Go to Post Woody, If there is any chance your reading this ... you've changed my life. - Gope [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

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #346   Spotlight this post!  
Unread 28-01-2012, 19:55
EricVanWyk EricVanWyk is offline
Registered User
no team
 
Join Date: Jan 2007
Rookie Year: 2000
Location: Boston
Posts: 1,597
EricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond repute
Send a message via AIM to EricVanWyk
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by Al Skierkiewicz View Post
To what are you referring to as UVLO?
Under Voltage Lock Out. This is the generic term for a processor or device shutting itself down when it doesn't have sufficient voltage to guarantee correct behavior.
  #347   Spotlight this post!  
Unread 28-01-2012, 20:56
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1996
Location: Wheeling, IL
Posts: 10,792
Al Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond reputeAl Skierkiewicz has a reputation beyond repute
Re: Banebots RS-775 Case Short

Eric,
The PD is very well designed and works very well. Without any valid data I cannot tell you which trips first since the effect is the same, that is Crio reboot. With the relatively low impedance of the motor wiring back to the PD compared to the higher impedance of the Crio power wiring, it would appear that the majority of the fault current would flow back through the motor wirin when we first observed this fault, we were prototyping with a small motor that we had removed from a battery operated vacuum. The motor case was intentionally wired to one of the wires. I don't think the motor drew more that 10 amps.
__________________
Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
________________________
Storming the Tower since 1996.
  #348   Spotlight this post!  
Unread 30-01-2012, 09:20
camtunkpa camtunkpa is offline
it's like shooting fish in a barrel
AKA: Cliff Mock
FRC #0222 (Tigertrons)
Team Role: Engineer
 
Join Date: Oct 2002
Rookie Year: 1997
Location: Tunkhannock, PA
Posts: 580
camtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond reputecamtunkpa has a reputation beyond repute
Re: Banebots RS-775 Case Short

An update from 222. Our shooter using 2 775s has been working flawlessly. We have been periodically checking the 775s to make sure they check out ok. We've put about 60-70 shots through it between last week and this weekend. So far so good.
__________________
"Engineering is making the impossible happen"
"We are here to create, not merely survive" - unknown fortune cookie
"If you don't push the envelope you're just spinning your wheels"
  #349   Spotlight this post!  
Unread 30-01-2012, 09:22
Andrew Lawrence
 
Posts: n/a
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by camtunkpa View Post
An update from 222. Our shooter using 2 775s has been working flawlessly. We have been periodically checking the 775s to make sure they check out ok. We've put about 60-70 shots through it between last week and this weekend. So far so good.
Same here! 256 has had no problems with our 775's.
  #350   Spotlight this post!  
Unread 30-01-2012, 16:43
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: Banebots RS-775 Case Short

On a more positive note, I received 6 RS-775-18's today from Banebots. All test out fine!
  #351   Spotlight this post!  
Unread 30-01-2012, 18:36
Aren Siekmeier's Avatar
Aren Siekmeier Aren Siekmeier is offline
on walkabout
FRC #2175 (The Fighting Calculators)
Team Role: Mentor
 
Join Date: Apr 2008
Rookie Year: 2008
Location: 대한민국
Posts: 735
Aren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond repute
Re: Banebots RS-775 Case Short

2175 has had 775s chugging through some shooter tests that we "borrowed" from last year's robot, and they've had no problems so far. Haven't done any case short tests since we first got them last year. However, because there are so many other motors available, we're going with 550s on the competition shooter just to avoid the headache other teams have experienced, and keep the 775s around for other testing. The 550s are just 20W less powerful than the 775s, and we think we can get by.
  #352   Spotlight this post!  
Unread 30-01-2012, 19:02
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,094
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by compwiztobe View Post
The 550s are just 20W less powerful than the 775s, and we think we can get by.
Although I doubt you'll be running them at max power for any length of time (at least I hope not), let's do some numbers anyway just for grins:

at max power of 251 watts, the 550-12 generates 267 watts of waste heat.

at the same power output of 251 watts, the 775-18 generates only 141 watts of waste heat.

the mass of the 550-12 is 218 grams. the mass of the 775-18 is 337 grams.

the ratio of waste heat to mass is therefore

550-12: 267/218 = 1.22

775-18: 141/337 = 0.42



Last edited by Ether : 30-01-2012 at 19:09. Reason: typo
  #353   Spotlight this post!  
Unread 30-01-2012, 21:55
Aren Siekmeier's Avatar
Aren Siekmeier Aren Siekmeier is offline
on walkabout
FRC #2175 (The Fighting Calculators)
Team Role: Mentor
 
Join Date: Apr 2008
Rookie Year: 2008
Location: 대한민국
Posts: 735
Aren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond reputeAren Siekmeier has a reputation beyond repute
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by Ether View Post
Although I doubt you'll be running them at max power for any length of time (at least I hope not), let's do some numbers anyway just for grins:

at max power of 251 watts, the 550-12 generates 267 watts of waste heat.

at the same power output of 251 watts, the 775-18 generates only 141 watts of waste heat.

the mass of the 550-12 is 218 grams. the mass of the 775-18 is 337 grams.

the ratio of waste heat to mass is therefore

550-12: 267/218 = 1.22

775-18: 141/337 = 0.42


Yep, these are going somewhere where they're seeing mostly intermittent duty (not at max power when free wheeling, probably powering shooter down when collecting balls), so we aren't concerned about the heat. But it's interesting to see that comparison.
  #354   Spotlight this post!  
Unread 07-02-2012, 19:50
jason701802's Avatar
jason701802 jason701802 is offline
Registered User
FRC #0753 (The High Desert Droids)
Team Role: College Student
 
Join Date: Jan 2007
Rookie Year: 2002
Location: Oregon/Univ. of Southern Calif.
Posts: 234
jason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant futurejason701802 has a brilliant future
Re: Banebots RS-775 Case Short

Has anyone received any 775s recently who can comment on the condition in which the motors arrived?
__________________
Jason
  #355   Spotlight this post!  
Unread 08-02-2012, 05:26
mehrkam's Avatar
mehrkam mehrkam is offline
Paul Mehrkam
FRC #0836 (Robobees 836)
Team Role: Mentor
 
Join Date: Oct 2010
Rookie Year: 2007
Location: Leonardtown, MD
Posts: 17
mehrkam is on a distinguished road
Re: Banebots RS-775 Case Short

We received 12 RS-775-V18 motors.

Test ran unloaded for 20 min
Checked for Case Short - none

Then we started using one on the shooter.. After some testing, case shorting was detected. That motor is begining to degrade and run at a higher temperature. We plan to use it till it drops. We want to develop a replacement and reliability plan for the motors in this application.

We implemented modifcations to improve cooling of the motor based on of the other threads. These included a spacer between motor and the CIMulator to permit air flow into the motor and cooling fins on the motor case.
  #356   Spotlight this post!  
Unread 08-02-2012, 19:54
SoloRacr SoloRacr is offline
Registered User
FRC #0907
 
Join Date: Jan 2012
Location: Canada
Posts: 4
SoloRacr is an unknown quantity at this point
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by jason701802 View Post
Has anyone received any 775s recently who can comment on the condition in which the motors arrived?
Team 907 has just received two RS-775-18's
One has a case short.

so, 50% failure rate


Andrew Paul
907 Mentor
EYCI
  #357   Spotlight this post!  
Unread 09-02-2012, 13:20
de_ de_ is offline
Registered User
AKA: Dave Edwards
FRC #1310 (Runnymede Robotics)
Team Role: Mentor
 
Join Date: Apr 2005
Rookie Year: 2005
Location: Toronto, Ontario
Posts: 256
de_ is a jewel in the roughde_ is a jewel in the roughde_ is a jewel in the roughde_ is a jewel in the rough
Re: Banebots RS-775 Case Short

re motors coming from factory shorted

Wow. Even after last years feedback, the manufacturer has still not solved the problem. Worst still they apparently are not even doing simple QA tests on them before shipping. We (or Banebots) need a new motor supplier. I have 6 of these on order and I can't see how I can risk using them.
  #358   Spotlight this post!  
Unread 09-02-2012, 14:01
slijin's Avatar
slijin slijin is offline
Pockets
AKA: Samuel Lijin
FRC #0694 (StuyPulse)
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2010
Location: New York City
Posts: 537
slijin is a splendid one to beholdslijin is a splendid one to beholdslijin is a splendid one to beholdslijin is a splendid one to beholdslijin is a splendid one to beholdslijin is a splendid one to beholdslijin is a splendid one to behold
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by de_ View Post
re motors coming from factory shorted

Wow. Even after last years feedback, the manufacturer has still not solved the problem. Worst still they apparently are not even doing simple QA tests on them before shipping. We (or Banebots) need a new motor supplier. I have 6 of these on order and I can't see how I can risk using them.
As Banebots has pointed out, they do run tests on their motors before shipping them out and advise any teams who receive bad motors to contact them asap. It's my opinion that motor defects upon receipt are the result of poor packaging (the shipment of 775s we received yesterday had pieces of broken Styrofoam, which I assume was there hold the 775s stable during transit).

We received a shipment of 4 775s yesterday, none of which had case shorts and were fully functional.
__________________

2010-12 CT Chairman's
2011 Galileo 5th seed
2010 NY Regional Winners
  #359   Spotlight this post!  
Unread 09-02-2012, 14:31
EricVanWyk EricVanWyk is offline
Registered User
no team
 
Join Date: Jan 2007
Rookie Year: 2000
Location: Boston
Posts: 1,597
EricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond repute
Send a message via AIM to EricVanWyk
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by de_ View Post
re motors coming from factory shorted

Wow. Even after last years feedback, the manufacturer has still not solved the problem. Worst still they apparently are not even doing simple QA tests on them before shipping. We (or Banebots) need a new motor supplier. I have 6 of these on order and I can't see how I can risk using them.
This problem has been notoriously intermittent, and I don't know of a good way to know whether a particular motor doesn't have the issue. Detecting a case short is a certain way to know that there is a problem, but not detecting the short doesn't mean that there isn't a problem. Rotating or jostling the motor can hide or expose the defect.

I'm of the opinion that the "case-zap" method doesn't fix or clear anything, it just shakes things up hard enough to push the defect back into hiding for a bit. It can then pass bench testing until something else causes it to express again.

I'm willing to believe that Banebots is performing best faith QA, and that the defect is too finicky to be caught by their testing. My suggestion is to teams is to treat all of these motors as defective regardless of testing and isolate them appropriately or switch to a different motor.
  #360   Spotlight this post!  
Unread 15-02-2012, 02:21
RRLedford RRLedford is offline
FTC 3507 Robo Theosis -- FRC 3135
AKA: Dick Ledford
FRC #3135 (Robotic Colonels)
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2009
Location: Chicago, IL USA
Posts: 286
RRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond reputeRRLedford has a reputation beyond repute
Re: Banebots RS-775 Case Short

Quote:
Originally Posted by jason701802 View Post
Has anyone received any 775s recently who can comment on the condition in which the motors arrived?
Team 3135 placed initial order for a pair of CIM-U-lator=>775 gearboxes recently (on Feb 1st)), along with a total of four 775 motors. Because of the internal shorting problem, we wanted to have spares.
Expecting at worst maybe one in four to test bad, our order arrived today with THREE SHORTED MOTORS (zero ohms) out of four. We are bailing out on using the 775 motors for ANYTHING EVER AGAIN. I hope we can get a replacement pair of DUAL 550 CIM-U-lator gearboxes shipped ASAP. Banebots may be testing these 775 motors, but if so, USPS is killing them in transit. Packing was adequate but not very good considering the known issues. The motors should have been rolled up with multi layer bubble pack surrounding them, and they were not.

FOLLOW-UP - GOOD NEWS
Banebots agreed to send us by overnight ship two back plates that would let us convert the CIM-U-llator gearboxes over from RS775 to RS550 (single or dual). Right now it's only for lack of the big gears and output shafts that is slowing down CIM-U-lator deliveries, but the aluminum plates are in stock. So, this lets us use dual 550 motors instead of 775s.
So, they sold us the two back plates for the price of one complete CIM-U-lator, and 3 extra mounting kits were also included.
BTW, for those waiting for 550 CIM-U-lators to ship, they would not move us to the head of the queue to swap a single 550 CIM-ulator gearbox for our one unusable 775 gearbox simply because of the three shorted 775 motors, even though we offered to overnight return the one of the 775 CIM-U-lator to get a 550 replacement. They understood that we no longer trusted using 775 motors, even free replacements, so, instead they proposed getting us the 550 backplates .
With this compromise, we are happy and feel taken care of by Banbots.

-Dick Ledford

Last edited by RRLedford : 15-02-2012 at 14:01.
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 16:36.

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