There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Hi!

I'm in charge of the electrical wiring for my team and I burst down crying in frustration today. We had finished mounting our kicking mechanism and the robot was basically done, we were just gonna practice driving. I turn on the robot and one of our Victor 888's just sparks really loud! I'm really frustrated and panicking right now! What could it be? Could it be that we connected the fans to the V+ V- part of the Victor so it could get it's power from there? How do you guys wire your fans/Victors?? PLEASE HELP!!! TODAY IS BAG AND TAG!!!!

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

could be metal debris in the controller. A fan properly connected should not cause issues on the V+/- side. The mounting hole is close to the terminals and could cause issues if the screw head is too big. Make sure the terminals are free from debris.

Sounds like you might have debris on the terminals if the victor is still working.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Thanks! I will check up on that first thing!

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Metal chips entering Victor result from not so careful drilling & filing i.e. lack of prior adequate protective covering over electronics+motors to catch metal flakes (usually aluminium) as the typical culprit leading to sparks, smoke & destruction from highly conductive metal slivers which easily enter under the fan ....into the big unprotected air hole in Victors... over & cooling the H-bridge FETs (high current electronic switches) Fan helps to maintain lowest temp = lowest possible "ON" resistance from positive temp coefficient of FET (=loss = heat via P=I^2R watts when FET turns ON)

A second cause of failure albeit less frequent is "high voltage spike punch through" source to drain =high current path of the Victors FETs shorts +12v to ground withing thes 9 parrallel devices, resulting in sparks, smoke and sometimes fire depending on how fast the circuit breaker trips.

Such high voltage spikes are unavoidable in PWM switchers, as physics demands when energy is stored in an inductor via magnetic field (motor armature) then abruptly removed, the voltage increases as the field cuts quickly the through multiple windings, Voltage approaches infinity!!

V=L/time short transition time in PWM result in very high voltage spikes

(or until something breaks down like the enamel insulation on magnet wire)

so the design must consider this and protect the FETs

.. occassionally built-in protections fail and sparks fly.

It is amazing it doesnt happen more frequently.. but it does happen! in this case it is not your fault nor one you have control.

Merely replace the Victor... and assure NO metal filings enter in the future (instruct team to cover all electronics prior to filing drilling and be careful removal of cover not let any fdebris fall into electrical areas. (also the vents holes of motors are vulnerable to such contamination shorts)

Good Luck this year...

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

you should post a picture of your all your electronics with a focus on the damage you see.

If there was a spark or popping in your Victor 888 you should disconnect from your electronics board and not use it again. inspect it for burn marks and a burnt electronics smell.

Like others have mentioned, if its your first time working with FRC electronics you should know that shavings of any conductive material like aluminum and steel WILL destroy your electronics once powered causing unexpected but disastrous results. if one victor has failed you MUST check all of your equipment as it likely been exposed to other metal shavings..

Use a compressor or a compressed air can to clean off all your electronics internally and begin forming a plan to purchase new speed controllers.

Even if today is bag and tag day you can form a plan to replace these components ASAP and use the withholding allowance to not pack your electronics board with the rest of your robot. this will allow you time to focus on recovering from your dilemma before your first regional.

ALSO: if u need a replacement today.. find the nearest teams around you and see if they would lend/sell you their Victors or Jaguars or Talons today!

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Has it done this on more than one occasion? Have you double checked the polarity of the wiring from the Power Distribution Board and the Victor? An experienced mentor on our team killed a Talon earlier this year because he accidentally wired it up backward. Simple mistakes happen - always look for them.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

It sounds like metal shavings have found their way under the fan and you have experienced your first, "oops I should have covered that with something" moment of the season.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Also, don't panic. Even if you cannot get everything working today, you will not be the only team bagging a non-functional robot.

When you arrive at your first event, have a plan for what you need to do; if you run into trouble, ask another team for help. It's always frustrating to see things go up in smoke, but it happens to everyone, just stay calm, fix what you can and make plans for what you haven't fixed at bag time.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Chi,
Don't let the end of build get to you. Your robot doesn't have to be working when it goes in the bag. We will help you get functional at your event. You will have plenty of help. Is Midwest your first and only event? I will be there and we will get you working. If you suspect it might be a defective Victor, take it off your robot and you can send it to IFI for a check and possible repair or you can order a spare. Don't worry, the best part of your season is yet to come.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Thank you for your words of encouragement! It means a lot to us!
-CHIHOPEROBOTICS

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Are we not allowed to come in and work on it for a certain time before the competition begins?

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Could they still work? We turned on the robot today and they were working just fine, the lights were blinking normally and it was as if nothing had happened.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

We're using 10 gauge wire to connect our motor controllers to our power distribution board, is that good? And could we use the motor controllers again? We turned it on today and it was as if nothing had ever happened. They were blinking normally and everything.

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Once your robot is in the bag, you can't interact with it (other than moving the whole bag around, say to the car for travel to the event) until you open the bag at your next event.

You might have seen that you can, but you aren't in an area where that applies (MI is the closest area like that to you).

Re: There was an explosion!!! (URGENT! TODAY IS BAG AND TAG!)
 

Yes, that is good.

If everything works...then everything is working. Normally one does not "repair" something that is working. Right?