Re: blog; Motor Controller Options for 2015
 

Removing the screws on most motor controllers creates debris within the motor controller as a consequence (i.e. it doesn't have to fall in, it is already there). If I recall correctly, both Jaguar and Victor (at least 884) use captive screw terminals. When the screws are removed, little bits of the removed screw are left behind. This was a bigger problem for Jaguar due to the lack of conformal coating (before VEX manufacture).

Re: blog; Motor Controller Options for 2015
 

I wonder if FRC would consider brushless motors & controllers in the future. Since the popularity of quadcopters exploded, there are tons of cheap options available

Re: blog; Motor Controller Options for 2015
 

If they run into a problem and these end up not being legal, I foresee a motor controller shortage next year. I'm glad we have about 20 talons, which should be enough for next year.

Also, not sure how I feel about the pigtails. Especially since they are only #12 gauge. I would have preferred to see #10 gauge, or a version with screw terminals for the teams that want to use them.

Re: blog; Motor Controller Options for 2015
 

The screw terminals would have dictated a larger packaging.

We were planning on leaving anderson pigtails on each end of EVERY speed controller going forward on 973, glad they made that decision for us essentially.

It's different, but I don't see it being a problem. If we had pigtails for 10+ years then switched to screw terminals people would be bothered in the other direction.

Re: blog; Motor Controller Options for 2015
 

I wouldn't be too worried. CIM motors come with even smaller #14 gauge wires, and teams have been fine with this. If you're very concerned with performance, you can trim the pigtails very short, and you'll end up with a very small voltage drop.

Re: blog; Motor Controller Options for 2015
 

We used andersons on the robot this year and were very happy with them. This change will be a good fit with our current wiring practice. Now the whole robot frame becomes the heat sink.

Re: blog; Motor Controller Options for 2015
 

It's a cool thought, but the contact resistance probably still ensures that natural convection dominates.

Re: blog; Motor Controller Options for 2015
 

I realize these things probably aren't supposed to be grounded to their frame, but in the event that they are, I personally would still screw them through a non-conductive piece of material like corrugated plastic or lexan.

Re: blog; Motor Controller Options for 2015
 

The documents linked state that they are electrically isolated.

Re: blog; Motor Controller Options for 2015
 

I'm fine with the removal of the screw terminals. Andersons end up on our motor ends anyway and for a lot of our speed controllers we'll probably go directly in to the PD panel with the leads for power.

I'm more worried about the PWM cables being attached. We've had far more PWM wires go bad over the years than 12AWG wire. It's going to be a little more annoying to troubleshoot since you can't just swap the PWM wires around at the speed controller. However I am glad that they all come with wires and I would hope they are nice high quality cable and connectors.

Overall these seem like huge improvements over where we were in the past. These will be much easier to mount in hidden places since you don't really need to access them and it will be easier to mount spares on the robot in case a speed controller drops out. 610 has done this in the past but since these take even less room and it's hard to change wires with them, I think more teams wills start following that practice.

Re: blog; Motor Controller Options for 2015
 

Fair enough.
Though I would still prefer using corrugated plastic. Not only because it is light, but you can punch mounting holes in it by simply shoving a screwdriver through it. To each his/her own of course.

Re: blog; Motor Controller Options for 2015
 

VersaFrame holes can easily be used to mount these. Holes are already drilled.

Re: blog; Motor Controller Options for 2015
 

My only question is what is the pinout for feedback pins on the SRX?

I only counted 10 pins on the feedback connector, but the Jag has 12 ( 5 - encoder, 3 Analog Input, 2x2 Limit Switches). I am sure a few pins are doubled up but I wonder which ones?

Re: blog; Motor Controller Options for 2015
 

You bring up a really good point about the PWM cables. It's surprising easy to damage one. We had a few issues with some PWM cables this year that took out one of our drivetrain motors. We had enough time to swap the cable during our 4 back to back matches, but if we had to take the controller out, it would have been much harder.

That said, our PWM cables were likely very low quality because after the incident, I was able to cause another PWM cable on our test board to fail by just bending it back a forth a few times.

Re: blog; Motor Controller Options for 2015
 

Great points Allen! Was thinking the same thing.