@Crazy Train posted:My contribution to the Blunami conversion effort...
I bought some of the cheapo LM2596 AC-DC voltage regulator boards from Amazon to see if they could cut the mustard in a Blunami conversion. This is the device listed as an "AC/DC to DC step down converter" and rated for 2.2A.Overall, I'm not sure if the hot inductor caused the LM2596 chip to heat up or if the LM2596 chip caused the inductor to heat up. Either way, I don't want something that hot to be inside my plastic shell diesel. So, if your going to do a conversion and want to use one of those cheap regulators from the web, be sure to run the loco for a while at high current and check the temps of the regulator.
For my conversion, I'll be following the same method that Norm used. That is, mount a full bridge rectifier to the loco's metal chassis and use a large filter capacitor on the output. Also, oversizing the rectifier to one that has a large metal surface will help pull the heat out quicker. And picking one with a low forward voltage drop will reduce the heat dissipated. Lastly, I'll be putting a TVS on the AC input.
There are a lot of inexpensive buck regulators out there. Not all overheat. A 5 amp unit from Amazon can be had for 4 bucks and easily handles a 4408 Blunami. 2-3 amp Buck regulators suitable for 2200s that don’t overheat will cost more. Pololu has some that cost about 15 bucks but are very small, less than 1” square, where space is at a premium.
Pete
