What do your teams use for electrical connectors? We were a rookie team this year and had a lot of trouble with connectors falling apart or being connected incorrectly. We have heard about using the Anderson power connectors for things other than the battery wire - are there smaller ones suitable for 12- or 18-gauge wire?
Anderson Power poles are available for a variety of currents and wire sizes. We have used the 45 amp connectors for many years. They require a little gentle handling when inserting #10 but are good for #12 and #14. If needed for #18, a simple foldover of the end of the #18 allows them to be perfectly crimped on that size wire. There is no substitute for the correct crimper. One is availalbe from West Mountain Radio and other sources. Use of these connectors for motors allows very rapid motor changes in the event of a failed motor. They are color coded (I think 12 colors at last count) and can be assembled so that they cannot be connected with improper polarity. We use the convention that when looking at the face of the contact (the part that mates with the opposite connector), the positive contact is inserted in the left block. We have modified a drill with Power Poles so that we can drive motors independent of the control system for testing and alignment.
The cheapest place I’ve been able to find them is powerwerx.com at about half the price of anywhere else. There is a single housing that holds two types of contacts, 30 Amp that work with 18-14 AWG and 45 Amp that work with 12-10 AWG wire
We are big fans of the Anderson mini Power Pole connectors. Lots of different sizes are available. Two vendors we have used within the pats year are listed below. I would highly recommend purchasing a special crimping tool for your Anderson connectors. PowerWerx makes a not-horribly-expensive crimper that works well.
Connex Electronics: http://www.connex-electronics.com/?url=/html/products/anderson/and_powerpole_main.html
PowerWerx: http://www.powerwerx.com/anderson-powerpoles/
PS: I should also note that our team regularly has success with purchasing parts from vendors at a special discount for non-profit organizations. Contacting vendors for special discounting as a 501(c)3 non-profit or a school can often save a lot of money!
Which connectors are you having trouble with? If it’s the crimp on terminals, used to connect wires to screw terminals or spade terminals (as used on Victors, Jaguars, Spikes) then the suggestions above probably won’t help.
But you do need to be more specific…there are several different types of electrical connectors used on FRC robots, and we can’t really tell what you’re talking about without more info.
edit: we have never added extra connectors on our robots, we have enough trouble with the simple things…like making good, tight, reliable connections from the power panel to the speed controllers, and from the speed controllers to the motors. Adding Anderson (or other) connectors in the circuit is kind of a luxury, so you can take things apart more quickly if needed. We’ve never had a need for them, as we don’t need to remove motors very often.
I’ve had great luck with Powerpoles for wire to wire connections. Powerwerx is a great vendor. I’m a ham and I use these connections for all my radios that run on 12 volts. The secret is the crimp, use the right tool (and the one from Powerwerx is fine) and you are good to go. The nice thing is they come in multiple colors so you can color code if you need to. You can even find panel / chassis mount powerpoles to feed through panels.
For attachment to Jags, Spikes (things with screw terminals) we use hook or ring connectors. If it will need to come off in pit change or there is danger of swarf use the hook connector. Otherwise use ring connectors. (Hook connectors can be created by cutting the side out of a ring (hold the connector cable end down, cut away from 2-4 o’clock) Use the right size ring for both the screw and the wire.
We follow Al and squirrel, the best connections are fewer connections. We only use connections when needed. If we have wires that are too short we remake them rather than adding connections.
Not, to make this thread overly complicated but, it’s important to not use ring style connectors on the Jaguar motor controllers.
The screws for the (+/-) In and the (+/-) Motor connections should not be fully removed. These are special “captive terminal screws” and when fully removed, or is the threads are crossed it can leave small metal fragments to roam about inside the jaguar leading to possible failure.
I’m not sure, but I don’t think that the captive terminal screws issue applies to the black jaguars, but of course cross-threading still can be an issue.
MDL-BDC FA Report (2009 Season) Page 8
Like Foster suggested, hooks are a pretty cool alternative to rings. You can also buy premade hooks, and you never have to go find the stupid screw you took out and misplaced when trying to get a ring terminal on…
Andersons are absolutely worth it, but you really do need to bite the bullet and buy the best crimp tool you can. It made me sick to spend the money on the nice ratcheting one but it’s been worth every penny.
Andersons can be a huge reliability improvement for your electrical connections. The way they are made they have a number of nice feature:
- When putting them together, the contacts “wipe” each other off giving a cleaner surface
- They are unisex - so you don’t have to manage two sets of inventory for male and female
- Connectors “dove-tail” together allowing you to make custom wire groupings, and have less wire wrangling to do
- The metal contacts inside the connectors are “springy” so when they are put together they exert a positive force towards the other contact making a more robust connection
The color coding is also great to have. If you keep up with it, you can easily identify when motor you’re unplugging (even in a really tight space) and it’s very hard for someone in a hurry accidentally plug something in backwards.
Adding Andersons to the ends of all your motors (before the wires run too far into bundles) makes for very very easy and painless motor and motor assembly swaps, but adding any connector just because your wire is too short is probably just lazy.
As long as you have a good crimper the only other thing to watch out for is if you reuse your your connectors or change the housing color, the contact can get bent slightly and is will not lock over the metal tongue in the housing. The result is that the contact will try to back out of the housing when mated and is a bit hard to see if you’re not looking for it.
If you’re having problems with the basic connectors that in the Kit of Parts, Anderson connectors aren’t going to help you much.
Learning how to correctly crimp, then solder, then heat shrink those wires is going to be your best bet.
Step 1 is to buy a decent crimp. They’re only about $20.
Step two is to teach your electrical team the pull test. Crimp, then pull. Not gently either. If you can pull it apart after you’ve crimped it, you aren’t doing it right.
As another added level of security, solder the wire. Be careful if you have female terminals: you can accidentally fill them with solder so the male terminal can’t be inserted.
Finally, heat shrink them. We use heat shrink with internal glue to add one last final layer of security.
Crimping PWM wires is another story. There are both right and wrong ways to crimp wires - there are many useful guides on the net:
Here’s a equivalent-to-PWM guide:
This is just one example:
http://www.tpub.com/neets/book4/12f.htm
The electronics on a robot are something that deserves great respect.
I imagine on many teams, the electronics people are just told to “wire the robot”, and use what is on hand.
If you want a truly reliable robot, with zero electrical failures in a season (very possible), you need to get them decent tools, decent supplies, space for electronics in design, and the time to wire the robot. They also need to get familiar with all the tools and connections preseason to know them well.
What Adam ^^ said.
For crimp connectors, get a ratcheting crimper. I paid less than $35 for mine.
Then use the right size connectors. They come in different sizes for different wire gauges, AND different sizes for the terminal end (fork, spade, hook, etc) screw size (like #6 of #8, for #6 screws or #8 screws, and so on).
Then use GOOD quality connectors, with nylon insulators. Cheap no-name connectors will not work as well as name-brand ones, honest. They’re still inexpensive.
Then get good wire. Not at Home Depot or Lowes (or Radio Shack). Go to McMaster or DigiKey or Jameco (and others) and buy good automotive-grade (can handle 60C or better) wire. Buy a few sizes (10 to 22 AWG) in Black and Red (and white for the 22 Gauge), a few hundred feet of each (maybe only 100 feet of the biggest stuff, it gets expensive).
For other connectors (like PWM wires or those smaller Powerpoles), you must also be certain to get the CORRECT crimper. Search ChiefDelphi for info.
Regarding solder: It is a wonderful thing, but a properly crimped connection is superior to a soldered one. Think of solder as glue, not a conductor: It holds a good connection in place, but won’t make a bad connection better. In general, you should only be crimping wires, not soldering.
Correct, the screws on Gray Jaguar (MDL-BDC) are captive and will leave behind small metal fragments when backed out completely, but this issue was addressed on Black Jaguar. Black Jags do not have captive screws.
My team still uses spade terminals for the reason you mentioned above, lost screws. It is also bad if you accidentally put the colored screws back in the wrong place (red in negative terminal, for example)… Knowing how my brain works, matching colors is easier than actually thinking about what I’m doing! (thanks Candyland?)
I’ve heard the gripe about spade terminals spreading under the screw when it is tightened. Something that I’ve noticed is that the standard hardware stores do not sell spade terminals designed for #6 screws (the screw size on the Jaguars and Victors), they are usually for #8 screws. If you can get your hands on #6 spades (69145K918 at McMaster), you’ll find that they don’t spread out under the screws pressure, and you can actually get a tight fit.
I haven’t played with the flanged spades or the hook terminals (except making my own from rings in a pinch). I imagine they add quite a bit more security.
-David
You might also try some of these…
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=920024-07-ND
They have a captive style that keeps them in place while you tighten the hardware and many have a formed locking surface that keeps hardware tight with vibration. The yellow indicates wire size of #10-#12 AWG. Often these are available at hardware stores and home centers. Used with a ratcheting crimper they are fairly reliable.
Hi all, I would second, third, and well, whatever, the power pole idea.
Our team uses them on all motors, and sensors. We used CAN this year and that worked well too.
The idea is that one only has to pull a few (properly labeled so you know where they go) connectors, and the whole electrical board is removable.
This is a great thing when mechanical wants to drill, file, and other wise produce bad stuff that will short your electrical parts out.
The thing I wanted to add is to put a small drop of super glue on the dove tail just before you put them together. That works much better than pins, heat shrink or whatever to hold the connector together.
Do it right once and you will never have to redo it, well, unless software changes where that Jag connects to. lol
Mike
Mike,
The bad thing about that is needing to get them apart. Once glued you are hosed if something doesn’t work or the wire breaks. We used the Anderson clamps for a while and found that if you tywrap the wire on both sides of the connection, they do not come apart. One cut releases one side if you need to make changes while the other side is still tied down.
Instead of those Powerpoles, we use quick disconnects like these:
When crimped and used properly, they’re very easy to use. We also put these:
on our Victors (a mentor picked some up at a local electronics store; those aren’t the ones we bought, but they resemble what we used closely). Many of the Victors have spade tongue terminals on them (what Al suggested), but that was because that wiring was done early on, and we only realized the benefits of quick disconnects late in the season.
Spade tongues are useful, especially because the screw does not have to come all the way out to put it in, but what I’ve found has happened is that these terminals have popped out. The reason is that the force holding the terminal down actually pushes the tongs of the tongue apart; consequently, the terminal just pops out. It happened enough times that we went over every single Victor wired with a spade tongue and used some pliers to close the tongs that looked like were ready to pop.
Al, I think he’s referring to the small powerpoles, designed to use the roll pin to hold them together. An assembled black/red pair can be zip tied together, but what keeps red and black next to each other?
We don’t use super glue, instead some far weaker glue, just enough to gum up the dovetail so it doesn’t come apart easily.
Woe to the team that uses the metal roll pins: They WILL come out and short power to ground, these should never be used.
Don,
There is a clamp that fits over a dual Power Pole mated pair. They are black and snap over the connector block when mated. You can see the variety of them here listed as Blok-Lok…
http://www.powerwerx.com/anderson-powerpoles/accessories/
The roll pin is designed to keep the red and black pair from sliding apart during mating.
Wow Al, something new! Thanks. 
When I use PowerPoles for home stuff, I just let them stay together with friction. But gluing them doesn’t cause problems - if the contact fails, we can replace it, and if the body fails, it gets discarded.
This year we used spade connectors on our Jaguars with the Tyco tabs. It was terrific when we needed to switch out a Jaguar or move them around. We had quite a few problems with them coming off, though. Especially given the trauma of going over the bumps.
What we found was we had to be careful to bend the 12 gauge wires such that they naturally wanted to push the connectors in.
We were using normal Home Depot female spade connectors. Are there any that grip more firmly? It happened enough this season that the team is ready to try hook connectors next time.
Be aware that spade connectors come in two sizes for tab thickness, .032" and .020". If you have the wrong ones they will come apart but the correct ones usually come off hard to the point you sometimes need needle nose pliers.