SCR Throttles

leon1

New Member
I am trying to find the article on SCR throttles in the Model Railroader June 1977 magizine. I would appreciate any help or suggestions
 

woodone

Member
Wow! that is very old tech. Any reason you are looking for the information? :confused: I built one a long time ago, Peter Thorne design, from a book, Electronic Projects for Model Railroaders . About 1982 - I never did get it to work??:curse: I do have MR books back to 1976, any Idea what month? I would have to dig it out as books are packed away for a move.:eek:
With all the new stuff out there, you could find something a little better and such.
No DCC? :twisted:
 

doctorwayne

Active Member
Hi leon1, and :welcome1: to the Gauge. I'm glad that you brought up this topic, as I was unaware of this article. I went and checked my back issues and found the proper issue. I'll be sending you a pm regarding this, as the magazines have been promised to a friend.

Wayne
 

JR&Son

Member
MX033 PWM DC Motor Speed Controller

The above is not an SCR, its a MOSFET
Works VERY well though
They make a cheaper version but it whines horribly!
This one is good to 15 amps.
I loaded one to more than 10 amps and it barely warmed up
Both of mine needed minor repairs on arrival
The 1st one, had bad solder joints at the speed pot
The other one was missing a screw on the heat sink
5 mins each to repair, versus a 5 year old, not very happy.
Thats why I did not bother to send them back

JR&SON
 

leon1

New Member
Wow! that is very old tech. Any reason you are looking for the information? :confused: I built one a long time ago, Peter Thorne design, from a book, Electronic Projects for Model Railroaders . About 1982 - I never did get it to work??:curse: I do have MR books back to 1976, any Idea what month? I would have to dig it out as books are packed away for a move.:eek:
With all the new stuff out there, you could find something a little better and such.
No DCC? :twisted:[/quote Hi Woodone; You said it "that is very old tech". I had better luck when I built my SCR Throttle and it is still working after twenty some odd years. I have been using it for my Christmas layouts for I haven't had the time or space for a permanent model RR. Needless to say that I am now partially retired and have found the space and possibly the time to really get back into the hobby which I love. When I built this unit I didn't make any copies of the article and the parts list and the scematic page became partially unreadable. This is the reason for my request for help! I appreciate your interest and if you find the time please send me a copy of this article. It appears in the June, 1977 issue of the Model Railroader page 70.

I Thank you again;

leon1sign1
 

woodone

Member
Leon1,
Let me see if i can put my hands on that copy,
Like I said I have my MR books boxed up for a move. They are still in the house, so I will take a look- let you know.
 

doctorwayne

Active Member
MX033 PWM DC Motor Speed Controller

The above is not an SCR, its a MOSFET
Works VERY well though
They make a cheaper version but it whines horribly!
This one is good to 15 amps.
I loaded one to more than 10 amps and it barely warmed up
Both of mine needed minor repairs on arrival
The 1st one, had bad solder joints at the speed pot
The other one was missing a screw on the heat sink
5 mins each to repair, versus a 5 year old, not very happy.
Thats why I did not bother to send them back

JR&SON

I attempted to buy a pulse width modulating throttle from a guy nearby who was building them, but got no reply to my e-mails. I was told at the LHS that they haven't seen him for a while, so that one seems to be a dead-end.
This sounds like it could be a good alternative to an SCR, which gives excellent low-speed control but doesn't have the capacity to run heavy double-headed trains on steep grades. Trains simply slow and die, even though the input is 16 volts AC.

Wayne
 
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