OCCRA
Go to Post I remember as a kid thinking how high a team number like 834 was. - Dancin103 [more]
Home
Go Back   Chief Delphi > Technical > Motors
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #16   Spotlight this post!  
Unread 07-11-2018, 10:36 AM
BoilerMentor BoilerMentor is offline
Research Engineer, Medical
AKA: Charlie Baxter
FRC #1747 (Harrison Boiler Robotics)
Team Role: Mentor
 
Join Date: Jan 2011
Rookie Year: 2006
Location: West Lafayette, IN
Posts: 174
BoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond reputeBoilerMentor has a reputation beyond repute
Re: Fan for 775pros

Quote:
Originally Posted by Billfred View Post
I agree that active cooling is of limited utility during the match, though I would venture a fan setup for after the match is more valuable in bringing the motors down to ambient temperature.

I'll ask a couple about your particular setup: How did you implement your speed limits? Did you replace any motors during the season, either due to failures or as preventative maintenance?
Speed limits were imposed based on encoder feedback, no other programmatic protections were in place.

We didn't replace any motors through the course of the season on the practice or competition robot and haven't observed any degradation in robot performance to indicate that the system needs service.
__________________
2006-2008 FIRST Team 1741 Red Alert-Founding Student
2008-2011 FIRST Team 1747 Harrison Boiler Robotics-College Mentor
2012 FIRST Team 4272 Maverick Boiler Robotics-Founding College Mentor
2013-Present FIRST Team 1747 Harrison Boiler Robotics-Engineering Mentor
2015-2017 Ri3D Team Indiana - Mechanical and Fabrication
Reply With Quote
  #17   Spotlight this post!  
Unread 07-11-2018, 12:40 PM
philso philso is offline
Mentor
no team
 
Join Date: Jan 2011
Rookie Year: 2009
Location: Houston, Tx
Posts: 1,643
philso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond reputephilso has a reputation beyond repute
Re: Fan for 775pros

Quote:
Originally Posted by Billfred View Post
May, but testing has shown a fan blowing on the motor after hard running makes a meaningful impact. Maybe not enough to totally cool a CIM-based drivetrain between finals matches, but an 83% drop in cooling time for the air inside is significant in my book.

A 775-class drivetrain should be able to cool even faster, since it has less thermal mass, and I imagine big radiator fans cool a bit better than a 120mm KOP fan. (5402 used those in testing in 2017 mounted axially with respect to the CIMs, and they made a difference but didn't reach to the outside edges of the cans so there was definitely meat left on the bone.)

So I suppose the lesson is "let the fan run beyond the time the outer can is cooled to ambient", but how long is a matter for more instrumented testing (and then better data logging than Aren's post, though I appreciate him sharing what he has).

The testing described in the post linked does not show if the internal ambient air temperature rose again after the various forms of airflow were stopped. If the internal ambient temperature does not rise, the armature has truly been cooled. If the internal ambient does rise, the airflow has mainly flushed out the air that was heated.


I agree with Kevin's post, after the linked post, that the internal ambient temperature is not a good proxy for the armature temperature. From the many thermal tests I have had to do at several of my day jobs, I have found that a gap of 1-3 mm due to a thermocouple that detached from a heatsink will read between 5 and 20 degrees C lower than an adjacent one that is properly attached.
Reply With Quote
  #18   Spotlight this post!  
Unread 07-11-2018, 11:33 PM
N1ck N1ck is offline
Registered User
AKA: Nick
FRC #0323 (Lights Out)
Team Role: Mechanical
 
Join Date: Jan 2017
Rookie Year: 2013
Location: Mtn Home AR
Posts: 11
N1ck is a jewel in the roughN1ck is a jewel in the roughN1ck is a jewel in the rough
Re: Fan for 775pros

Another way to keep a 775 pro drive train alive is traction limiting. You give the motors all the power they want but limit how much of it can go to the ground. This year we ran a 8 motor 4 module parallel swerve. The only thing that kept the drive motors alive was limiting the wheel traction. (I am talking about 1 module) 2 775s drive 1 4x1in andymark performance wheel wrapped in wedge top tread. At full power it will break the wheel free and spin it back off and it regains traction. This gives max acceleration and keeps motors alive for. We ran 3 completions and a lot of practice on the same 8 motors. And before you go yelling how do you push its swerve that goes 18 ft/s it doesn't need to push. Ask anyone that watched 323s robot it is fast!

Nick
Reply With Quote
  #19   Spotlight this post!  
Unread 07-15-2018, 11:17 AM
Opher Shur Opher Shur is offline
Registered User
FRC #5951 (Makers Assemble)
Team Role: Electrical
 
Join Date: Mar 2018
Rookie Year: 2017
Location: Israel
Posts: 2
Opher Shur is an unknown quantity at this point
Re: Fan for 775pros

I know that team 1690 from Israel used a 775 chassis in 2018.

They didn't really find a way around stalling, they just cut the power once the motors were stalled. Though as earlier mentioned, you can set current limits in a way that lets your motors stall without risking an RS775, instead of shutting the power off all together.

Overall I know that 1690 were pretty satisfied from their chassis, though during the season they were very susceptible to defense.
Reply With Quote
  #20   Spotlight this post!  
Unread 07-17-2018, 09:25 PM
TA5R TA5R is offline
Registered User
AKA: Tarun A.
FRC #2367 (Lancer Robotics)
 
Join Date: Mar 2017
Rookie Year: 2016
Location: California
Posts: 2
TA5R is an unknown quantity at this point
Re: Fan for 775pros

Quote:
Originally Posted by N1ck View Post
At full power it will break the wheel free and spin it back off and it regains traction.
Could you please clarify how you did this?
Reply With Quote
  #21   Spotlight this post!  
Unread 07-17-2018, 09:39 PM
mman1506 mman1506 is offline
Reversible bumpers are my trigger
AKA: Marcus Quintilian
FRC #5406 (Celt-X)
Team Role: Mechanical
 
Join Date: Mar 2012
Rookie Year: 2012
Location: Toronto
Posts: 1,520
mman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond reputemman1506 has a reputation beyond repute
Re: Fan for 775pros

Quote:
Originally Posted by Billfred View Post
I agree that active cooling is of limited utility during the match, though I would venture a fan setup for after the match is more valuable in bringing the motors down to ambient temperature.

I'll ask a couple about your particular setup: How did you implement your speed limits? Did you replace any motors during the season, either due to failures or as preventative maintenance?
The thermal mass of a 775 pro isn't really high enough to take advantage of active cooling in between matches. Heat wasn't an issue at all for our 775 pro drive train this year. Our only 775 pro motor failures were due to the internal fan breaking off due to mechanical shock or debris.
__________________
2012-2015: 865 Warp7 Team Captain
2016/17: Free Agent Mentor
2018-present: 5406 Celt-X
Reply With Quote
  #22   Spotlight this post!  
Unread 07-18-2018, 04:28 PM
Cory Walters's Avatar
Cory Walters Cory Walters is offline
Registered User
FRC #2767
Team Role: Coach
 
Join Date: Jan 2014
Rookie Year: 2002
Location: michigan
Posts: 51
Cory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond repute
Re: Fan for 775pros

Here are some pictures of our cooling system we have on 2767s cart. 4 hoses, with 3d printed housings for the 775 pros. It's runs off a small shop vac.

https://drive.google.com/file/d/0B2f...w?usp=drivesdk

https://drive.google.com/file/d/0B2f...w?usp=drivesdk

https://drive.google.com/file/d/0B2f...w?usp=drivesdk

https://drive.google.com/file/d/0B2f...w?usp=drivesdk

https://drive.google.com/file/d/0B2f...w?usp=drivesdk
Reply With Quote
  #23   Spotlight this post!  
Unread 07-18-2018, 06:13 PM
Bluman56's Avatar
Bluman56 Bluman56 is offline
No more carpet ripping Robots
AKA: Nikita
FRC #2579 (LIC Robodogs)
Team Role: Mentor
 
Join Date: Jan 2015
Rookie Year: 2013
Location: Brooklyn, NYC
Posts: 300
Bluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant futureBluman56 has a brilliant future
Re: Fan for 775pros

Quote:
Originally Posted by Cory Walters View Post
Links don't work. Currently set as invite only.
Reply With Quote
  #24   Spotlight this post!  
Unread 07-18-2018, 06:22 PM
Cory Walters's Avatar
Cory Walters Cory Walters is offline
Registered User
FRC #2767
Team Role: Coach
 
Join Date: Jan 2014
Rookie Year: 2002
Location: michigan
Posts: 51
Cory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond reputeCory Walters has a reputation beyond repute
Re: Fan for 775pros

Quote:
Originally Posted by Bluman56 View Post
Links don't work. Currently set as invite only.
I believe I opened it up for viewing. Should be working now.
Reply With Quote
  #25   Spotlight this post!  
Unread 07-19-2018, 08:18 AM
Ryan Dognaux's Avatar
Ryan Dognaux Ryan Dognaux is offline
The Nature Bot - WOOOO!
FRC #1720 (PhyXTGears)
Team Role: Mentor
 
Join Date: Apr 2002
Rookie Year: 2001
Location: Muncie, IN
Posts: 2,909
Ryan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond reputeRyan Dognaux has a reputation beyond repute
Send a message via AIM to Ryan Dognaux
Re: Fan for 775pros

Quote:
Originally Posted by Cory Walters View Post
I believe I opened it up for viewing. Should be working now.
Thanks for sharing Cory. This is a fantastic idea even if you aren't running them in your drive train. Our 775s would get toasty in our elevator this year and having this would have been great, especially in districts with quick turnaround times.
__________________
Ryan Dognaux :: Last Name Pronounced 'Doane Yo'
Team 234 Alum: 2002 - 2005 :: Purdue FIRST Member: 2006 - 2009
Team 1646 Mentor: 2007 - 2009 :: Team 357 Mentor: 2009 - 2012
Team 4329 Mentor: 2013 - 2017 :: Team 1720 Mentor: Current
STL Off-Season Event: www.gatewayroboticschallenge.com
Reply With Quote
  #26   Spotlight this post!  
Unread 07-19-2018, 09:08 AM
Mark Wasserman's Avatar
Mark Wasserman Mark Wasserman is offline
Registered User
FRC #2767 (Stryke Force)
Team Role: Mentor
 
Join Date: May 2017
Rookie Year: 2010
Location: kalamazoo
Posts: 159
Mark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud ofMark Wasserman has much to be proud of
Re: Fan for 775pros

Quote:
Originally Posted by Ryan Dognaux View Post
Thanks for sharing Cory. This is a fantastic idea even if you aren't running them in your drive train. Our 775s would get toasty in our elevator this year and having this would have been great, especially in districts with quick turnaround times.
This is a good way to look at it.

This cooling system was originally designed around the 2017 robot to cool drive motors, which did full court sprints. It also cooled the shooter motor on the 2017 practice bot. In 2018 it was used primarily to cool azimuth motors on the practice bot.

Having just a single yellow adapter that can hook to a shop vac in your tool box would be quite handy and easy to make. About a minute to take a motor armature within 5 degrees ambient.
__________________
Not fast swerve, good swerve driven quickly.
Slow is Smooth, Smooth is Fast

Last edited by Mark Wasserman : 07-19-2018 at 09:37 AM. Reason: Flipped message order
Reply With Quote
  #27   Spotlight this post!  
Unread 07-20-2018, 01:50 AM
N1ck N1ck is offline
Registered User
AKA: Nick
FRC #0323 (Lights Out)
Team Role: Mechanical
 
Join Date: Jan 2017
Rookie Year: 2013
Location: Mtn Home AR
Posts: 11
N1ck is a jewel in the roughN1ck is a jewel in the roughN1ck is a jewel in the rough
Re: Fan for 775pros

Quote:
Originally Posted by TA5R View Post
Could you please clarify how you did this?
It was done by having just enough power to slip the wheels. think dragster. if the module is geared to have just enough power to slip the chosen wheel and traction surface. for us that is a 4x1 andymark performance wheel wrapped in wedgetop tread. there is no software limiting the motors they get what the battery will give them. If you need more info get in contact with John Novak or JT Novak i have explained it to the best of my ability.

Nick

Last edited by N1ck : 07-20-2018 at 01:56 AM.
Reply With Quote
Reply


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 01:06 PM.

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


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi