do we "NEED" the power distribution block

[youngWilliam14]

I'd just like to know one thing: are we allowed to cut the yellow jumpers to fit just two or three blocks? I'd love to get rid of the red and black blocks that I won't be using.

[MikeDubreuil]

Originally Posted by youngWilliam14

I'd just like to know one thing: are we allowed to cut the yellow jumpers to fit just two or three blocks? I'd love to get rid of the red and black blocks that I won't be using.

According to FIRST's answer in the Q&A, I would say yes.

[Mike Martus]

Be very careful cutting the jumpers. I would advise against it.

They sell jumpers for two blocks - I was told at a Bradley dealer, I did not order them however.

[Al Skierkiewicz]

William and Mike,
I don't think that the Q&A fully addressed the cutting of the jumper plugs. If that is allowed in the future, it must include a note to fully insulate the cut end. Quite frankly, the majority of weight is already there, and having an extra block to add functionality later would be a desirable thing. If you are using a four motor drive and 40 amp breakers, you need at least two red and three black blocks anyway.

[MikeDubreuil]

By my possibly wrong interpretation, by virtue of telling us we don't have to use all the blocks FIRST is telling us we can cut the yellow jumper. The yellow jumper will not fit if you do not cut it. I would assume the person answering the Q/A would know this. You know what they say about assuming...

I will make sure the teams I mentor add a strip of electrical tape on the metal exposed end of the jumper.

[Al Skierkiewicz]

Originally Posted by MikeDubreuil

You know what they say about assuming...

You and me...both!

[BrianBSL]

Originally Posted by Al Skierkiewicz

William and Mike,
I don't think that the Q&A fully addressed the cutting of the jumper plugs. If that is allowed in the future, it must include a note to fully insulate the cut end. Quite frankly, the majority of weight is already there, and having an extra block to add functionality later would be a desirable thing. If you are using a four motor drive and 40 amp breakers, you need at least two red and three black blocks anyway.

The instructions on assembly for the module specifically state that it can be cut: http://www2.usfirst.org/2007comp_173...Strip%20R3.pdf

15) The assembly may be shortened as desired by removing the extra terminals and cutting the DIN rail and the center jumper bar(s) to the desired length(s).

In addition, a 4 motor drive with 40A breakers, and only one 20/30A fuse block could be satisfied with 2 red and 2 black, as the same document states that you can put 2 10ga or 3 12ga wires in the same connection:

Maximum Wire Size and Max Quantity Allowed per 1492-J16xx Terminal
1 - #6 or
1 - #8 or
2 - #10 or
3 - #12 or
4 - #14 or
4 - #16

(2 connections for 4 12ga wires and 2 connections for 2 6ga wires on the black, 3 connections for 3 6ga wires on the red).

Given that these are the instructions they are providing us on how to assemble this, unless there is a rule that specifically makes this illegal (which I was unable to find), as far as I am concerned it should be legal.

[Al Skierkiewicz]

Brian,
I agree that the instructions from Rockwell say it can be cut. But the normal use of this system is inside an enclosure where there will be no contact with other parts, electrical and mechanical. Our use has not been fully considered for insulating the cut ends and I am hoping that the GDC addresses this in the future.

[BrianBSL]

Originally Posted by Al Skierkiewicz

Brian,
I agree that the instructions from Rockwell say it can be cut. But the normal use of this system is inside an enclosure where there will be no contact with other parts, electrical and mechanical. Our use has not been fully considered for insulating the cut ends and I am hoping that the GDC addresses this in the future.

The instructions don't seem to be generic, however, as the drawing has FIRST in the part number, and the written instructions specifically reference that drawing.

[Al Skierkiewicz]

Note that the drawing and instruction sheet in your link all have "Rockwell" on them. I believe that the drawing was made for FIRST but that the instruction sheet is the one provided to installers by Rockwell.

[seanl]

are the ground wires from the speed controllers that go to the 4 cims required to be connected to the block. currently i have them connected through the breakers.

[Al Skierkiewicz]

Originally Posted by seanl

are the ground wires from the speed controllers that go to the 4 cims required to be connected to the block. currently i have them connected through the breakers.

Yes, that is the recommended method. See the latest revision of the electrical drawing and the Tips & Guidelines. It also minimizes the voltage losses to the RC due to the high currents of the motors passing through the smaller fuse panel. I know this is hard to visualize but the current provided to a motor (speed controller power in) and the current returning from the motor is the same. Since a Chalupa motor stalls at a over 100 amps, that current is flowing through both the red and black wire. For every foot of #10 (black or red)that equates to a 0.1 volt drop.

[seanl]

i know that it is what is recommeded but would we pass inspection if its connected through the breaker.

[Al Skierkiewicz]

Sean,
I would say that this is a question for the Q&A to be sure. However, in my opinion, I would say no, under this part of the robot rules...
<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.
Sorry.