Liebherr LTM1800 scale 1/24

[Southgate]

If you go back to my crane's history, you'll see I had built my controls into an MRC power packj. It has transistorized throttle. A transistor controls VOLTAGE, whereas a mechanical resistor (rheostat. if it's variable) limits CURRENT. The prob with that is if the winches use a very small amount of current, the rheostat doesnt limit it enough, or do so consistently under varying loads.

A transistor control is really easy to make, and inexpensive. I have a box of stuff, enough to experiment with so I can go make a test circuit and give ya a rundown on how to build one up for your crane.

[Southgate]

Hey, Kerst. I finally got some time to sit down and play with electronics. The question now is, do you want to set up separate speed controls for each function? Or you could set up one speed control for the carrier and separate speeds for each function of the upper. Can do anything, really. I'd recommend at least each drum has it's own speed control. That way you can walk the hook when booming up, etc.

Each speed control will require a 25K ohm linear taper potentiometer, and a 1000 ohm resistor, and a TIP 120 transistor. You obviousely know how to wire DPDT switches for direction. Adding the speed controls is pretty easy.

I can draw up the schematic for just the speed controllers and let you adapt them, or i can draw it up for the whole complete power pack.

Pot:
http://www.mouser.com/ProductDetail/...tEa96VlWu4c%3d

Transistor:
http://www.mouser.com/ProductDetail/...FOxXz1dSDIw%3d

Resistors
http://www.mouser.com/ProductDetail/...52bdlQPAamo%3d

I found this source online, but I recon you probably have well stocked electronics stores there in NY. The pots will probably be the hardest to find, the transistors and resistors are really common items.

[kerst]

Originally Posted by Southgate

Hey, Kerst. I finally got some time to sit down and play with electronics. The question now is, do you want to set up separate speed controls for each function? Or you could set up one speed control for the carrier and separate speeds for each function of the upper. Can do anything, really. I'd recommend at least each drum has it's own speed control. That way you can walk the hook when booming up, etc.

Each speed control will require a 25K ohm linear taper potentiometer, and a 1000 ohm resistor, and a TIP 120 transistor. You obviousely know how to wire DPDT switches for direction. Adding the speed controls is pretty easy.

I can draw up the schematic for just the speed controllers and let you adapt them, or i can draw it up for the whole complete power pack.

Pot:
http://www.mouser.com/ProductDetail/...tEa96VlWu4c%3d

Transistor:
http://www.mouser.com/ProductDetail/...FOxXz1dSDIw%3d

Resistors
http://www.mouser.com/ProductDetail/...52bdlQPAamo%3d

I found this source online, but I recon you probably have well stocked electronics stores there in NY. The pots will probably be the hardest to find, the transistors and resistors are really common items.

Thanks a lot for all this info! It is very helpful!
I found a used MRC power pack on eBay and i am going to experiment with that first.
At the moment I am struggling with the slip rings. One of the circuits is not working and so I took it all apart and am considering to rebuilt the whole thing and make it more dependable. But I will be away for the Holidays so it going to be January before I get to it.

kerst