Beginning Problems

[roketrhino900]

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

[Max]

Re: Beginning Problems

Im 80% sure you need a T for the pvr
And you need the pvr before the valve (100% sure of that!)

[Laser]

Re: Beginning Problems

you need the PRV and the dump valve before the solenoid valve

[roketrhino900]

Re: Beginning Problems

Of course I need a PRV before the valve, I should have realised that.
Thanks, I know I need a T.

[RogueTwoRobots]

Re: Beginning Problems

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.

[roketrhino900]

Re: Beginning Problems

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?

[jonny]

Re: Beginning Problems

yes

[RogueTwoRobots]

Re: Beginning Problems

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.

[roketrhino900]

Re: Beginning Problems

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

[jonny]

Re: Beginning Problems

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+

[roketrhino900]

Re: Beginning Problems

In other words,
a.Is it feasible to run GOLD 24v's on a Scorpion XL,
b.What amperage do 18-24v batterys have? I've found from 2a to 15a, does this depend on the mAh?

[razerdave]

Re: Beginning Problems

I would recommend victors because you are very unlikely to need a replacement . As for batteries, the current is the mAh ratings. You can buy 12-24v packs ranging from 800mAh to 4000mAh (0.8 amps - 4 amps for an hour). Satanix was using an 18v 3300 mAh pack of NiMH cells. It lasts me 2 fights if I'm not ragging it around, and I am running speed 900's.

[roketrhino900]

Re: Beginning Problems

OK, I'll probably have to get Victors. Better get quality now to save later. I know someone who runs a battery manufacturers, and they have a range of batteries. I'd be looking something around 18-24 volts, 5-20 amps, and a mAh of 3-4 thousand?

My concern with the Victor is it always runs 10% power at least, doesent that make robots awkward to drive?

[jonny]

Re: Beginning Problems

sigh, mah are the same as amps!

mah= milliamps/hour
Ah= Amps/hour
3.3ah pack is the same as a a 3300mah pack

[roketrhino900]

Re: Beginning Problems

Whoops, well thats one more thing I can't get wrong next time!

Does the 10% lowest output on the victor affect fights much?