Electrical Team Prep

[shadowraze]

My school is just starting a new FIRST Robotics Team. How can we prepare for making an electrical subteam and what kind of knowledge should the leader be prepared with.

[ttldomination]

Well. Oddly enough, you come at a strange and new time. The FRC program is undergoing a brain change. All of the electronics are new.

I would suggest a good way would be to go to the National Instruments website and try and get familiarized with the cRyo.

[Akash Rastogi]

Check out WPI's resources page about the cRIO as well.

Welcome to FRC

[Al Skierkiewicz]

I would start making a wish list of tools. You will need all the standard stuff, pliers, cutters, wire strippers, screwdrivers (both flavors). I would add to that a good digital VOM like a Fluke, big wire cutters for the #6 wire, and a soldering iron. If you can buy two, then get a 50 watt and 25 watt with interchangeable tips. #6 solders better with the 50 watt but is not needed for most applications. A good crimper for solderless connectors is a must as well. There is going to be a lot more for electrical teams to do this year. You might also search the forums for another thread about tool selcection. There were some great suggestions in other old threads.

[dtengineering]

You might want to check out last year's rules. The rules change from year to year... but not so much that reading the old rules won't help understand the new ones.

You will want to know something about the batteries, speed controllers and motors in the Kit of Parts. You will find some information here and some great seminars and lectures both recorded and in powerpoint format here.

Here's one that Al, who posted above, did. You could do far, far worse than to take advice from Al!

Jason

[Miner]

Make sure that not only the leader of the subteam, but everyone on the team is familliar with how you guys plan to do things. If the head honcho is not there, you don't want people not knowing what to do.

You could even do a training session just with the basics that everyone else in this thread talked about.

[Protronie]

I would also add that before build season you hold a soldiering clinic for the sub team and everyone learn how to properly solder wires and terminals.
Also a crimping class on how to make a good crimp and which terminals are best for which applications.

-p

[R.C.]

Originally Posted by Protronie

I would also add that before build season you hold a soldiering clinic for the sub team and everyone learn how to properly solder wires and terminals.
Also a crimping class on how to make a good crimp and which terminals are best for which applications.

-p

I can't stress this enough, making sure all the connections are good and this will save you time in debugging the robot during build and in comps.

[EricVanWyk]

Originally Posted by Protronie

I would also add that before build season you hold a soldiering clinic for the sub team and everyone learn how to properly solder wires and terminals.
Also a crimping class on how to make a good crimp and which terminals are best for which applications.

-p

More important than learning how to crimp well is learning to check that a crimp or connection is good. If everyone reflexively tug tests the connections, a bad one won't go undetected for long.

[amarill]

I may be going off topic a bit, but make sure your team gets in the habit of labeling all of your cables. It comes in real handy when you take off some parts and put them back later on. A label-maker is useful for this. Also just getting hand-written labels are all right, as long as it is legible.

[BrentJ]

Even just practice at stripping wire may save you time and money. Until you are use to it you can land up damaging the conductors by cutting in to deep.

If you have a car audio place nearby you might be able to get some off cuts to practice on. Those high powered car audio systems can use #6 and even #4 gauge wire. If you can afford the crimp terminals to spare then this would be good practice as others have suggested.

[Arthur S]

Make sure you have a safety test ready, to make sure nobody gets hurt.

[DonRotolo]

Did anyone mention crimping? Yes, it's that important. Find and buy a ratcher-type crimper for solderless terminals, it should cost around $50, and take all the non-ratcheting type and throw them away.

Tools, like Al mentioned.

Get some wire of different sizes. Get electronic type wire - stranded with relatively fine strands, stay AWAY form electrical (house wiring - THHN, THHW, etc) type of wire, it is way too stiff. #20 for sensors, #14 for light power, #12 or #10 for big motors, red and black at least.

Practice wiring stuff with crimp terminals and screw-type barrier blocks , some switches and light bulbs or motors and batteries.

Learn why you want the thickest wire you can get (within weight limits) for high-current applications.

As someone mentioned, read last year's rules and electrical guide.

Look at some photos of neatly wired robots. Or go to an off-season competition and look. Ask a lot of questions too.

Don

NOTE: The links are examples, DigiKey is not the least expensive supplier around.

[Kevin Sevcik]

At this point I think I'll start my campaign for teams moving to wire ferrules for the power distribution board. I know they boldly declare that the WAGO terminal blocks require no crimping or soldering, but I am not prepared to believe them. Using stranded wire with this style of connection make it possible to birdcage the wire as you're inserting it, leaving bare strands hanging out, waiting to short something. Especially if you're constantly shuffling wires around or are in a hurry. Under ideal assembly conditions where you technician is very practiced, etc. I'm certain this is a very rare occurrence. But conditions in FIRST pits are far from ideal, and our student technicians will not be terribly well practiced next year. So wire ferrules are the answer. They crimp onto the ends of stripped, stranded wire, turning it into a solid piece of wire that won't birdcage on you. Pin terminals are a similar option, using a standard ratcheting crimper.

Probably I'm being completely paranoid, but having my students use ferrules will give me just a little more peace of mind.

[EricVanWyk]

Originally Posted by Kevin Sevcik

At this point I think I'll start my campaign for teams moving to wire ferrules for the power distribution board. I know they boldly declare that the WAGO terminal blocks require no crimping or soldering, but I am not prepared to believe them. Using stranded wire with this style of connection make it possible to birdcage the wire as you're inserting it, leaving bare strands hanging out, waiting to short something. Especially if you're constantly shuffling wires around or are in a hurry. Under ideal assembly conditions where you technician is very practiced, etc. I'm certain this is a very rare occurrence. But conditions in FIRST pits are far from ideal, and our student technicians will not be terribly well practiced next year. So wire ferrules are the answer. They crimp onto the ends of stripped, stranded wire, turning it into a solid piece of wire that won't birdcage on you. Pin terminals are a similar option, using a standard ratcheting crimper.

Probably I'm being completely paranoid, but having my students use ferrules will give me just a little more peace of mind.

I am 98% sure that the Wagos on the PD are not designed to accept ferrules.

I am 100% sure that the Wagos on the PD are not designed to accept tinned wires. Tinning the wires will result in a very poor connection.

Simply strip the wires and insert. The cage-clamp works best when it can push the strands a bit to grip multiple surfaces. Using a ferrule reduces the contact area.