DC (only) Power Pak problem (??)

[LDBennett]

I have the small HO Bachmann power pak and it is doing weird things. I may be over taxing it. I am running the large Con-Cor MU mP54 interurban powered car and trying to run accessories off of the AC accessories output at the same time. The accessories are taking 50 MA at 16 VAC. The car runs fine but the AC accessories turn off. Turning off the power pak, waiting for a few seconds, and turning it back on again revives the accessories but only briefly. I actually have two of these (a spare) and they both do exactly the same thing. Smaller trolleys don't seem to do this.

What is the AC out max for this power pak? Am I tripping an internal AC accessories circuit breaker?

Can anyone suggest a much bigger DC only throttle with both DC for the HO trolleys and 16VAC for the accessories. Price is no consideration but there will never be any load bigger than one or two trolleys but many accessories. There is no requirement for any other features as I am incorporating Microcontroller operation with auto reverse. The throttle setting pretty much will be adjusted once for the particular trolley's desired speed and left there (no momentum required or wanted).

I have considered splitting the load between the two little Power paks but I am anticipating adding six switches to the AC load besides the current almost continuous 50 ma AC accessory load so a bigger throttle set up may be called for (??).

Anyone got some thoughts on this?

LDBennett

[sd24b]

might try a separate power pack for your accesories or a pack with more output. 

[Joe Satnik]

Dear LDBennett,

Your controller head 46605A may have a defective PTC thermistor ("trip point" current too low).

Swap out 46605A to test?

Contact me off board for more details.

joebarbsatnik"AT"gmail"DOT"com

Hope this helps.

Sincerely,

Joe Satnik

 

[LDBennett]

Here's more info:

I pulled the accessories off the trolley throttle pak and used the spare Bachmann supply to run the accessories only. Same problem. It clicks off after about a minute or so. Let  it cool down and it comes back on for a minute or so. Both Bachmann supplies do it so I am exceeding the potential for the AC output of the Bachmann Power pak.

I reduced the load, hooked up  the remaining accessories to the spare supply and it runs endlessly.

I must explain that the "accessory load" is the Miller Engineering electronic sings using their converter for 16 V Ac to the required 4.5 volts DC. The signs blink and offer about a continuous 50 ma load when they are all three in sync but can changer instantaneously  to a couple of milliamps. In addition I have one lighted building.

I have an under utilized 12 VDC supply that I can use as the source for this load of three signs and one lighted building and use the Bachmann AC output for switch motors only.

But I would like to get a better power pak, one with at least 30VA output total. But no one lists the AC output of these power pacs. My amp meter says my load is 16 VAC at 50 ma and it is tripping off. I need more than that but maybe the 12 VDC power supply will be able to do the job( ).

I'd appreciate some recommendations for a better DC power pak (at least 30VA total capacity). Is there anyone else out there besides MRC?

LDBennett

[Joe Satnik]

Dear  LDBennett,

It could be, then, that the low trip point (current draw)

is designed to protect twin-coil turnout motors from burning out (if the momentary push button switch is held down too long).

The "to track" jack uses a 1/8" TRS (tip, ring, sleeve) plug, exactly the same as a 1/8" audio stereo plug.  

Ring-to-Sleeve is variable DC power to the track, or analog speed info to the EZ-Command DCC controller head.

Tip-to-Sleeve sends 16V AC power to the EZ-Command DCC controller head.

http://www.bachmanntrains.com/home-usa/ezcommand_2010.php?ezpage=1  Scroll down to "Digital and Analog" paragraph.  

Hope this helps.

Sincerely,

Joe Satnik

Edit:  added EZ-Command info.

[LDBennett]

 Joe Satnik:

Thanks for the input but nowhere can I find a max limit for the AC output. There must be one as I am definitely seeing a shutdown at about 50 ma after about a minute or so. There is no hope of using the AC output of the Bachmann small throttle for my situation. 50 ma is nothing even at 16VAC. It blows my mind at how under powered these throttles are.

In searching for a better example, 30KVA seems to be a "big" throttle but at 15 volts that is only 2 amps and again no spec on the max AC power out.

The throttle is adequate for my uses. I have an wall power supply I use for my current Circuitron photo detector sensing and auto reverse modules. I'll just piggyback the signs and the structure load onto that supply. Fortunately the sign power converter and structure light care not about the voltage or type (AC or DC) and can run off this under utilized 12VDC wall power supply.

When I think back on my power system of my early 1950's layout, I remember that I dumped the tiny power packs and used a surplus military transformer and rectifier along with a pair of huge levered throttle potentiometers (I had a reversing track and need two throttles). I also used a hugh transformer I wound in my junior high school electricity class as an accessory power supply. I must of had tons of amps capacity. I almost wonder if I should make my own throttle and accessory power supply(??). It would be easy today.


LDBennett

[Joe Satnik]

Please contact me off board.

joebarbsatnik"AT"gmail"DOT"com

[LDBennett]

I came across a power source (actually a modifier of the DC voltage you input which could be from another throttle or from an off the shelf power supply of 15VDC) that turns the power source output into Pulse Width Modulation (PWM) to the track. I thought I'd give it a try. It will fit into my concept of computer control. My expectations are smoother running, especially at lower speeds, like the PWM gives DCC.

It is the Crest Control Pack Adapter #55401. It appears to be out of stock most places (including at Crest??) but I found one (I think?) at Train Sets Only. We'll see if they deliver.

With the accessories I have now connected to my auxiliary 12VDC supply, and the new switches powered by the small Bachmann's AC output, I think I have it all covered. I can later add a 15VDC 4+ AMP utilitarian power supply to replace the throttle part of the Bachmann power pak as the Crest unit includes a throttle control of its own. I think I got it figured out.

LDBennett

[railtwister]

I came across a power source (actually a modifier of the DC voltage you input which could be from another throttle or from an off the shelf power supply of 15VDC) that turns the power source output into Pulse Width Modulation (PWM) to the track.

.....

LDBennett

Hi LDBennett,

Beware that if you run any locos equipped with decoders or sound that are DCC/DC capable, the PWM in your new throttle may cause some of them to get confused and require a reset to factory default settings. I have a BLI Paragon 2 sound loco whose decoder seems particularly sensitive to this issue, and when I tried to run it using an MRC 2800 it started acting up. It required several hard resets before it would return to anything near normal. My other Dual Mode DCC decoders worked fine with this power pack, only the Paragon 2 had the problem.

Bill in FtL

[LDBennett]

This is a trolley layout. All trolleys are DC only with no sound. I intend on adding a stationary sound module (double bell) that will be triggered by the Microcontroller (after a stop restart cycle) I am devising to control the trolleys individually (one on the mainline at a time).

But thanks for the warning. Maybe some day I'll have DCC for another layout but that is highly unlikely.

LDBennett

[railtwister]

LD,

Don't forget that the Peter Witt and the Birney come with DCC decoders on board, but are DC enabled. The problem with A/C or PWM seems to be more common in sound decoders than mobile only decoders, so it's possible that there won't be an issue even with the PW & Birney.

Enjoy!
Bill in FtL

[LDBennett]

railtwister:

I have pulled out the DCC boards from the Peter Witt and the Birney  and replaced them with the provided dummy plug that bypasses all the DCC stuff. I've seen the schematic for the dummy plugs and as best I could tell everything is hooked up internally directly. The other engines have no DCC.

My aim is to have the operation be automatic. DCC control makes no sense for that. It is a point to point setup. My concept is to have a set of sidings where I'll park each trolley (I have six). The siding will each be a block. So I can run them in and turn off the power to that block. I'll only energize one block at a time to get the trolley out on the mainline. Once out there, it will run automatically from end to end with variations of stop times and occasionally randomly missing one of the two intermediate stations. I might then walk away and let it run for hours. Now, what in the world would I do with DCC in that scenario? Anyway, No DCC .

Thanks for the input.

LDBennett

[Desertdweller]

I have a fairly large N-scale layout that is DC only for train control.  My AC accessories consist only of 40 remote control switches.

For what it may be worth to you, I have avoided the problem of AC overload by splitting my layout into zones with the switches powered by three separate power packs.

One is an old Bachmann pack that is used for AC switch power only.  The other two are the standard Bachmann power packs with separate transformers ("wall warts").  These are used for controlling switches with AC in their local areas.  They also provide variable DC for one turntable each.  I use the throttle to control turntable speed and direction.

Control for the trains is via an MRC Dual Pack, wired through Atlas Selectors.  The AC output of this dual power pack is not used.

Generally, no more than two switch machines are ever used at the same time.  This is in the case of crossovers.  I sometimes power one switch at the same time a turntable is being powered off the same pack, with no ill effects.  The turntable motor will slow for a fraction of a second when the switch machine is engaged.  This causes no problem.

On an earlier model railroad I had, I powered the switch machines off the same power pack that ran the trains.  In this case, a running train will slow noticeably when a switch machine is turned on.

It is of course possible that you may have a defective accessory that is drawing too much current.  In general, I have found it better to keep switch machines (and, especially lights) powered from a separate power supply.

Les

[LDBennett]

 Desertdweller:

I have two of the Bachmann power packs. One will be used for trolley speed control through the Crest Control Pack Adapter #55401. it will be set for full throttle and the Crest unit will have the pot for throttle control. On this I'll not connect the AC power out at all. I'll use my spare Bachmann power pak for the five switch operation on the expansion part of the layout and only for that purpose. I have a wall plug 12VDC power supply that I'll use for the microcontroller and photodetectors. I'm using it currently for the Circuitron photodetector board and auto reversing board (which will go away with the install of the micro controller). The new associated relay board will have its own 5VDC wall plug power supply.

The accessory load is the Miller Engineering illuminated signs (three signs powered through the Miller Engr. converter to 4.5 VDC) and one illuminated structure. All of that is now tagged onto the 12VDC power supply used for the Circuitron boards. Just moving the accessory load off the power pak fixed my problem for now but with the entire control system changing with the addition of a microcontroller I may have to add still another power supply (??). Time will tell.

It would be nice to have a cleaner plan for getting power to the various users but wall power supplies are so cheap and easy. I already have what I need such that the bit of kludgyness is easy to over look. There is enough of the right power to do the job and I think I have allocated well enough for now and in the future (??). Moving the sign load/structure light load off the AC power pak output saved the day.

Thanks for your input.

LDBennett