Athearn Trainpak Power Pack SDK-789 (ATH9997) pulse power?

[MK]

Does anyone know if this very simple power pack have pulse power?  I want to use it for a simple layout around the Christmas tree.

http://www.athearn.com/Products/Default.aspx?ProdID=ATH9997

[DKS]

Yikes, that's a lot for a basic power pack.

For less than $10 you can have a very nice PWM (pulse) pack. Just buy a 12-16 volt wall wart, and one of these:

https://www.ebay.com/itm/DC-12V-8A-LED-Light-Protect-Strip-Dimmer-Adjustable-Brightness-Controller/222246410337

[mmagliaro]

And with an output of only 7 VA, that means it likely can't even muster 1/2 amp maximum output current.
It's really not worth $45.

Getting "friendly" pulses out of a model train controller is not hard.  Heck, just letting some of the half-wave ripple through does a really nice job with a DC motor without noise or overheating.  That's all the Kato power pack does,
and it's a lot cheaper than $45.

[MK]

No, no, no, I'm not buying it.  I got it for free at a train show.  I want to use is for that simple oval around the tree but not if it has pulse power.  Don't want to ruin my locos. 

[MK]

No, no, no, I'm not buying it.  I got it for free at a train show.  I want to use it for that simple oval around the tree but not if it has pulse power.  Don't want to ruin my locos. 

[Philip H]

No, no, no, I'm not buying it.  I got it for free at a train show.  I want to use is for that simple oval around the tree but not if it has pulse power.  Don't want to ruin my locos. 

So, mild words of advice - include information like this in your initial post.  it will help you get better more full answers.

[MK]

I can see how it was misinterpreted but I did not say I was going to buy it or if it was a good buy.  Just asked whether it has pulse power or not. 

[ChristianJDavis1]

I can see how it was misinterpreted but I did not say I was going to buy it or if it was a good buy.  Just asked whether it has pulse power or not. 

As a previous chemistry professor once taught us, "answer the question that is asked, not the question you want to answer." I did not see anything wrong with your request, nor any of the replies, but sometimes you just want the answer to the question asked.

As far as the power pack is concerned, I would never use something I have doubts about. If you have a fear that the power pack is problematic, better not to use it; even if it only saves you piece of mind.

[ChristianJDavis1]

As a previous chemistry professor once taught us, "answer the question that is asked, not the question you want to answer." I did not see anything wrong with your request, nor any of the replies, but sometimes you just want the answer to the question asked.

As far as the power pack is concerned, I would never use something I have doubts about. If you have a fear that the power pack is problematic, better not to use it; even if it only saves you piece of mind.

And in total hypocrite fashion, I never answered the question; I do not know. From the Google search I did, I could not determine that it was not pulsed, so I would say to go with my previous statement and not use something you are unsure of. The athearn is probably cheaply made, so relying on it to be safe enough is not a guarantee, and I would not risk it, even if it was free. Nothing like breaking something you bought with something you for for free.

[narrowminded]

Yikes, that's a lot for a basic power pack.

For less than $10 you can have a very nice PWM (pulse) pack. Just buy a 12-16 volt wall wart, and one of these:

https://www.ebay.com/itm/DC-12V-8A-LED-Light-Protect-Strip-Dimmer-Adjustable-Brightness-Controller/222246410337

I have used something similar, a board only, for the same purpose but using a Bachmann old time 4-4-0.  That thing has a crazy top speed so picking through some old power supplies I had laying around I found a 6 volt unit.  It gives full range of speed control and keeps the top speed down so kids can play with it without over speeding.  I put it in a small box and added a DPDT reversing switch, some small plugs for convenient connection, and it's done.  Also so small that it velcros under the table to keep the wiring neatly hidden.  All for under $5.

[MK]

As a previous chemistry professor once taught us, "answer the question that is asked, not the question you want to answer." I did not see anything wrong with your request, nor any of the replies, but sometimes you just want the answer to the question asked.

As far as the power pack is concerned, I would never use something I have doubts about. If you have a fear that the power pack is problematic, better not to use it; even if it only saves you piece of mind.

Right! 

If I can't be for sure I won't use it.  But I think this is something that is included in those Athearn "train sets" that you see around the holidays.

[Philip H]

I can see how it was misinterpreted but I did not say I was going to buy it or if it was a good buy.  Just asked whether it has pulse power or not. 

True - you also didn't say you already had it, which is why you got purchasing alternatives framed as "Don't waste your money," which you couldn't have since you already had it.

[C855B]

NOT knowing this particular product, so take this with a grain of salt...

I think you are right to doubt it. Like most not-quite-modern power pack designs, which it appears to be, it probably has a 60 or 120 Hz pulsed component at low throttle settings, tapering into pure DC at roughly 1/3 to 1/2 of the dial setting. It is probably not PWM (pulse-width modulation) like DKS's suggested LED controller. It's the low frequency of the pulse that gets small motors into trouble.

If it were me, the "me" having an oscilloscope laying around, I would connect it to a car taillight bulb or something like that with a reasonable resistive load, twist the dial around, and verify the waveform on the 'scope. Lacking that, it's what Max said, not all that useful. It might be an OK source for lighting accessories where you want to control the brightness.

[peteski]

We have a serious failure to communicate here.    I work in tech support and I encounter this on almost daily basis. Customers needing helps don't give enough info for any viable troubleshooting or for thoroughly answering their question.

First we need to define "pulse"  There is not just "pulse" and no pulse. as far a as model RR throttles go.  What that means is that none of the basic transistoraized throttles (that are not home built) produce pure DC.  Why? Because they do not have a filter cap - they just rectify the 60 Hz AC voltage from the thrnsformer. That results in a 120 Hz pulsed DC.  That is then feed to a transistor circuit which can vary the output voltage to the trac. But that voltage is still a 120 Hz DC pulse.  By DC I mean that the pulses do not flip polarity (like "regular" AC voltage does).  Some throttles which are sold specifically as "pulse" throttles have a circut which removes one of the 120 Hz peaks, which makes the DC pulses more pronounced and their frequency 60 Hz.

This type of a throttle might not play well with a small coreless motor (especually on the 60 Hz pulse setting).

Then there are the newer PWM (Pulse Width Modulated) throttles available nowadays. Those do use filtered (true) DC as their input voltage and they produce higher frequency (full voltage) pulses with variable duty cycle which results in a variable apparent DC voltage on the output. Sounds complicated but it is not. All DCC decoders have PWM "throttles" built-in to control the motor voltage.  For some technical info see  https://en.wikipedia.org/wiki/Pulse-width_modulation

PWM throttles (including DCC decoders) are safe for coreless motors).  Which brings up a question: Why are you afraid of pulsed throttle?

[MK]

Peteski, I'm going to run a simple holiday train around the tree.  I'm going to use a  DC Kato loco.  Maybe run it 2-3 hours straight at prototypical speed.  I've heard that if you use a power pack that has a specific pulse circuitry (e.g., Railpower 1370 but not the 1300) it will destroy the motor by causing it to heat up.  I think this is not PWM as I know that won't be a problem.

Let me rephrase my question then.  I have a DC loco, will it burn up with the above power pack?  I hope this is simple enough.    I note that this same power pack comes bundled with Athearn's all-in-one turnkey train sets.  I figured if it burns up locos they would get a lot of phone calls.  Unless Little Johnny runs it at warp speed.