BlUNAMI ON TRACK POWER

Bob,

Is the converter home made or off the shelf?  Can you share some more details on the item and how it gets hooked up?

I assume it takes the 18v AC track power and converts it to DC?  Still at 18v?

Ron

You can use a full wave bridge rectifier with a filter cap and be good to go.  That’s all Sid did for install.  Just look for his video on YouTube

It appears Bob added a three terminal regulator. Blunami has back EMF but speed will change if track voltage changes so using just a Bridge and cap is not ideal plus if AC voltage exceeds 18V RMS the resultant DC will exceed the 26 volt max input.

Pete

I'd like to see them up the Blunami max voltage to at least 28 volts, that would allow a much more reasonable DC supply without having to supply amps through a regulator.

@gunrunnerjohn posted:

I'd like to see them up the Blunami max voltage to at least 28 volts, that would allow a much more reasonable DC supply without having to supply amps through a regulator.

That's a lot of volts.  Why would anyone need that much power?  G scales guys don't even need that much power.

@Ron045 posted:

That's a lot of vots.  Why would anyone need that much power?  G scales guys don't even need that much power.

You miss the whole point.  It's not the power I'm worried about, it's rectifying and filtering the 18VAC track power that yields over 25 volts DC exceeds the Blunami max voltage specifications.  I just want higher voltage tolerance so I can dispense with the expensive and bulky high current regulation and just use a bridge rectifier and filter cap.

Soundtraxx Customer Service told me that the Blunami card and app will issue an overvoltage warning prior to exceeding the failure limit.  That's fine for avoiding excessive track voltage when setting a variable-voltage AC transformer (looking at you, Z-4000), but is nearly useless for protection during voltage surges.

The DC>DC buck converter card that Pete has noted, is shown in my AC powering guide document, and used in my two diesel conversions, is reasonably compact and inexpensive, plus it dissipates far less power than a linear regulator.  Yeah, fitting it in can be an issue in smaller locomotives.  I had to use "extraordinary measures" to fit everything into my Blu Geep.

The 25 VDC rectified voltage peak arises from the use of constant 18 VAC track voltage when most, if not all, locomotives are command-equipped.  You can back down the track voltage and reduce the rectified voltage peak proportionally, but that requires a variable AC transformer.  Many of us are supplying our tracks via Lionel Powermaster 180s that are not variable.

@gunrunnerjohn posted:

You miss the whole point.  It's not the power I'm worried about, it's rectifying and filtering the 18VAC track power that yields over 25 volts DC exceeds the Blunami max voltage specifications.  I just want higher voltage tolerance so I can dispense with the expensive and bulky high current regulation and just use a bridge rectifier and filter cap.

Thought the max voltage was 27?  Cutting it close but it worked in Sid’s video.

@superwarp1 posted:

Thought the max voltage was 27?  Cutting it close but it worked in Sid’s video.

Yep... 27 volts.

The 4400 is 27, but the 2200 is less.  I'd like a universal solution that will address both.

@gunrunnerjohn posted:

The 4400 is 27, but the 2200 is less.  I'd like a universal solution that will address both.

The 2200 is really meant for HO and S.  A few of us have used it in some small O switchers which go slower and do not require a lot of power.  I used one in a single motor Atlas SW9 and another in an MTH 44 tonner.  And you know I'm Deadrail, so I'm already using DC power 11.1 volts on those two.  14.4v on all my other O scale stuff.

You should really consider the 4408 for the project you are considering with AC track power.

Ron

Ron, I want to build the accessory board for both models.

@superwarp1 posted:

Thought the max voltage was 27?  Cutting it close but it worked in Sid’s video.

Early in my Blu Shark conversion project, I had the card powered straight from rectified/filtered track power, the latter supplied by a Powerhouse 180.  The locomotive ran well and pulled a 15-car train readily.  It seemed like it held speed uphill (3%) better with the DC>DC converter/regulator installed (final version of the modifications), but the back-EMF algorithm may not have been optimized in the rectifier/filter only test.  Filter cap was 1000µF.

For best performance, Soundtraxx recommends inputting the Blunami DC supply voltage to CV215.  Absent an onboard regulator, an average value should be used, especially when a poorly-regulated transformer feeds the track (think KW variable outputs, for example).

My large steam upgrades are on hold until Soundtraxx issues a Blunami rated for at least 6 amps and has a chuff in pin. Unsynchronized puff and chuff is a deal breaker. Large and small Diesels will still be in the mix. I believe I have a regulator for small engines from Pololu, search on D36V28F12. Its fixed 12v out with 2-3.3 amps. I have run it into a 5.5 ohm load for 15 minutes and it was still cool to the touch, burned off the ceramic on my resistors though. 12v max might not work for everyone but I am hoping  it will be fine for my Plymouth Diesel.

Pete

I'm planning on using the Blunami 2200 on my Plymouth, the stall on that tiny motor is only around 500ma, I don't think it'll hurt the board.  I'm going to use a relay to energize the smoke unit, it'll be an MTH HO smoke unit so it fits.

@gunrunnerjohn posted:

I'm planning on using the Blunami 2200 on my Plymouth, the stall on that tiny motor is only around 500ma, I don't think it'll hurt the board.  I'm going to use a relay to energize the smoke unit, it'll be an MTH HO smoke unit so it fits.

John, do you have a part number for the HO smoke units. Its not jumping out at me on their parts site. I know the stock Plymouth smoke unit is fairly large. TIA.

Pete

@gunrunnerjohn posted:

I'm planning on using the Blunami 2200 on my Plymouth, the stall on that tiny motor is only around 500ma, I don't think it'll hurt the board.  I'm going to use a relay to energize the smoke unit, it'll be an MTH HO smoke unit so it fits.

I have 6 Plymouths John. You've got my attention now....🤣🤣

Bob

@Norton posted:

John, do you have a part number for the HO smoke units. Its not jumping out at me on their parts site. I know the stock Plymouth smoke unit is fairly large. TIA.

Pete, the part is out of stock as well as all the variations.  I couldn't use the Plymouth smoke unit, I need some room for the AC-DC power supply.  The stock smoke unit fills the entire hood!

@RSJB18 posted:

I have 6 Plymouths John. You've got my attention now....🤣🤣

It's sitting on my bench and I have the Blu-2200, just have to get time to stick it in there.

Thats not good. With MTH selling off their HO I guess there is little reason to make those smoke units. Maybe the new owners have them????

Pete

@gunrunnerjohn

It's sitting on my bench and I have the Blu-2200, just have to get time to stick it in there.

I have 3 engines in pieces on my bench at the moment. Don't think it will happen anytime soon but this Blumani stuff is intriguing.

I'll be following along.....

@Norton posted:

Thats not good. With MTH selling off their HO I guess there is little reason to make those smoke units. Maybe the new owners have them????

I think the new owners didn't use DCS in their product, so I don't know if they'd use this smoke unit.  I bought a couple a while back since I used my last one, I may have been buying the last ones!  Bummer, they were great for smoking caboose upgrades as well.

Sounds like time for a 3D print!  I could make the top PCB if we could print the fluid bowl.

You miss the whole point.  It's not the power I'm worried about, it's rectifying and filtering the 18VAC track power that yields over 25 volts DC exceeds the Blunami max voltage specifications.  I just want higher voltage tolerance so I can dispense with the expensive and bulky high current regulation and just use a bridge rectifier and filter cap.

John, You have the attention of the S gauge community, S gauge GPs and the likes a short on space in the shells.

Ray