Power Pack Transformers - Need some help

[ole6768]

First off, I will admit that electrical engineering is not this civil engineer's area of expertise. I thought that N power packs were for N scale, HO packs for HO layouts, you get the idea. Now I have test run my On30 purchases with both a N pack and a HO pack; I got better control with the N unit. But now I have seen a Bachmann transformer for G, HO and N scales! How can this be? I know Bachmann isn't a great power unit and I use MRCs. So what ratings do I look for in a power pack to run a G engine? I always thought heat would be an issue --- some thing would burn up and that would be it! Help me understand these things. And remember, I still don't understand how one can run 2 identical engines --- one forward facing and one reverse facing at the same time. Thanks for the help, Lee in Tucson

[untabubba]

Punk, I'm watching some right now. Thanks Marc

[ginzokid]

Marc first. The "externally modified" 1300 usually has a pin or some kind of blocking mechanism put on the throttle face or on the interior to prevent the rotary knob from turning all the way to full power. Micro-Trains does this or has MRC do it for them to sell these pack with and for their Z-scale trains that take a max of 10 volts. You remove the block and you will have the full range again up to the 14 or so volt out put in DC. The AC side is still at full power on these modified units. It will work just fine either way for lights and if you remember what I said about not running lamps at full power to give them a longer life, this "toned down" 1300 is perfect. Just figure the max number of bulbs per the formulas above. Now for Lee: An On30 engine actually has a motor equilivant to an HO motor, which means it will draw about 1 Amp. So the units you have for power are sufficient to run 1 or possibly 2 On30 engines each. Remember to take the VA capacity and divide it by 12 to get the Amp power available for each. I am assuming you will be staying with DC and not going DCC. That is another story for power needs. The G scale motors draw 4 amps on average. I know the math dosn't seem to add up with the 17VDC output of the Bachmann pack, but it is designed to run 1 and only 1 engine. It will work for the G. Trust me. As far as your 8 volt running measurement, that is the current you are putting into the track. The higher the number the faster the engine goes. But you knew that. All the numbers in my examples are max numbers. You always want to figure the max load on a power pack to see if you have enough juice to do what you want. The higher the VA rating on the power pack, the more range of speed control you will have. To get the On30 to run you might have to turn the knob almost half way up on a 17VA pack, but only 1/3rd up on a 30VA pack, or 1/4 way up on a 100VA pack. It's like the difference between a 4, 6 or 8 cylinder automobile. There is just more power available with a higher VA output. Also, if you have any On30 with sound in them, your power draw will almost be doubled in DC. End of lesson for today. Quiz at 11:00...... B-)

[untabubba]

Can I use a calculator on the quiz? ;)

[g-pa1]

Pete, I just picked up a new modified MRC 1300 to run with my Z train and there were no pins to limit throttle knob travel. There were however imprinted on the dial where to stop for Marklin z's and another further up to stop for Micro train z's. It works much better than the starter set N gauge transformer I was using. Much easier to control the speed of the mine train. Gene

[ginzokid]

Very interesting Gene. My question is; can you physically turn the knob past these indicated notations to get the full power from the power pack? Are there not actual stops in place? B-)

[g-pa1]

Pete, Yes I can turn the knob past the Marklin marker to the marker that says stop here when running micro trains locos. The dial goes from start to 90 at about 85 there is an 8V designation and the reminder to 'stop here when running Marklin trains' and then further after 90 is a reminder that says "stop here when running Micro Trains" and there is the 10v reminder as that is what MT can handle. However the knob will not go past the 90 number on the dial. The unit was modified by MRC.There are no physical intermediate stops from beginning to end. Gene

[ginzokid]

Gene, The knob must have a stop built into it on the inside of the housing as I believe, although you did not say so, that the dial goes up to what would be 100 at "Full". You can take the thing apart by removing the screws and look for the blocking mechanism, or send it to me and I'll do it for you. Or you can use it like it is since you are running Z scale with it. B-)

[g-pa1]

Pete, I specifically bought this transformer for the small Z Scale Marklin that runs around the mine. I don't take the knob past 40 or 50 and therefore I don't need nor plan to use this with anything else. Thanks for the offer though. MRC internally must place some kind of stop at the end of the 10v marker. I think I found some Kato silver Sante Fe passenger cars but we will see how the auctions go. Gene

[flaretired]

Can anybody tell me if I can use this as a power supply? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=7514748605&ssPageName=STRK:MEWA:IT It is a 12v 5amp supply being sold on ebay. Since my control only provides 2.5amps this should give me all the power I need. Thanks. Chuck

[ginzokid]

Chuck, Doesn't look like this is designed for model railroads except for accessories, lights, switch machines and such. Definitely not for running your trains. There is no output control. What scale are you in? 2.5 amps is a lot of power for small scales like N and HO. B-)

[flaretired]

N scale DCC. I am planning on running four trains and was told each train draws 1 amp. In the books I got it shows a power supply hooked up to my controller to increase the amps. I thought I could do it this way instead of buying boosters. I plan on having 12 blocks when I am done. Chuck

[ginzokid]

Chuck, Sounds like you will need a least four boosters (power supplies) and four power shields controlling three power districts (blocks) each. If you have the book "Easy DCC" it shows you how to do this. Are you going to have four throttles or control your four engines or run them all from one? I control my four locos with one throttle right now, but I might add a second one later for guest use. I have found the simplicity of wiring DCC is the biggest advantage and only run two power districts from the one command station and one power supply. Twelve power districts sounds like you have a huge layout. How big is it? As for that power supply you are looking at, ask the seller if he knows it will work with DCC. B-)

[flaretired]

I think my layout is small. 4'x8'. The reason for so many blocks is I plan on adding signals lights plus I have a turn table freight yard and passenger yard. Two main lines one freight and one passenger. To run block control you must have at least three blocks. I have two throttles one walk around and the command station. I want to put the blocks in while I am laying track and then add what I need as I get the money from my budget. That is why I am looking at that power supply. A 5amp power supply runs about $149.95. Also I have all automatic turnouts which I plan on using my throttles to control. With my dreams and budget might get my layout done before I die. Ha Ha. I already have power supplies to run Accessories. DCC may be easier on wiring but sure cost more. Chuck:)

[ginzokid]

Chuck, You have totally lost me. Why do you need all those blocks? You are stuffing a lot into a 4x8. I think you are still in a DC frame of mind where you have to constantly throw switches to route the power to the track. You don't need all that with DCC. The only reason you have power districts in DCC is to prevent a short circuit from shutting down the entire layout at one shot. I haven't read up on the aspects of signal controls in DCC yet, so I can't help you there, but I'm sure it is in one or more of the reference books you say you have. I presume you will have stationary decoders at each turnout so you can control it with your hand throttle. You know you have to assign each turnout a number just like each loco to control it. I'll have to read up on that more too. And don't forget the automatic reversing circuitry you will need for that turntable and any other "reversing section" you might have. I was lucky and my computerized TT control came with auto-reverse in it. I did have to buy a reversing unit for the wye though. If I were you, I would re-think all those power districts. Look at "Easy DCC" again if you have it. One booster can cover many districts. It just takes a little more insulated rail joiner positioning. B-)

[flaretired]

I am now confussed. If I want block detection so the behind train does not run into the front one, don't I need blocks? The big book of DCC shows I have to supply power to each isolated block. The same decoder that's detects the current draw as the loco enters the block can also change the signal. I just want to pre-wire may lay out so as I can afford it I can start adding the decoders and signals. Chuck 🙂