CRE 57091." _


Like Greg said, I believe it is because of the decoders (Which I am not running at this point but want to have the option).


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## Greg Elmassian (Jan 3, 2008)

That reference to "an intervening controller" is what I referred to in my post. 

"Pure Linear DC" is a phrase that is an invention of Aristo. 

Translate to: filtered, low ripple DC, and you and the rest of the world will understand. 

Now, to really muddy the waters, Ron Bodnar has run Revolution TE-equipped locos from a track powered by a Revolution TE... so what they are saying is not strictly true... the paper in the box is from when they were first released, not as current as Ron's data: 


*http://trainelectronics.com/ART5700...nother.htm*

Is your head spinning yet?

Greg


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## jmill24 (Jan 11, 2008)

Rotodriver, Not train related but your guitar logo. Is that a Schecter?.............Jim


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## Rotordriver (Nov 25, 2011)

@import url(http://www.mylargescale.com/Provide...ad.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css); Posted By jmill24 on 16 Jan 2012 12:28 PM 
Rotodriver, Not train related but your guitar logo. Is that a Schecter?.............Jim



No, its a Carvin CS-6. I ordered it about 3 or 4 years ago and am very happy with it, not to mention it is absolutely beautiful.


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## krs (Feb 29, 2008)

Posted By Rotordriver on 16 Jan 2012 12:10 PM 
KRS,


In the box with the Revolution and Super Receiver is a paper that says this:

_"We've noticed that we're getting calls from people using power supplies with controllers that are not Pure Linear DC but by power that has half wave pulses. The Revolution works best on track power with our own Crest power supplies and they can be attached directly to the track without an intervening controller. When using the Revolution receiver with track power you must use Pure Linear DC. If you are using a PWC power supply system you must have the new PWC-Linear Adapter CRE 57091." _


Like Greg said, I believe it is because of the decoders (Which I am not running at this point but want to have the option).

To me that Aristocraft statement says that it is definitely OK to power the Revolution with a Meanwell power supply and no, you do not need a PWC to linear converter at the output.
The Meanwell supply will gice you DC with just a few millivolt of noise, less noise than you will get from a traditional Bridgewerks supply for instance that uses heavy step-down transformers.

Knut


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## krs (Feb 29, 2008)

Posted By Greg Elmassian on 16 Jan 2012 12:26 PM 
That reference to "an intervening controller" is what I referred to in my post. 

"Pure Linear DC" is a phrase that is an invention of Aristo. 

Translate to: filtered, low ripple DC, and you and the rest of the world will understand. 

Now, to really muddy the waters, Ron Bodnar has run Revolution TE-equipped locos from a track powered by a Revolution TE... so what they are saying is not strictly true... the paper in the box is from when they were first released, not as current as Ron's data: 


*http://trainelectronics.com/ART5700...nother.htm*

Is your head spinning yet?

Greg 


It would have been nice if some scope pictures had been posted showing the Revolution waveform at the output of the diode bridge.
That would explain what is actually going on in the scenario where the Revolution base unit is powering the Revolution receiver in the locos.


Knut


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## brucebotti (May 30, 2011)

Posted By krs on 16 Jan 2012 05:06 PM 
To me that Aristocraft statement says that it is definitely OK to power the Revolution with a Meanwell power supply and no, you do not need a PWC to linear converter at the output.
The Meanwell supply will gice you DC with just a few millivolt of noise, less noise than you will get from a traditional Bridgewerks supply for instance that uses heavy step-down transformers.

Knut

From another uninformed newbie with the same question.......Thank you! Thank you! Thank you! 

Bruce


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