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-   -   [B]Minibot[/B] (http://www.chiefdelphi.com/forums/showthread.php?t=89585)

Brandon Holley 21-01-2011 12:15

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by pfreivald (Post 1004677)
Buy lots, and keep them handy!

Very good advice, I highly recommend everyone follows it.

-Brando

Mr. B 21-01-2011 12:38

Re: [B]Minibot[/B]
 
What do you think is causing the fuses to blow?

Jon Stratis 21-01-2011 12:55

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by Mr. B (Post 1005011)
What do you think is causing the fuses to blow?

Simple answer? You're pulling too much current through them!

The problem with fuses like this is that it doesn't take much to blow them. Stall your motors, and they'll blow pretty quickly. There's a similar fuse in each Spike, and those can be blown just from the startup current from the KoP compressor! Because of this, a few years ago FIRST started allowing teams to replace those with the 20A snap action breakers from the power distribution board (Although since we aren't doing pneumatics, I haven't read that section of the manual and can't say for certain it's allowed this year as well). It would be pretty nice if FIRST allowed a similar modification to this component, although I have to stress - unless allowed through a team update or a Q&A, your stuck using the fuses.

Jared Russell 21-01-2011 14:52

Re: [B]Minibot[/B]
 
The mounting clamps for the Tetrix motors were the cause of nearly all of our blown fuses thus far - the motors will rotate in their housings over time, which has caused gears on the output shaft to mesh too tightly, stalling the motors.

Just one thing to keep an eye on.

konk25 21-01-2011 18:37

Re: [B]Minibot[/B]
 
Thank you everybody,
I was looking at the list of what we can use on the minibot, and I found out that we can use aluminium sheets.

So are we allowed to make stuff out out aluminium sheets?

Thank you :)

klmx30302 21-01-2011 18:40

Re: [B]Minibot[/B]
 
Our team thinks the cause is not starting the motors before the minibot is on the poll. we think that the startup load is increased and the fuse blows, we were going to test this tonight but we have no school so no meeting.

Polaris395 21-01-2011 18:49

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by konk25 (Post 1005253)
Thank you everybody,
I was looking at the list of what we can use on the minibot, and I found out that we can use aluminium sheets.

So are we allowed to make stuff out out aluminium sheets?

Thank you :)

Based on the validity of the first statement: Yes, you may.

Bill_B 21-01-2011 18:54

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by Jared341 (Post 1005087)
The mounting clamps for the Tetrix motors were the cause of nearly all of our blown fuses thus far - the motors will rotate in their housings over time, which has caused gears on the output shaft to mesh too tightly, stalling the motors.

Just one thing to keep an eye on.

Are you clamping the motor or the gearbox? The supplied clamp fits best over the gearbox which is slightly larger diameter. If you are clamping the motor casing, I wouldn't predict a good outcome to that situation.

Fuses can be blown by stalling the motor, causing over-current. Also easy to blow fuses if you are using alligator clip connections to the motor supply tabs. Solder some heavy gauge stranded wire in two different lengths to those tabs and shrink some insulation over them. Then make your motor connections to those wires at the offset other ends. This will reduce the number of accidental shorts and save you a bunch of fuses.

boomergeek 21-01-2011 19:22

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by Bill_B (Post 1005267)
Are you clamping the motor or the gearbox? The supplied clamp fits best over the gearbox which is slightly larger diameter. If you are clamping the motor casing, I wouldn't predict a good outcome to that situation.

Fuses can be blown by stalling the motor, causing over-current. Also easy to blow fuses if you are using alligator clip connections to the motor supply tabs. Solder some heavy gauge stranded wire in two different lengths to those tabs and shrink some insulation over them. Then make your motor connections to those wires at the offset other ends. This will reduce the number of accidental shorts and save you a bunch of fuses.

I did not see solder on the allowed list of parts for the minibot. (Nor did I see simple electicial connectors that are equivalent but not exactly TETRIX parts).
Cannibalizing solder off hundreds of TETRIX pieces would probably be deemed legal based on the current rules.;)

Was anyone seen a GDC ruling on solder on the minibot?

Al Skierkiewicz 22-01-2011 08:23

Re: [B]Minibot[/B]
 
The minibot rules change the robot rules for specific minibot items. Solder is allowed on the main robot and since it is not excluded in the minibot rules is allowed.

Mr_D_Mentor 27-01-2011 21:56

Re: [B]Minibot[/B]
 
This is good news. Since we already soldered wires to the motor, I was starting to think we would have to remove all the solder, which would be very difficult.

JB987 27-01-2011 22:47

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by Bill_B (Post 1005267)
Are you clamping the motor or the gearbox? The supplied clamp fits best over the gearbox which is slightly larger diameter. If you are clamping the motor casing, I wouldn't predict a good outcome to that situation.

Fuses can be blown by stalling the motor, causing over-current. Also easy to blow fuses if you are using alligator clip connections to the motor supply tabs. Solder some heavy gauge stranded wire in two different lengths to those tabs and shrink some insulation over them. Then make your motor connections to those wires at the offset other ends. This will reduce the number of accidental shorts and save you a bunch of fuses.

You can over tighten the clamp on the gearbox housing also...trust me, my new FTC team found that out the hard way.::ouch::

davidfv 27-01-2011 23:11

Re: [B]Minibot[/B]
 
Quote:

Originally Posted by DonRotolo (Post 1004630)
As in life, the more restrictive the rules, the more creative the 'best' solution will be. Even though the minibot cannot exceed a 1 foot cubical box, teams should be thinking outside that box :D

OR INSIDE THE BOX.


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