Does BPC Divide Current to Blocks?

BPC is very much like a post war rotary switch.  You can select what block will get power from what power supply.  A single TPC  doesn't make much sense unless you intend to kill power to some of your blocks while powering up others.  Your blocks should be set up to provide whatever amperage you will need in that block at any point in time.  If you need 20 amps total a single TPC will Provide that and you can use other devices like an asc or sc2 to enable or disable blocks.

Here is a single line diagram of the components.  With this much power available, (2) PH 180's in parallel,  the (4) line fuses going to each track are very important. Without the line fuses, arc and spark welding on de-rails will happen, at least that was my experience before I installed the fuses, (7.5amps max). I also had component issues with older IC Controls BPC, where the traces in the BPC's burned.  I have two BPC's feeding (8) power blocks.


Power supply set-up. Note these are older PH135, hooked in parallel. Lower left.  Parallel connection requires Lionel part (6-14194) TPC Cable Set.

The two IC Control's BPC's.  Note that the terminals will accept 14 gauge solid wire, my choice for track power wiring.

The (8) track fuse blocks, upper middle of picture, to the left of the wire tray. One fuse for each of the (8) outputs from the (2) BPC's.

The Two TPC's. Note that the DCS is hooked in passive mode, signal only to the tracks. Track circuits do not pass through the DCS as noted in the diagram. I added the DCS signal ahead of the BPC's, Again in passive mode.

Trace repair on these IC Controls BPC.  The burned traces were caused by dead short de-rails with the only protection the TPC cutout (20 amp) that never tripped, and the two 7.5amp cutouts on the PH 135's pictured, which tripped simultaneously. 15 amps can do a lot of damage. IMO.

Thanks very much to both of you.  My understanding is that I don't really need a BPC to turn power on and off to each block section.  An ASC will do that, but I still need circuit breaker protection if I use two PHs.

Hi Baldoc

not quite sure it is clear.  The ASC and BPC are similar TMCC devices that Lionel sells. They act as on/off Controls. Almost any of the controllers - OTC eg - can be adapted for any purpose. The BPC was designed for block control. The ASC for turnouts and accessories. YES the ASC can be wired to accomplish putting power on or off to blocks, but the instructions and connecting "screws" need close following and can be somewhat confusing.  For block control, the BPC is more straightforwarD and easier to follow.

You need to take away from Mike's post that the way that you are supplying power is "parallel". So, at 18 volts  TMCC voltage, you will draw 20 amps to each block all the time. That is a lot. 

You may wish to examine how you determined that need, why you need blocks and are they really blocks in the context here.  I am guessing that you want to divide your layout into power districts, giving power to each district so that there won't be slowdowns.  The basic TMCC manual shows how to do this. In this case the PoHo's are not parallel.

Why you have the TPC in the middle is also unknown.  Generally, one uses a TPC if they plan to run conventional or PS1/2 engines.  The conventional loco with cab control will run off the track at 18 volts. 

Fuses are a must and do some research on TVS in the forum threads to get rid of spikes. This will save you a lot of headaches and later

MIKE CT. interesting use of the AVC. hadn't noticed it in your wiring diagrams in the past.

ralph

I connected two 135 watt PH's to my TPC 300's. I do just run Legacy/TMCC but at one time did run some MTH engines. I kept the setup the same. I use both a BPC and an ASC to control power to both main lines, passing track and my four way yard.

Photo taken before installing the Legacy System.

The BPC is used to switch power to TMCC or conventional.  if you are running one type of power system and simply want to turn power on and off to blocks an ASC will do that.

If you only have one power supply, aka one TCP, a BPC will not divide that power between two or blocks, it will only switch which block is controlled by it and the other block(s) will go dead.  If you have more than one power supply, aka two TPC's, you can change which block is controlled by which supply.  

This was more of an issue with control of conventional trains where you could swap in a particular supply as a train navigated though multiple blocks.  In a pure command mode your "blocks" are just power districts as the voltage should be a) constant and b) the same.  

What would be the utility of the BPC for command layouts?

For one scenario,a BPC is handy when you want one of your loops say, to run with a conventional engine, while the rest can remain TMCC.  It switches blocks from TMCC to conventional.  One of your TPCs is set to command, one to conventional and the BPC switches power to the track blocks between the two.  If you are running all command control, there is no need to use a BPC.  Furthermore, a BPC only handles four blocks.  An ASC handles eight.

That's kinda' my viewpoint, and a toggle switch is a lot cheaper for flipping one block to conventional.   Of course, with the MTH TIU in the mix, I have electronic control of command or conventional for any blocks on the variable channels of the TIU.

Thanks again to everyone for your comments. I have learned more about Command Control in one week than I did reading books for two years!  You have offered help even without knowing my particular layout situation.

I want to run both command and conventional engines, but not necessarily at the same time.  I have some childhood engines that I want to see run on my layout now and then, but most operation will be with modern engines in command control.  The layout is large enough for two, or possilbly three trains to run at the same time.  So, I do need TPCs.  From your comments, a BPC does not help much.  There are several features of my layout that I am still concerned about.

First, I have a hidden storage track area with three loops.  The idea is to run a train to the hidden area and park it there, and then bring another train from that storage area out to the upper level and take its turn around the layout.  From your comments, the est way to handle these storage loops is with on-off switches, such as an ASC.  A BPC is not appropriate.

Second, although most of the upper level can be operated in command mode, there is one section of track about ten feet long in the middle of the layout where I need to switch to conventional power to run a small 1656 switcher engine and coal car back and forth from a coal loader to a coaling station.  While this is being done, the other trains can remain in command mode.  I now assume that this special section, or block, must have its own TPC dedicated to it.

Third, if I have a Legacy engine and a TMCC engine running simmultaneously in the same block with a Legacy controller, both engines will revert to TMCC mode...right?

Thanks again for your help.  This forum is a great resource.

The track signal used by Legacy is the same as the one for TMCC.  The actual commands are different.  A TMCC engine will ignore Legacy commands.  A Legacy engine can hear and react to TMCC commands directed to its engine number.

You may want to read Nichole's post about the new Legacy Power Masers.  These may be a better choice than additional TPC's.