Setting up an Air-Ram System

This article has been copied from an email from Ian Thewlis. Thanks Ian.

Compressor.

We opted for a petrol driven compressor rather than a generator / compressor combination.  Ours is a 5.5HP engine, a cheap import we picked up on ebay for £350 including delivery.  Spec is similar to this:  http://cgi.ebay.co.uk/PNEUTEK-8HP-KOHLER-PETROL-DRIVEN-COMPRESSOR_W0QQitemZ7628967659QQcategoryZ22662QQrdZ1QQcmdZViewItem

I can't find the details of the seller, or any of the same models.  The other option is to buy a big generator (6KVA) and an electric compressor. Leeds BMX has run a system like this for years.  This may be preferable if you get a high-voltage controller (see below) or need and electricity supply.  I would not advise using thi styp eof generator for computers though.  For practical use, I have found on both the Leeds system (110V US RAM) and our system you need the compressor to maintain pressure at around 6.5 bar, if you go for the electric option it's not a very big unit needed.

RAM.

Our Ram was built by Carl Hoggart, with some influence from Eugene (also of Harworth) I think. He built one for Harworth, Coppull and us at Bradford . Most of the parts are off-the shelf, except there is some sort of tank / expansion unit that had to be custom fabricated (pretty simple box – square tubing with plates welded over the ends).  We've spoken to Carl, but he can't find any of his original design, but would probably be willing to explain it in more detail.  Might be worth you perhaps arrange to meet him at Harworth when they do gates so you can see the ram itself.  I can't find the receipt they gave us, but the parts came in about £350 in total.  I know Pete Taylor over at Coppull knows a bit about them as well – they have an issue with ‘dirty' air over there and he is always stripping theirs to clean it.  The ram has a 300mm maximum throw and we have been able to get our gate at a nice angle and a good drop with it running it at 275mm.

CONTROLLER

This is the bit I do know about!  The controller is a Cartessa AC4 unit. http://www.cartessa.com/AGC4FLY1.htm   You can buy this as either a 115V or a 230V unit, but ram trigger voltage always matches input voltage.  As we did not want to mess with generators, and I have to say I'm not very comfy with sending mains level voltages to a metal gate with 8 kids lined up on it, so I got in touch with them and discussed the possibility of a 12v unit.  We bought just the controller and two sets of lights  http://www.cartessa.com/LITEFLY2.html (four lights without speaker), and including customs duties the final bill was about £1350 I am told.  The lights we got were LED versions – they were a prototype so we got them at the same cost.  I still haven't made my mind up yet if they are better or not.  They use less power certainly, but a normal 60AH car battery has just lasted 2 months without needing charging so I would guess that even using normal bulbs you would easily get two full days of running the gate.  Removing the transformer also lowered our shipping cost so that was another advantage of the 12v system.  The guy to talk to over there is Darryl, you can reach him by email at cartessa@fuse.net .  he is very helpful, and from placing the order to us having the unit in our hands was only about 17 days – and that included the easter break!

MAKING IT ALL WORK

Once you spend all your money on the above bits, very little else is needed.  For the sound I got a couple of car rear-shelf pod speakers.  I got some rated at 40W, but I think 10-20W would have been better.

For the airline – a standard PCL quick release is fine for the Ram end, but on the compressor end you need a ISO-A type hydraulic connection, like this http://cgi.ebay.co.uk/1-4-BSP-ISO-A-HYDRAULIC-QUICK-RELEASE-COUPLING_W0QQitemZ7561854149QQcategoryZ48718QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Reason being these have valves in, which stops Gate-Creep when some of the bigger riders all rack up behind it (one of the things that effects gate timing).

Electrically, I used a length of 2-core flex to connect the controller to the Ram, Darryl sends the plug you need to connect to the controller.  If you go for two sets of lights and need to run the cable round or over the start hill you will need an extension lead.  The lights use cinch-jones type P300 series 6pin connectors, and they cannot be bought in this country.  If you're going to need them – I would arrange with Darryl to send you a male and female pair over. With the order.  They can be bought through RS components for about £4 each, but they are drop shipped from the US and come with a £10 surcharge so the two plugs cost me £20!!  I have used standard 6-core alarm wire for the extension cable and this is working fine.

The only other thing needed is a car battery!