Main Power Terminal Blocks?
 

I've been laying out some diagrams for the electrical on this year's robot, and the only components that I haven't been familiar with are the new terminal blocks.

These are the modular square boxes that are intended to be attached to a supplied rail.
On FIRST's supplied diagram, they are wired between the main breaker/switch and all of the breaker panels and components. I've never used terminal strips like this, I've just wired directly from the positive output on the main switch to the positive input on the component boards, and then used a separate terminal block to return on the negatives to.

So really, my question is, does anyone know if these terminal blocks have to be wired to the positive side of the circuit out of the main breaker?

Thanks.
-Kevin

Re: Main Power Terminal Blocks?
 

The power distrubution block is not required by the rules. But, if you are using more than one circuit breaker panel, it would be good wiring practice.

Re: Main Power Terminal Blocks?
 

I think it is required. See <R57>.

Re: Main Power Terminal Blocks?
 

I also intepret <R57> to mean that the power distribution blocks must be used:

The power distribution block must be directly connected to the APP connector and main
120-amp circuit breaker. No other loads may be connected to the main 120-amp circuit
breaker.

Re: Main Power Terminal Blocks?
 

I don't mean to be un-gracious, but what is the point for this new power distribution block? It is taking up a great deal more space and weight. The Maxi fuse block is designed to take like 4 or maybe even two gauge wire. The other panels have big enough lugs to take a terminal for 6 gauge wire. In the past, we would always run 6 gauge wire off the breaker to every panel. Why this intermediate thing? To me, it is like driving from Los Angeles to San Francisco by passing through Wyoming. Is there a good reason for it that I'm not seeing? If not, can we rally for a rule change so it isn't required?

Re: Main Power Terminal Blocks?
 

Okay, thanks for the info. I must have looked right over <R57> last night.

I agree though, that this seems to be less of a help than a hindrance... I'm gonna have to sketch my diagram out again, taking into account using a bit more large gauge wiring to fit this block...

Re: Main Power Terminal Blocks?
 

That is exactly what I have been trying to say. It is MUCH more weight and less practical from my knowledge.

Can a controls mentor please explain the function of a power block I do not completely understand.

Pavan.

Re: Main Power Terminal Blocks?
 

Honestly they are completely useless. From what i know what you always did is still allowed and is not a wrong way of doing it. These blocks are probably just a way for making the electronics look nicer.

Re: Main Power Terminal Blocks?
 

I beleive its leagal to use last years power distribution block (altho i havent gotten all the way through the robot section). DIN Rails do add weight but adds a nice organization to your electronics. I do agree it does seem kinda redundant, we found out we will need more negative blocks then the amount we were given and much less positive as we are just using breaker panels for all of our victors, spikes, and the RC.

Re: Main Power Terminal Blocks?
 

all the fuse panels are the exact same ones from last years, the power distribution box last year wasnt a DIN Rail but it was essentially the same thing just made of a solid block of plastic.

Last years PDB does comply with the rules for the 2007 FIRST Robotics Competition because its the same exact thing as the DIN Rail just not on a rail.

Re: Main Power Terminal Blocks?
 

Thanks guys. I stand corrected.

Re: Main Power Terminal Blocks?
 

Guys,
As much as these rail mounted blocks add weight and space, they are standard equipment in most modern electrical installations. Be sure to use the jumper accessory to connect all of the positive blocks together and all of the negative blocks together. These blocks will take #6 wire and I recommend using only #6 to feed the 40 amp Maxi block. It is best to strip back 1-1/2" of insulation and then fold over the strands, twice, so that they fill the entry hole in the Maxi block. This will give you a reliable connection that will not loosen over time.

Please watch the team updates for a change on these though. I feel there is an error in the electrical diagram as far as the negative battery side wiring is concerned. Negative lead wiring should follow the same distribution as the positive lead wiring, i.e. all black wiring should return to the DIN blocks, not a common point. Remember all current flowing out of the battery on the red wire, returns to the battery through the black wire.

Re: Main Power Terminal Blocks?
 

I take this to mean we cannot use the 2005 All-in-one Breaker Panel

And as a side note, where is the power distribution diagram? I can't seem to find it.

Re: Main Power Terminal Blocks?
 

The diagram was on the documentation area of the website. I believe the electrical rules prevent the use of last year's hardware and more importantly, the IFI breaker panel.

Re: Main Power Terminal Blocks?
 

this how you get to the power diagram.
go here:
http://www.usfirst.org/community/frc...nt.aspx?id=452
go down to Section 8 - The Robot

Re: Main Power Terminal Blocks?
 

Ah yes, thank you.

And that's what I thought. Poo, now I get to redesign the electronics box.

Re: Main Power Terminal Blocks?
 

The newly revised Tips and Guidelines is now available on the First website. As I was reviewing it, I found that the Guide shows what my belief for correct wiring of the negative lead blocks and 40 amp returns should be. Please review for your own electrical system design.

Looking for some wiring advice
 

I am wiring up our power panel with the RC controller, spikes, and victors and have a few questions:

1. What guage wire is recommended to tie the heavy duty fuse block to the victors? These have 40 A fuses so I am guessing (10 or 12 awg?)

2. What about the fan motors on the victors? I am assuming these are12v- where do most people connect the fans to for power, (fuse panel for always on or something else)?

3. I am using 14 AWG between the fuse block and the spikes, is this the correct guage to use for this?

4. I got one small bag of quick connect push on terminal with our kit but these don't seem to be enough. Is ther ea problem with using any push on lug or do they have to be from the same mfg. that provided the ones in the kit?

5. Does anyone have a recommendation of which RC module output should control which spike or victor based upn the default code?

Thanks in advance.

Re: Main Power Terminal Blocks?
 

I looked briefly at the blocks, and the center jumpers. I noticed that the center jumpers look a little bit like a fuse...although I found no mention in the AB documentation of current limits of the jumpers in my brief reading.

But I do like the power blocks, they make me feel better about offering some protection in case the small wires from the 120 amp breaker to the individual fuse panels accidently shorted. I noticed that the wiring on last years robot offered no protection for certain types of wiring problems, and I think the new distribution block could make it safer.

(I'm an ME, not an EE, so maybe someone could tell me if I'm on the right track?)

Re: Looking for some wiring advice
 

In the manual, Section 8 the Robot, Rules 87-98 will give you all the electrial specifics you are seeking.

In the default code from IFI, PWM01 is mapped to Joystick Port 1 X axis and PWM02 is mapped to Joystick Port 2 X axis. Typically they connect to the drive motor victors, but it's completely up tp you as to how you'ed like it to work

Re: Looking for some wiring advice
 

Here are my recommendations...
#10 for all motor wiring other than perhaps the Globe.
Attach the fan wires to the power input to the Victor. This way you will know if the Victor is receiving power.
Follow the wiring restrictions for wiring the Spike by what size breaker you are using.
Purchase additional push on connectors from Digikey. We use the non-insulated type since we solder all connections following crimping and then cover with heatshrink tubing.
If you take a close look at the default code, you will see that the Victor PWM outputs are mapped to certain joystick input, use the ones that are for the joystick port(s) you will use in your design, either single or dual joystick. The spike outputs are your choice except if you use the compressor which again you will have to investigate the default docs for info.

Re: Main Power Terminal Blocks?
 

Al--Do you have a recommendation for where to connect the return (black) wire from each of any additional high power Victors (driving CIMs)? The power distribution diagram does not seem to suggest where they would go.

Re: Main Power Terminal Blocks?
 

Thank you Al- that is great advice!

Re: Main Power Terminal Blocks?
 

Al-

We discovered that the blocks will take a #6 wire as well the other night. However if memory is correct a #6 wire will handle roughly 125amps. We did some research though and according to the Maxi block website the blocks are only rated for 85amps, meaning you should use only #8 wire. This is something that either a Q&A needs to be asked (Do we need to go through the Maxi block?) or teams will have to find out the hard way at their first regional (meaning the inspectors need to know).

-Mark

Re: Main Power Terminal Blocks?
 

Jim,
See my post above, the Tips and Guidelines has been revised on the First website. Use the DIN blocks to return the 40 amp branches to the negative lead.

40 AMP returns revisited
 

Al

I think the question WRT to the 40 AMP returns is that the diagram (in the power distribution diagram) shows only 3 40A returns. What if you are using 4 or more CIMs (4 2.5" and one 3")? Can the grounds be combined so that two motors share a ground terminal block or do we need to get more black blocks?

In the Guidelines 'corrected' diagram, they show only 2 40A returns, which makes it more confusing.


Deb

Re: Main Power Terminal Blocks?
 

My thinking is, I may be able to provide all service without the need for the ATC 12 or 6 breaker panels, so I need to ask, since I am uncertain.

Since we will need a 2nd Maxi-Block(total 2) because we need one more 40 AMP service(total 5) Can I use those 3 currently unused circuts on the 2nd MAXI-Block for lower amp services, for example the 20amp service for the RC, a 30amp service for a different motor on a victor, ect???

Would I also need more "Black" DIN blocks as well to now tie all those to ground?

Thanks!
Michael

Re: Main Power Terminal Blocks?
 

The DIN rail when fully assembled makes the whole block negative and the other side positive. So in effect you may connect wires to both sides for positive and or negative (see attached picture). Hope that helps

Re: Main Power Terminal Blocks?
 

So why is it in the rules that we must use these blocks?

if you look @ team 2200's wiring, i am now going to have to change it. Just so that i can run 2 power wires from the 120 amp breakers to the 2 Breaker Panels.

Do i have to use one for the negative side even tho i am just going from the battery to the one breaker panel?

- Bochek

Re: Main Power Terminal Blocks?
 

Does Anyone have the 1 – 199-DR1 din rail on hand so they could give me the slot dimensions? particularly how far apart they are

Re: Main Power Terminal Blocks?
 

Ah, yes, that clears things up.

thank you
deb

Re: Main Power Terminal Blocks?
 

Michael,
20 amp breakers will not fit into the 40 amp Maxi blocks and you need at least one 20 amp breaker for the RC.
Adam,
Unfortunately, you do need to redo the electrical on this pictured robot. I might add that you have some rather excessive lengths on the primary wiring. Every inch of wire limits the maximum current that can be delivered to your motors. If you simply move the main breaker closer to the pump and turn the Maxi block over so that the ground termination is closer to the inside of the robot you would remove almost 5 ft. of #6 wire I bet.
You will also make inspectors very happy if you could orient the Maxi block so that the breaker labels were visible. Please insulate the battery terminals before doing anything else. Thanks.

Re: Main Power Terminal Blocks?
 

One does not follow the other. Although the blocks may be rated for 85 Amps, the use of a larger wire does not cause any problems. You may safely use any wire up to the maximum for which the connector is rated (#6 you stated)

Using the largest wire possible has advantages, particularly in minimizing voltage drop due to ohmic losses. Of course, it does weigh more, so that's a disadvantage that needs to be considered.

Don

Re: Main Power Terminal Blocks?
 

Thanks Al,
I realized that myself today, when I unpacked everything and looked into the possbility and noticed immediately that the smaller breakers wouldn't fit.(In years past we used the now defunct IFI breaker panel).

So it looks like 2 maxi-blocks, and 1 atc-6 breaker for us this season.

*sigh* It's only one more pound after all. LOL!!!

Thanks again to everyone.

Re: Main Power Terminal Blocks?
 

I see that the most common recommendation for wiring the 120 A breaker, battery, terminal blocks, etc. is 6 gauge wire. Last year however, our robot's 6 gauge wire was hot at the end of every match, leading me to believe that ideally lower gauge wire would decrease the temperature increase of our wires, as well as decrease resistance and voltage drop.

I have not seen any rules saying we can't use 4 gauge, and our team likely will, but does anyone here see any electrical disadvantages and possible rule violations? (The largest factor that may persuade us not to use 4 gauge is that it doesn't fit in some of the given power supply equipment (like the new Power Terminal Strip).

Thanks in advance for the feedback =)

Re: Main Power Terminal Blocks?
 

Chaychay,
The wire guages in the robot rules are minimums as long as you stay with the breakers specified. I have not looked closely at the specs for the terminal blocks, but larger wire may not fit those blocks.
However, if your #6 was getting hot, you had a much bigger problem. Your robot was likely running near the point at which the 120 amp circuit breaker was close to trippin. This is not an auto reset breaker, once tripped you are done. Ther are other possiblities, was the #6 from the battery to connector hot or from the connector to the main circuit breaker or was all #6 hot? In order to raise the temp on all #6, you had to be running close to stall on all motors which means you were drawing well over 200-250 amps and likely was running the battery down in one match.

Re: Main Power Terminal Blocks?
 

Thanks for the feedback Mr. Skierkiewicz!

All the 6 gauge was hot, but the wire from the battery to the 120 amp breaker was the worst. After a hard match (hard on the drive motors) it would be hot enough that I'd say any hotter and the insulation would have become pudgy. (notes: we were using a 2006 battery, 6 gauge provided in kit for power distribution, running 4 CIM's on drive, 1 mini-bike on shooter, and globes/fishers for ball transport through the robot....so we were indeed drawing quite a bit of energy)

We checked our robot post-season to ensure we didn't have any loose electrical connections, (like a loose crimp head creating this abnormal current draw) and found nothing.

(I'm my journeys across the internet I found that www.robotmarketplace.com rates the Anderson Powerpole connectors we use at 50 amps. (they are blue on the the website, but the dimensions match the APP connectors that we are given. (even though we somehow get 6 gauge wire into those connectors)) - just thought that was an interesting tid-bit, I was surprised seeing as we have a 120 amp breaker right after this connector thats only rated for 50 amps.

Anyway, we'll probably be going with 4 gauge (~1000 strand), if your interested in how it works out, or any problems we had/are having along the way, feel free to PM me :) - If anyone has any special tips for working with 4 gauge, let me know, we appreciate it very very much.

Re: Main Power Terminal Blocks?
 

can some one tell me if there is a video on how to mount the power distribution block because these things are separated and it looks like there is a tray in the bottom am i missing a part?can i get a link to the instructional videos?

Re: Main Power Terminal Blocks?
 

Don't know about a video, but the drawing provided here is pretty good. The part at the bottom is called DIN Rail, and is commonly used to mount a wide variety of electrical components in industrial settings.

Re: Main Power Terminal Blocks?
 

Jay,
The Anderson connectors are rated for 50 amps but in our application, that should be OK. The electrical system with the wire size minimums, 50 amp connector, battery, and circuit breakers, is designed so that a 2.5 minute match should not raise the temperature of any component to the point of failure. If you look up a wire table for #6, you will see a similar pattern for allowable current. The wire tables are rating current or "ampacity" for the temperature rise of the wire inside a conduit (or in free air if you find a really good table) for continuos duty. 'Free air' being a higher current. Since you are heating the wire in only a few minutes, you were drawing some serious currents. This is why I suggest all teams borrow or buy a current probe or 'Amp-Clamp' to check the current on their robot. You may have a few seconds of peak currents while starting motors but current draw should smooth out to less than 100 amps while driving. Since all the wiring was hot, you were drawing very currents all the time. This could have been due to the design choices you made for speed/torque/efficiency on each motor or you could have had some binding in the drive train or simply high friction in the beraings due to weight. Teams should always check their performance against the design criteria to be sure they are running near design parameters.
A final note: The wire heating would also conduct to the main circuit breaker so that it's trip point would be far less than designed. Did you ever trip the main breaker?

Re: Main Power Terminal Blocks?
 

Mr. Skierkiewicz, I do not recall the 120 A breaker ever tripping last year, I guess we were cutting it really really close.

Seeing that much of our main power distribution equipment is rated for ~50+ Amps, would there be a noticeable advantage of upgrading some of that equipment to ratings of ~120+ Amps say in a pushing duel between two robots?

Re: Main Power Terminal Blocks?
 

There is very little you can change other than wire. If you think of this in real world terms, (and I am just guessing here) with the amount of heat generated by your robot last year, you would have been dropping a significant amount of voltage in the wiring that was getting hot. Assuming you cut little or no wire from the #6 connected to Anderson connectors and you added some additional #6 then you had a lot of series resistance. I use an easily understood term for this loss called the "wire foot". Each piece of wire has resistance that translates to a voltage drop just by current passing through it. A "wire foot" is 100 amps (approx stall current on drive motors) flowing through a #10 wire which drops about 1/10 of a volt per foot of wire. Since 1 foot of #6 is about 1/2 WF, and you were passing more than 200 amps through your #6, a quick calculation would be 2 (twice the standard current) x 0.5 WF x 6 ft of wire=0.6 volts in just the #6. Add in the other wiring and the internal resistance of the battery (11WF) and you should have been resetting the RC on a regular basis as the voltage would have easily been drooping to below the 8 volt cutout for the RC. (200 amps x 11WF=2.2 volts just in the internal resistance of the battery) By substituting #4, you would have dropped the loss in the primary wiring (battery, connector, main breaker and breaker panel) by half or 0.3 volts. You can easily pick up that much by cutting the #6 wire length in half. Remember, you have to account for all the wire, black and red in your calculations.

Re: Main Power Terminal Blocks?
 

Jay,

I agree completely with what Al has posted. You had some very serious problems in your 2006 robot for the wire to become "pudgy" after a 2 minute match. Melting insulation could cause a short circuit of your battery...

My team pushed the envelope on motor utilization in 2006. We won two regionals and Galileo division at the Nats. We burnt out 4 sets of FP motors and quite a few drive train components doing it. We used 4 small CIMs, 2 FPs, 2 large CIMs and an air compressor. Almost all were running full power and/or full speed during the majority of time in our matches... We sucked so much current from the 12V battery that the "low battery" indicator on the OI would light up (even during practice matches).

Only once did our 6 AWG wires get warm. Investigation revealed that a frame had "racked" to the point that turning that assembly by hand was impossible. We fixed the mechanical issue and the wire temps returned to normal.

By increasing the wire gauge, you are treating the symptom rather than the root cause and other components will start to fail (connectors, batteries, et cetera). Failure of these types of components can be "very interesting" (translate: scary).

You might also consider that some protective devices, like the 120A CB, may have failed closed (contacts welded shut) on your robot to allow such high wire temps to occur without tripping.

As a mentor, I would have a hard time allowing my students to operate a robot with the conditions you describe. I would very likely take the unpopular position and force my team to withdraw from the competition if the root cause could not be determined and corrected.

Let me put it another way. If the main power wires coming into my house were hot and "pudgy", I could not and would not sleep in that house.

I strongly suggest that you follow Al's advise. Get a good clamp-on DC amp meter and compare motor measurements to design specifications.

Even though it is not against the rules, in no way would I endorse going to 4 AWG wire...

Regards,

Mike

Re: Main Power Terminal Blocks?
 

Ok,
So I checked the Rockwell site for the terminal blocks supplied in the kit this year. The are listed for accepting wires from #14-#6 and are rated for 75 amps each. The spec sheet says you can double up on some guage wires (not #6) but must derate the current handling. For our purposes with the 120 amp circuit breaker, 50 amp Anderson connector and 40 amp branch circuit breakers, this seems like an good product for our use (other then weight and size). I was unable to find a spec on current handling for the jumper though. If anyone can find it I would appreciate a post on the subject.

Re: Main Power Terminal Blocks?
 

I think that's the main reason they've added this requirement. In essence, the main goal of good wiring is being able to edit it efficiently. Anyone going from FIRST to small scale electronics will want to be very familiar with efficient power bus use. And being able to find all connections to main power helps a lot while you're staring at a big jumble of wires (depending on how good your wiring is >_>).

Re: Main Power Terminal Blocks?
 

Does anyone know where to buy spare blocks (This Years).

Re: Main Power Terminal Blocks?
 

I know this thread is a little old, but I really want to confirm whether ghhs is right. Is it okay to use power distribution block from 2006 instead of the DIN rail? R27 seems to indicate that you can't. But then there's R28 having me wish I knew what COTS meant. Honestly, after four years of FIRST, I still have no idea how to understand the rules.

Re: Main Power Terminal Blocks?
 

According the robot rules you must use the DIN Rail mounter terminal blocks as shown in both the robot rules section and Tips and Guidelines.

<R57> The 12V battery, the main 120-amp circuit breaker, the power distribution block, and circuit
breaker distribution panels must be connected as shown in the 2007 Power Distribution
Diagram. In particular:
The battery must be connected to the ROBOT power system through the use of the
Anderson Power Products (APP) connector.
The APP connector must be attached to the battery with either the copper lugs provided in the FCI Burndy Bag or appropriate crimp-on lug connectors.
The battery terminals and the connecting lugs must be insulated with shrink tubing and/orelectrical tape.
The main 120-amp circuit breaker must be directly connected to the hot (+) leg of the
ROBOT-side APP connector. Only one 120 amp main circuit breaker is allowed. This
breaker must not be bypassed.
The power distribution block must be directly connected to the APP connector and main
120-amp circuit breaker. No other loads may be connected to the main 120-amp circuit breaker.
All circuit breaker distribution panels must be connected directly to the power distribution block. No intermediate connections are permitted.
The rules are also supplemented by the Tips and Guidelines and the robot wiring diagram all available on the first website here...http://www.usfirst.org/community/frc...nt.aspx?id=452