Go to Post Celebrate your failures as well as your successes. - Taylor [more]
Home
Go Back   Chief Delphi > Technical > Electrical
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 20-11-2013, 18:12
tessa.krause tessa.krause is offline
Registered User
AKA: Tessa
FRC #4627 (Iron Manning)
Team Role: Electrical
 
Join Date: Nov 2013
Rookie Year: 2012
Location: Calgary
Posts: 1
tessa.krause is an unknown quantity at this point
Two Power Distribution boards?

This year my team is looking at using a lot more motor controllers so we are considering using two power distribution boards. I'm not sure if this is legal and if it is, how I would do it. Thanks for any input!
  #2   Spotlight this post!  
Unread 20-11-2013, 18:41
cgmv123's Avatar
cgmv123 cgmv123 is offline
FRC RI/FLL Field Manager
AKA: Max Vrany
FRC #1306 (BadgerBOTS)
Team Role: College Student
 
Join Date: Jan 2011
Rookie Year: 2011
Location: Madison, WI
Posts: 2,089
cgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond repute
Re: Two Power Distribution boards?

Obligatory disclaimer that last year's rules are not this year's.
__________________
BadgerBOTS Robotics|@team1306|Facebook: BadgerBOTS
2016 FIRST Championship Tesla Division | 2016 Wisconsin Regional Engineering Inspiration Award

2015 FIRST Championship Carson Division | 2015 Wisconsin Regional Chairman's Award

2013 FIRST Championship Curie Division | 2013 Wisconsin Regional Chairman's Award

2012 FIRST Championship Archimedes Division | 2012 Wisconsin Regional Engineering Inspiration Award, Woodie Flowers Finalist Award (Lead Mentor Ben Senson)

  #3   Spotlight this post!  
Unread 20-11-2013, 18:48
aryker's Avatar
aryker aryker is offline
Registered User
FRC #0868 (TechHOUNDS)
Team Role: Mentor
 
Join Date: Jan 2013
Rookie Year: 2008
Location: United States
Posts: 80
aryker will become famous soon enougharyker will become famous soon enough
Re: Two Power Distribution boards?

How many motors are you planning to use, and which kinds? Usually the manual has a maximum number of allowed motors of each type. For example, last year, teams could use a maximum of 6 CIM motors.
  #4   Spotlight this post!  
Unread 20-11-2013, 19:10
EricH's Avatar
EricH EricH is online now
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 19,824
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Two Power Distribution boards?

With the disclaimer above firmly attached, I point you to the 2013 rule R38, emphasize the wording "the Power Distribution (PD) Board" (which, I might add, is repeated in multiple locations later in that section of the robot manual), and as a former inspector remind you that the rule says that you gotta match the figure in that rule--in short, sorry, only one PDB is allowed.

I then go to R47 to remind you that only one motor controller or relay circuit is allowed per breaker, in case you were thinking of running 2 controllers from one output.

In short... not legal. Maybe you should look into pneumatics or servos; those are less limited in number, and have more flexibility to add a control area--but they also have limitations like limited power or limited positioning.
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk

  #5   Spotlight this post!  
Unread 20-11-2013, 19:20
BBray_T1296's Avatar
BBray_T1296 BBray_T1296 is offline
I am Dave! Yognaut
AKA: Brian Bray
FRC #1296 (Full Metal Jackets)
Team Role: Mentor
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Rockwall, TX
Posts: 947
BBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond reputeBBray_T1296 has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by tessa.krause View Post
This year my team is looking at using a lot more motor controllers so we are considering using two power distribution boards.
If you are using so many motors you need a second distribution board, chances are you likely will be operating awfully close to the 120Amps it takes to snap the Main Breaker (if not above 120A!).

I cannot find a specific rule disallowing the use of a second PDB, but I have never seen it before. In 2012 we had 15* motors each on their own Victor/Spike/Jag. We were cutting it close on slots, but we still had 2-3 left at the end. We never had a current problem, but I would bet we were running above 100A at times.

My $0.02: If your robot takes that many motors, your robot probably needs to be redesigned. 15* motors was a bad idea, because of complexity and the shear weight of the things. Our robot this year had a total of just 5 motors. 4 were in the drive-train.



*Plus 1 Vex motor, but it only needs the power given off by the Sidecar via PWM.
__________________
If molecular reactions are deterministic, are all universes identical?

RIP David Shafer: you will be missed


  #6   Spotlight this post!  
Unread 20-11-2013, 19:25
FrankJ's Avatar
FrankJ FrankJ is offline
Robot Mentor
FRC #2974 (WALT)
Team Role: Mentor
 
Join Date: Feb 2011
Rookie Year: 2009
Location: Marietta GA
Posts: 1,946
FrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond repute
Re: Two Power Distribution boards?

I would expect it would be ruled as illegal. But that is just an opinion. That aside, two lugs on the studs of the PD board would be OK if there is enough clearance to the body. Otherwise splice the wires before PD board. I probably would use the same compression lugs, bolt them together & tape them.
  #7   Spotlight this post!  
Unread 20-11-2013, 20:44
yash101 yash101 is offline
Curiosity | I have too much of it!
AKA: null
no team
 
Join Date: Oct 2012
Rookie Year: 2012
Location: devnull
Posts: 1,191
yash101 is an unknown quantity at this point
Re: Two Power Distribution boards?

You'd probably shoot through the battery, drawing that much power on your robot. I doubt that everything will run at the same time!
  #8   Spotlight this post!  
Unread 20-11-2013, 20:45
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,599
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by FrankJ View Post
That aside, two lugs on the studs of the PD board would be OK if there is enough clearance to the body. Otherwise splice the wires before PD board. I probably would use the same compression lugs, bolt them together & tape them.
R39 makes that illegal.
  #9   Spotlight this post!  
Unread 20-11-2013, 21:04
Jim Wilks Jim Wilks is offline
Electrical Engineer
AKA: Jim Wilks
FRC #1360 (Orbit Robotics)
Team Role: Mentor
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Oakville, ON
Posts: 1,186
Jim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond reputeJim Wilks has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by tessa.krause View Post
This year my team is looking at using a lot more motor controllers so we are considering using two power distribution boards. I'm not sure if this is legal and if it is, how I would do it. Thanks for any input!
The new PDB for 2015 is being tested by a few teams. I has less "slots" on the PDB than the current one. Time to start thinking about less, not more PDB outputs.
__________________
Jim

  #10   Spotlight this post!  
Unread 20-11-2013, 22:03
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,599
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by Jim Wilks View Post
The new PDB for 2015 is being tested by a few teams. I has less "slots" on the PDB than the current one. Time to start thinking about less, not more PDB outputs.
The 2015 control system also uses up less slots then the current system.
  #11   Spotlight this post!  
Unread 20-11-2013, 22:43
yash101 yash101 is offline
Curiosity | I have too much of it!
AKA: null
no team
 
Join Date: Oct 2012
Rookie Year: 2012
Location: devnull
Posts: 1,191
yash101 is an unknown quantity at this point
Talking Re: Two Power Distribution boards?

If this isn't a competition robot (Which I doubt it wouldn't be), just jam multiple wires in the same slots . You are probably not going to be using every motor at the same time, are you?

Just make sure you do it right. The "Cheap n Dirty" way of doing things is why many battery explosions and fires happen!
  #12   Spotlight this post!  
Unread 20-11-2013, 22:47
MichaelBick MichaelBick is offline
Registered User
FRC #1836 (MilkenKnights)
Team Role: Alumni
 
Join Date: Oct 2011
Rookie Year: 2010
Location: Los Angeles
Posts: 734
MichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant futureMichaelBick has a brilliant future
Re: Two Power Distribution boards?

Quote:
Originally Posted by yash101 View Post
If this isn't a competition robot (Which I doubt it wouldn't be), just jam multiple wires in the same slots
That makes them a lot more likely to trip the 40/30/20A breakers
__________________
Team 1836 - The Milken Knights
2013 LA Regional Champions with 1717 and 973
2012 LA Regional Finalists with 294 and 973
To follow Team 1836 on Facebook, go to http://www.facebook.com/MilkenKnights
To go to our website, go to http://milkenknights.com/index.html
  #13   Spotlight this post!  
Unread 20-11-2013, 22:52
yash101 yash101 is offline
Curiosity | I have too much of it!
AKA: null
no team
 
Join Date: Oct 2012
Rookie Year: 2012
Location: devnull
Posts: 1,191
yash101 is an unknown quantity at this point
Talking Re: Two Power Distribution boards?

Yes. I agree. That is why you group the motors that you know will rarely work together. Blooper: However, when doing this, a fire extinguisher is recommended because a wire can slip and short out!
  #14   Spotlight this post!  
Unread 21-11-2013, 08:45
Jon Stratis's Avatar
Jon Stratis Jon Stratis is offline
Mentor, LRI, MN RPC
FRC #2177 (The Robettes)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Minnesota
Posts: 3,835
Jon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by tessa.krause View Post
This year my team is looking at using a lot more motor controllers so we are considering using two power distribution boards. I'm not sure if this is legal and if it is, how I would do it. Thanks for any input!
You've heard from others that using two would be illegal, given last year's rules. Since the rules quoted above haven't really changed much over the past few years, you can probably assume they won't change much this year, either.

However, your post brings up another concept... The game hasn't been released yet, the season hasn't started. How do you know how many motor controllers you'll need?
__________________
2007 - Present: Mentor, 2177 The Robettes
LRI: North Star 2012-2016; Lake Superior 2013-2014; MN State Tournament 2013-2014, 2016; Galileo 2016; Iowa 2017
2015: North Star Regional Volunteer of the Year
2016: Lake Superior WFFA
  #15   Spotlight this post!  
Unread 21-11-2013, 09:24
FrankJ's Avatar
FrankJ FrankJ is offline
Robot Mentor
FRC #2974 (WALT)
Team Role: Mentor
 
Join Date: Feb 2011
Rookie Year: 2009
Location: Marietta GA
Posts: 1,946
FrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond repute
Re: Two Power Distribution boards?

Quote:
Originally Posted by Joe Ross View Post
R39 makes that illegal.
Given the fragile nature of the M6 studs, I probably would not put more than one lug on them anyway. But. R39 refers to circuits that should be downstream PD board. To fully follow R39, the 2nd PD board would have to get its power from the first PD board which would limit the available power to the 2nd board to 40 amps. (Max breaker size). Of course then you run foul of R47 which limits loads through one breaker of the first PD board.

I think of the more of a thought exercise than reality since more than one PD legal is probably not legal to begin with.
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 19:25.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi