Problems With The Power Distribution Block

[Steve W]

Everyone knew about this issue a while ago. A little Loctite will fix the problem.

[Tom Bottiglieri]

Originally Posted by Steve W

Everyone knew about this issue a while ago. A little Loctite will fix the problem.

Everyone? I'm pretty sure I didnt. And what about the rooks who don't even know what Loctite is?

[sanddrag]

I thought loctite ate plastic, so, I didn't go for it. Is this a different type of plastic that it doesn't eat?

[Greg Marra]

While we're talking about electrical stuff...

I am a big fan of the 2005 Power Distribution Block Thing made by IFI. I would love to see them return to bring simplicity back to robots' electrical systems. I helped wire two rookie robots in the pits at Boston on Thursday, and having that single block would have made things easier, and simpler for the rookie teams to understand.

[RoyalRobo1070]

Our main problem with it was one that was already pointed out: that the wires continued to slip out, as tightly as I or any other member or mentor screwed the screw in. If FIRST intends to continue with this power distribution block, I would suggest that they give us tips on how to keep those wires in.

[mtaman02]

Originally Posted by Greg Marra

While we're talking about electrical stuff...

I am a big fan of the 2005 Power Distribution Block Thing made by IFI. I would love to see them return to bring simplicity back to robots' electrical systems.

I inquired about the Power Distribution block at the NYC Regional and if it will it ever make a comeback the answer coming from the horses mouth (IFI) was most probably not due to the loss of money in making the product (not enough buying the product retail wise) they do agree that it was a well crafted product that made wiring a robot simple it just cost too much to manufacture it and have no one buy it.

And I know there are plenty other threads concerning this but while I already went off the topic already for all those who are wondering if the RC will change - Also coming from the horses mouth (IFI) more than likely......... not. They are happy with its current size and dimensions and why change something that works perfectly. However when ever the ancient DB9 Port is completely extinct then start looking for a new RC configuration but until then don't hold your breath =).

While Loctite is a good answer to keeping almost any screw in place I would not use a whole lot of it b/c like many have said it will need to be taken apart someday. I'm pretty sure they're other solutions out there. Maybe instead of using Loctite do some test with some crazy glue. While it's not strong enough as loctite it should get the job done and be able to be undone with just a little bit of heat.

[allen_d]

Originally Posted by Steve W

Everyone knew about this issue a while ago. A little Loctite will fix the problem.

Do they make a dip tank full of loctite that we can submerge our whole robot in?

I was not aware of this problem. I don't recall this being in any of the team updates.

I get a little concerned using loctite for this application. Even though we use blue loctite... we someday might need to take this apart!

[Daniel_LaFleur]

Originally Posted by Steve W

Everyone knew about this issue a while ago. A little Loctite will fix the problem.

First off, you should avoid using absolutes like "everyone knew", because, invariably, someone does not know.

Secondly, be very careful about reccomending loctite. Know your application and the type of loctite so that you can guage the reaction. Test on a sample (NOT ON THE ROBOT) to ensure compatability.

*note* I believe that Loctite is a good idea for this application, but please make sure that the type of loctite you use is compatable with the plastics and vynal wire coverings.

[Pavan Dave]

At Bayou, we checked our wires on and we ended up putting in some Loctite. I was against it, but after a mentor showed me how loose some of the wires were I said anything was better than nothing, and so we gave it a go. Well, none of the wires popped out to my knowledge and the drive team didn't have to tighten them after we put in the Loctite so I was satisfied. It works...but I'll get to do a better electrical inspection come Thursday at Lone Star and be even more sure!

Do I see it as necessary? No, but FIRST has their reasons I assume and now I know about ferrules and have all summer to think of new ways to keep wires in! Make this your off season project if you don't have one and than you won't have to worry about how to make wires stay in tight next year.

Pavan.

[Danny Diaz]

Originally Posted by Pavan

At Bayou, we checked our wires on and we ended up putting in some Loctite. I was against it, but after a mentor showed me how loose some of the wires were I said anything was better than nothing, and so we gave it a go. Well, none of the wires popped out to my knowledge and the drive team didn't have to tighten them after we put in the Loctite so I was satisfied. It works...but I'll get to do a better electrical inspection come Thursday at Lone Star and be even more sure!

I'll see about getting you a, "But it works on our robot!" sticker. We've had mountains of problems with wires coming loose during the build season, so we've instituted wire tightening/inspection specifically for the block in our pre and post match checklist.

-Danny

[Hieb]

I know that some manufacturers of similar power distribution blocks (not sure about Rockwell--I haven't spent enough time looking) have spring loaded connectors that may be more suitable for our applications. At least that way the vibration wouldn't loosen the screws and let the wires fall out.

[MrForbes]

The spec sheet for the terminal blocks suggests tightening the screws that hold the wires in, to 17 to 35 lb-in torque. That's a lot of torque to apply with a slot screwdriver! Maybe what's needed is to make sure someone with strong hands tightens the connections.

Also double check the wires are stripped the minimum 5/8" length.

Having a checklist to double check the tightness of the screws before competition, is a good idea.

[Al Skierkiewicz]

Originally Posted by Hieb

I know that some manufacturers of similar power distribution blocks (not sure about Rockwell--I haven't spent enough time looking) have spring loaded connectors that may be more suitable for our applications. At least that way the vibration wouldn't loosen the screws and let the wires fall out.

Rockwell also has a line of spring loaded blocks to be used only for solid wire. Never use solid wire on moving devices, they will fatique and fail.

[Alan Anderson]

Originally Posted by Hieb

I know that some manufacturers of similar power distribution blocks (not sure about Rockwell--I haven't spent enough time looking) have spring loaded connectors that may be more suitable for our applications. At least that way the vibration wouldn't loosen the screws and let the wires fall out.

The problem isn't usually with the screws themselves loosening. It's almost always because the stranded copper wire deforms and is no longer held tightly. This can happen not only with the Rockwell parts, but with the 40-amp fuse block as well.

Make tightening the electrical connections part of your standard preventive maintenance and pre-match checks, just like keeping proper chain tension or making sure the pneumatic release valve is closed.

[eugenebrooks]

I am not enamored with the rockwell power distribution block.
The positive end of the block is completely redundant, one can
simply route the positive wire through the max-fuse block to
the panel for smaller fuses and be done with it. We can do
a much lower resistance job for the ground returns with the
ground lug from 2004 than we could ever get from the power
distribution block.

Loctite should not be used on electrical connections, it is not
a conductor. There is no substitute for proper torque on all
of the electrical screws, and proper stress relief for the wires.

The terminal block does need to be tightened to specifications.
If you don't have a suitable torque screwdriver, you can do quite
well with a wrench attached to a hex drive screw driver, and a
small "fishing scale."

We have not had problems with bare wire in the power distribution block,
but if we have to use this distribution block next year we will certainly
use the ferrules.

Eugene