3 amp throttle

I use variacs and a stepdown transformer.  On the output I have a bridge rectifier, a giant electrolytic capacitor, and a DPDT switch.  I have circuit breakers on both ends.  Last one I built was a long time ago, but it cost about twenty bucks and routinely handles five amps.  The secret is to use the variac first, then an inexpensive but potent stepdown.  That keeps the variac small and relatively inexpensive.

I can't help you with a cheap to build one.   There are some old Kalmbach books that have plans for some throttles.

My recommendation is to buy a bottom of the line GML throttle.   They are all rated at 3 amps.    I listed a link to their website below.    I used their throttles for years before I went to DCC and they worked great for me.   

http://www.thegmlenterprises.com/index.html

AMEN,

I am using the same and is awesome!

AG.

At that price you probably cannot build even a simple one for less.  I agree.

I am a 2 rail O scaler.  I just ordered a 3 amp pulse width modulation throttle with walkaround/memory for $72 .  I have been using PWM for several years and found it better than proprotioate voltage which most systems use.  I should receive it any day.  The person that makes these is in Canada,  but he returned my call and spent 45 minutes talking about controling trains.  Here is the web   http://www3.sympatico.ca/kstapleton3/821.HTM  If you want to know how well it works for me, email to astarr78@msn.com

My only concern when I bought the GML was the most PWM make the motor humming at low speeds, but GML is offering 30 money back and 5 years warranty so if someone is offering that , is just because he knows what he is doing....my home made pwm was working good but its high frequency buzz (humming) drove me crazy.

GML has momentum and brake...agree is more expensive but have a great customer support and warranty.

Andre.