Maybe I am the one who was mentioned on the OGR Forum. I have repaired several PowerMasters, some for myself and some for others. Please contact me if you would like me to repair your unit.
Dale Manquen
dmanquen@msn.com
www.manquen.net
One of the design problems with the PowerMaster is that the short circuit sensing only works on one half of the 60 Hertz AC cycle. The current sensor measures the current on only half the cycle, but it kills the power for one full cycle. I believe that the problem is that the current during a short can be ‘infinite’ during the first unmeasured half cycle - before the current sensor ever knows there is a problem - and the FETs can be damaged instantly by this large current.
Most fuses and circuit breakers are WAY too slow to be of any useful protection with this very quick problem. We are talking about 8 thousandths of a second here.
[:)] Dale,
Where have you been! Unfortunately, I trashed the first Powermaster, and the second is going back to Lionel tomorrow.
I am not an electrician, but I followed your description of the problem somewhat. Your last sentence forms the basis for my ongoing concerns with TMCC. If I am cooking these Powermasters within 35 minutes of receiving them, then what can prevent me from doing this over and over again? I took the suggestion of a few on this thread and put a single channel circuit breakersin my shopping cart from Scott’s Odds n Ends and now I am not sure what to do. Of greater concern is why everyone does not have this problem or is it something in my own setup and wiring. Any suggestions on a fast blow fuse or circuit breaker that might work? Why aren’t all Powermasters frying if these have inadeqate protection as you suggest.
Good points RedCaboose. Why haven’t I fried mine? I have had derailments that cut off the power.
Good Morning
Its funny this topic is still hanging in there. I bought a 135W Powerhouse and a135w Powermaster on ebay for $36 and some change. I was amazed at how much power the 135W brick seems to have. There is very little to no voltage drop no matter how much load I put on it so far. But back to the PM-1, The one I got on ebay(well the second one)was good which amazed me. But I was here running tonite with the one I repaired and experienced a derailment and I hit the halt button and it only dropped down to 11v. I got this sick feeling knowing what that ment. Anyway so I fried the one I fixed, Thank god for the extra that I just bought!!! My cure for this problem is going to be a TPC 400. Lionel must be making a bunch of money selling replacement PM-1s to an unimformed public.
Dale is absolutely correct, the voltage spike takes place within milliseconds and the voltage generated in AC circuits during a short can be astronomical. Solid state componants don’t stand a chance.
Call me Mr. Spike Suppressor. [:D][8D][:D]
Spike suppression circuitry could save the equipment in the event of a derailment. Even with a TPC400 instead of a PM-1.
Tony
Little Pig,
Does the TPC 400 have a better circuit breaker? What about a ZW? How does that compare? I am considering the variable voltage ability of the ZW since I have a shelf layout and I am nervous about letting my kids run it with 18 volts of power running through it. Does that make sense?
HI Red
I have no idea what kind of circuit protection the TPC400 has. I would think there are a lot more qualified people around here to answer that question then me. I’ve been collecting for about 17 years but I just built my first table for a layout. So I’m learning as I go here.I certainly can understand your apprehension about letting your kids alone with full power applied to the track. It’s something I’m just starting to get comfortable with myself. I have this thought that soon as I turn my back the train is going to take off 1000 MPH and launch off the end of the table. LOL so far it hasn’t happened to me or anyone else that I know of So I think its safe!!
I am a firm believer that if someone sticks their hand in the fire and tells me its hot I’m not going to try to prove them wrong. If multiple people say surge protection between the track and PM-1 or TPC 400, whichever the case may be is the ticket to componant protection, Then thats what I will do also. Good Luck and have fun.
Jim B.