Soundtraxx Blunami Upgrade: 2200 or 4408?

Kyle Paul, A Fellow "Train-Nerd",

A quick answer is find out what the max amp draw is on that locomotive, if two amps or over go with the 4408. Max rating on the 2200 is 2 amps, max for the 4408 is 4 amps.

Ray

The amperage draw is most important.   If it is drawing 2 amps or more, it will blow up the 2200.    It can't hurt to  use the 4408 even if the amperage is less - at least it can't hurt the decoder or loco - it will hurt your wallet.

The important question is just how much current that engine draws when pulling a significant number of cars up the steepest hill or around the sharpest curve that it will encounter, at the highest speed you expect it to run under such circumstances.  The number of cars should be what you consider to be the "typical maximum" that it will pull.  If the current draw is 1A or less, the 2200 will do.  Any more, use the 4408.  That size engine should not have a "current hog" motor that would challenge the 4408.

The 4408 is still reasonably small for O scale. I managed to pack one into an Atlas SW9, along with one of their current keepers and new speaker. I was wiring to work on A/C track, so I squeezed a rectifier in there as well. It was a tight fit, but works great. Now I'm refitting another 4408 into a broken PS1 FP40PH. There's tons of room in there, so much so that I'm contemplating dead-rail and multiple speakers for it. Cheers!

Fred

I just learned about this. Can you retrofit post war engines with this as a pulmotors will run great on dc? This sure sounds like an interesting way to go as lionel really has dropped the the ball bad on remote control to me.

@Ccriss posted:

I just learned about this. Can you retrofit post war engines with this as a pulmotors will run great on dc? This sure sounds like an interesting way to go as lionel really has dropped the the ball bad on remote control to me.

A pullmor running on DC would draw waaaay more current that even a 4408 could provide. I believe there are 8 amp DCC decoders that might be able to handle them but you  would have to add a Bluerail board if you wanted remote operation on AC track. Cost would likely be more than the engine alone is worth.

Pete

Echoing Pete above, I would not attempt to drive a Pullmor motor with the current Blunami cards.  Or a Mabuchi RS550 can motor.  They're current hogs.

How about williams can motors? Would it work on them as they don't draw much juice as they are dc?

I am watching a video I just found. It looks like it should work with the williams dc can motors. Please correct me if I'm am wrong. I have some nice williams engines I would like to this with. Thank you all for your help and sharing of information.

@Ccriss posted:

How about williams can motors? Would it work on them as they don't draw much juice as they are dc?

No problem with most Williams Post War reproductions. Note what Karl said about 550 motors used in a lot of their scale brass steam engines.

Pete

The Blunami 4408 can handle most Wiiliams can motors. Wiring dual motors in series is a generally good step in a Blunami installation. With series wiring, I have been able to use the 2200 as well, but one needs to be careful.

Ah, interesting tip about series working. I was just wiring up my MTH F40PH last night and set it up as parallel. Maybe I should rewire.

I am currently working on adding a BLU-4408 in a Santa Fe with pullmor motors.  According to Soundtrax it is possible to run pullmors naturally after converting the AC track voltage to DC.

@Ron Heb posted:

I am currently working on adding a BLU-4408 in a Santa Fe with pullmor motors.  According to Soundtrax it is possible to run pullmors naturally after converting the AC track voltage to DC.

How do plan to reverse motor rotation?

Pete

I am not that far yet, been working with soundtrax.

It's easy enough to add a rectifier which will make a Pullmor motor "look" like a can motor to the Blunami.  If you search the Forum, you'll find circuit diagrams for doing this.  The motor can then be reversed by reversing polarity to the brushes, just like any DC motor.

A single Pullmor in good working condition will probably draw fewer than 3 amps under load.  The fact that most locos with Pullmor motors don't also have rubber tires is a good thing!  When the loco is overloaded, its wheels should spin, which greatly reduces current draw compared to what you would get on a rubber-tired loco at full stall.  If your diesel has two motors, that complicates things because in a worst-case scenario it would draw more than 4 amps.  Test it on the rails by snugly pinching the rear coupler (NOT by pushing down on it!)  Just make sure to disconnect the headlight, smoke, lighted passenger cars, etc., so your amp reading is limited to just the motor(s).

A couple of other challenges:  Pullmors have a flat commutator so the brushes will tend to spark more than they would on the drum-style commutator of a can motor.  This creates radio frequency interference.  That's one reason Lionel used shunted brushes and snubber capacitors in its TMCC locos with Pullmor motors.  Also, don't expect a ton of low-speed precision, because it's still a WW2-design 3-pole motor geared 8:1 to the wheels.  If you get it to work, please please post some photos and a video!

Today, I added blunami to a boxcar and I am tethering the boxcar to the loco using USB C. Pretty neat!

@Ted S posted:

It's easy enough to add a rectifier which will make a Pullmor motor "look" like a can motor to the Blunami.  If you search the Forum, you'll find circuit diagrams for doing this.  It can then be reversed by reversing polarity to the brushes, just like any DC motor.

A single Pullmor in good working condition will probably draw fewer than 3 amps under load.  The fact that most locos with Pullmor motors don't also have rubber tires is a good thing!  When the loco is overloaded, its wheels should spin, which greatly reduces current draw compared to what you would get on a rubber-tired loco at full stall.  If your diesel has two motors, that complicates things because in a worst-case scenario it would draw more than 4 amps.  Test it on the rails.  Just make sure to disconnect the headlight, smoke, lighted passenger cars, etc., so your amp reading is limited to just the motor(s).

A couple of other challenges:  Pullmors have a flat commutator so the brushes will tend to spark more than they would on the drum-style commutator in a can motor.  That's one reason Lionel used shunted brushes and snubber capacitors in its TMCC locos with Pullmor motors.  Also, don't expect a ton of low-speed precision, because it's still a WW2-design 3-pole motor geared 8:1 to the wheels.  If you get it to work, please please post some photos and a video!

Ted, Pullmors draw 3 amps because the field is in series with the armature. Put them in parallel and they draw twice as much. You can add a bridge to power the field off track voltage so only the armature is powered by the Blunami. If you want constant speed then field voltage would have to be regulated. Bottom line working with Pullmors requires more large components than using permanent magnet motors.

Pete

@TheRambles posted:

Today, I added blunami to a boxcar and I am tethering the boxcar to the loco using USB C. Pretty neat!

I see that you're using the low-current DC>DC converter/regulator that's available from many sources.  Its output capacity is limited.  Fortunately, the current draw of your loco's motor is probably low enough that the converter/regulator not overloaded.  Neat idea of using USB-C wiring components, which are OK for a low current installation like this.

Can you add a current keepers to the 2200 module.

us the 4400 as the inrush on motors sometimes will cause the Blunami to go into its safety mode and shut off before the loco gets moving and the draw goes down. soundtrack decoders all will shut off before an overload will destroy them.

@NHVRYGray posted:

Can you add a current keepers to the 2200 module.

Yes, they work in either the 2200 or 4400.

Pete