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I've got so many stupid questions, that I think I need a new thread for all of them. Thanks for helping me with them so far, everyone here is very helpful.
So far my pneumatic advise is based on this:
Tank-regulator----T-------3/2 valve-prv-ram
/////////// dump valve////////////////
Courtesy of Anttazz.
For the PRV, is it 3-way, or do you use a T before it?
Thanks in advance and for answering my previous newbie questions, George
Im 80% sure you need a T for the pvr
And you need the pvr before the valve (100% sure of that!)
you need the PRV and the dump valve before the solenoid valve
Of course I need a PRV before the valve, I should have realised that.
Thanks, I know I need a T.
I found this diagram quite useful when starting to look into dabbling with pneumatics:
[attachment=1:exbhlwzu]PneumaticDiagram2.jpg[/attachment:exbhlwzu]
And this picture from one of Calum's (calumco) build threads helped visualise it:
[attachment=0:exbhlwzu]calum_low_pressure_pneumatics.JPG[/attachment:exbhlwzu]
(I think the PRV and dump valve come off the block on top of the blue buffer tank)
Hope that helps.
The pictures really do help, the diagram more.
But why is there a second tube from the end of the ram going to the valve? Is this to help the return?
yes
Rams are either single-acting or double-acting. Single-acting sees gas fired into the bottom of the ram, pushing it out. It then uses some form of mechanical return, either a spring inside the ram or, in most roboteers' cases, bungee cord to pull down the flipper arm, thus pushing the ram back in.
Double-acting rams use gas to both extend and retract the ram. For retraction, gas is fired into the top of the ram, pushing it down, while the gas already in the ram from firing it is pushed out and exhausted into the atmosphere. This means you don't need a spring or bungee cord to bring the ram back down. But one downside is that you're effectively using almost double the gas for one flip which, if you have a limited supply, can hinder the usefulness of your weapon.
OK, I want to keep it simple so I'm keeping the single-acting cylinder. Thanks for explaining them.
I'm still looking at speedos, its between Scorpion XL's and Victor 883's. I'm on a budget of around £200 currently to finish the electronics, thats speedos, batteries, possible BEC, and battle switch, and hopefully some valves ready for the flipper.
Of course Victors are best, but it would be cheaper to get Scorpions. I'm running GOLD motors, which have a stall current of 25 amps. The Scorpion XL can do a max of 12.5 amps, for a few minutes. Is it feasible to run a pair of GOLDs on the low ampage from the scorpion?
What sort of ampage can you get from 24 v batteries? (Or are 18v's more suitable?) I've seen bike batteries on 12v with 8 amps, but 18 v with 4a, and 24v with 24a. Of course it all effects how long the battery will run for, but what sort of spec battery am I looking for?
Thanks, George
you only need 1 scorpion, they're a dual speed controller. A scorpion xxl would probably be best at around £120 with fan and enclosure delivered to your door.
for batteries i aim for 3000mah+