andrewganschow Posted January 30, 2016 Posted January 30, 2016 I just bought a mini air pump today and an extension wire with the intention of splicing the pump to the wire. I wanted to know which wires on a PF cable carry current, and which carry signal for RC controls. I know there are two wires to carry current and two to carry signal, I’m just not sure which wires do what. Thank you in advance for the help. Quote
John Daniels Posted January 30, 2016 Posted January 30, 2016 I don't know off hand, but it is easy enough to figure out with a voltage meter on ohms setting and any pf motor lead. Quote
goggel Posted January 30, 2016 Posted January 30, 2016 (edited) http://www.philohome.com/pf/pf.htm => Edited January 30, 2016 by goggel Quote
andrewganschow Posted January 31, 2016 Author Posted January 31, 2016 http://www.philohome.com/pf/pf.htm => thank you for this image, i forgot about philohome. Quote
Brickthus Posted January 31, 2016 Posted January 31, 2016 What is the power of the pump? It might be too much for the LEGO PF system. I used to use a small car tyre air compressor, nominally 12V, but it needed 6 Amps to start and 4 Amps steady current when driving a pneumatic model through the football inflation attachment. I got a 5-Amp mains-to-12V supply for it but even that wasn't enough. After I broke that one I got a quiet mains compressor that has a 9-litre air receiver. The air receiver is useful because the compressor has to run only 40% of the time. It has a fridge motor. It needed a hose and a tyre-inflator tool to interface with the car tyre football attachment but those parts are relatively cheap. There is a range of quiet compressors alongside the noisy ones. The alternative pure LEGO solution is to make a module of a few mini compressor cylinders on a crankshaft from a motor and make a few of those. I've tried up to 16 compressor cylinders from 2 5292 motors; it needed a big power supply! It is said that, in a workshop, compressed air costs 10x as much as electricity. This is partly because of the inefficiencies of it as a drive method. It means you might need up to 10x the electrical power to drive a pneumatic model with mechanical power equivalent to a PF electric model. Mark Quote
andrewganschow Posted January 31, 2016 Author Posted January 31, 2016 The pump only requires .3 amps. So I'm pretty sure it'll run off of the PF BB. Quote
andrewganschow Posted January 31, 2016 Author Posted January 31, 2016 you get the one that I got? :) I ordered pump model kpm27h, I think yours was kpm27c. Shouldn't be any major difference. Quote
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