how much current does jag use

[imjessica]

we dont have 12 gauge wire so we are using 14 gauge/30 current amp breaker. is that enough current to be safe adn not have the circuit breaker going off over and over?

[1986titans]

If it recommends 12 gauge wire (and a quick check on AndyMark would indicate so), I wouldn't risk it.

[andreboos]

12 gauge wire is required for Jaguars (R44)

[RyanN]

Originally Posted by andreboos

12 gauge wire is required for Jaguars (R44)

I suggest you reread that rule.

[R44]

All active circuits shall be wired with appropriately sized wire:

Application
Minimum wire size
40A circuit: 12 AWG (2.052mm)
30A circuit: 14 AWG (1.628mm)

20A circuit: 18 AWG (1.024mm)
between the PD Board and the Analog and/or Solenoid Breakouts if a common power feed is used: 18 AWG (1.024mm)

between the PD Board and the Analog and/or Solenoid Breakouts if individual power feeds are used: 20 AWG (0.8128mm)
between the PD Board and the cRIO: 20 AWG (0.8128mm)
between the PD Board and the wireless bridge: 20 AWG (0.8128mm)
between the PD board and 5A custom circuits: 20 AWG (0.8128mm)

pneumatic valves: 24 AWG (0.5106mm)


The branch circuit may include intermediate elements such as COTS connectors, splices, COTS flexible/rolling/sliding contacts, and COTS slip rings, as long as the entire electrical pathway is via appropriately gauged conductors.

Wires that are originally attached to legal devices are part of the device and by default legal as supplied. Such wires are exempt from Rule [R44].

There's no such rule about Jaguars or Victors. The size of the wire depends solely on the breaker you use. You can even wire the Jaguar or Victor to a CIM using 18 AWG wire, as long as you use the appropriate breaker. I wouldn't recommend it, but the whole rule with the wire size is to protect the circuit (wires and power switching devices).

It is for the same reason, I recommend that team DO NOT TIN wires for use in the Wago terminal blocks. Any procedure that forces a round shape to anything inserted in the terminal reduces the contact area to a fraction of that achieved by bare wire. This significantly raises the contact resistance. For that reason I recommend you do not use solid wire or any of the terminations discussed above.

Agreed completely.

Tinning wires should not be done on the robot in any case that I can think of. If your team would like, you can solder ring/fork terminals, or the male/female disconnects, only after crimping the connection first. This gives you the best contact area (copper to tinned copper connector casing + copper to solder to tinned copper connector casing. Doing this will also remove any chance that it could vibrate out if soldered correctly. I've done this in the past, but I do not recommend it unless your team has plenty of time to do it. You have to remove the plastic sheathing on the connector, flux the connector, heat the entire connector to the solder's melting point, and flow the solder in the connector. It will take about 5 minutes of preparation, soldering, and cleaning up per connector. You should clean off the remaining flux as it will corrode the metal. You also need to insulate the connector, which would require (recommended) heat shrink, which should be slid on before soldering, or electrical tape.

For the solid wire. Here's my input: Don't use it on the robot at all. Solid core wire is not designed for mobile applications. It does not crimp well, and does not handle vibrations, hits, or bends very well at all. Leave it out of your design completely. Excessive bending will break the wire. If you were to use it on the robot, do not use it on anything that moves, as it will break down over the course of the competition.

[WizenedEE]

The gauge of the wire you should use depends solely on the circuit breaker; that's for safety. See [R44].

The amount of current your motors will draw really depends on which motor you're using and how you're using it. For example, last year we used 20 amp breakers with our window motors because their stall current was 21 amps. However, for CIMs on the drivetrain or other high-load applications, you'll definitely be at a disadvantage with 30 amp breakers.

Of course, you can also mix and match breakers; so you could buy just a bit of 12 gauge wire for the drive train and use 16 gauge wire for your light duty things.

[Al Skierkiewicz]

jessica,
There is some misconceptions in this thread so I will try to clear them up. One, the size of the breakers is strictly tied to the wire being used. The breaker protects the wiring and the rules are written strictly for that reason. There is no current requirement for the Jaguar or the Victor, they actually use very little of the input current, passing virtually all of it to the motor that is connected to the output. A smaller breaker does not pass less current than a higher rated breaker does. If you exceed the current, it will trip and then reset. If you can't get larger wire then it is perfectly acceptable to use #14 with the 30 amp breaker. On larger motors you will likely trip often and your performance will suffer. Any Home Depot, Lowes or any hardware store sells wire by the foot in any color you need. I suggest (most people read that highly recommend) that larger motors like the CIM and FP actually be fed with #10 and a 40 amp breaker. If you position the speed controller near the motor it is controlling, then you can connect the motor wires directly to the controller output terminals. CIM motors are supplied with high temperature #12 and can be powered from a 40 amp breaker.
As a second hint, when crimping terminals, always perform a 'tug test'. That is to say after you crimp a terminal to the wire, pull on the terminal as hard as you can. If you can't pull it off, it should be good. If you do throw it away and try again.

[engunneer]

Originally Posted by Al Skierkiewicz

As a second hint, when crimping terminals, always perform a 'tug test'. That is to say after you crimp a terminal to the wire, pull on the terminal as hard as you can. If you can't pull it off, it should be good. If you do throw it away and try again.

When I teach the tug test to students: "Well if it comes off, you have to redo it anyway"

Also make sure you are tugging hard enough. If you can get to arm shaking level while tugging, then it is ready for competition.

My last crimping hint is to buy a good crimper. The one that comes in the kit is functional, but it's harder to make a crimp that passes the tug test. something like Mcmaster #69555K62 is 10 times better than something like #7007K92.

@Al, Are wire ferrules (7950K28) in the terminal blocks allowed? I don't see anything in the rules one way or the other.

[Al Skierkiewicz]

Brandon,
Are you asking if these are legal for use in the Wago terminals? If so, there is no rule against it. However, these are not recommended by the manufacturer. Stranded wire in the Wago terminal is expected to flatten when the Wago terminal is allowed to close. This causes a significant increase in the surface area of the wire promoting low contact resistance and less heating. The only ferrule recommended by Wago is predictably a Wago product which has a rectangular cross section.
It is for the same reason, I recommend that team DO NOT TIN wires for use in the Wago terminal blocks. Any procedure that forces a round shape to anything inserted in the terminal reduces the contact area to a fraction of that achieved by bare wire. This significantly raises the contact resistance. For that reason I recommend you do not use solid wire or any of the terminations discussed above.

[engunneer]

My crimper for those ferrules results in a square cross section. I use them in cage-clamp style terminal blocks for work normally. Raw stranded will still probably end up with more contact area, but the ferrules are harder to pull out. I will compare the ferrules I have against the Wago ones to see how they compare. Thanks for the hint.

--Branden

Edit: A quick look at Wago's catalog shows basically the same ferrules.

To get this post back on-topic:
Wires inserted into the power distribution terminals should also be subjected to a pull test!

[Doc543]

you can use the BDC-COMM program (the same one you use to upgrade the Jag firmware) to test the motors, it can also give you exactly how much current a motor is pulling. I know that in Java you can get the Jags to tell you the current of the motor through the CAN bus.

[imjessica]

Originally Posted by engunneer

When I teach the tug test to students: "Well if it comes off, you have to redo it anyway"

Also make sure you are tugging hard enough. If you can get to arm shaking level while tugging, then it is ready for competition.

My last crimping hint is to buy a good crimper. The one that comes in the kit is functional, but it's harder to make a crimp that passes the tug test. something like Mcmaster #69555K62 is 10 times better than something like #7007K92.

@Al, Are wire ferrules (7950K28) in the terminal blocks allowed? I don't see anything in the rules one way or the other.

you have to pull it that hard? would it be easier to use electrical tape because we don't even have a crimping tool yet. also @al thanks that was a really helpful answer

[RyanN]

Originally Posted by imjessica

you have to pull it that hard? would it be easier to use electrical tape because we don't even have a crimping tool yet. also @al thanks that was a really helpful answer

I'd say pull hard with your pinky finger. If it doesn't come out, you're probably fine. Don't use electrical tape to keep the connection in. Without it being crimped, the connection is subject to high resistance, which will overheat the connector. Electrical tape should ONLY be used for insulation purposes, and NEVER to hold a wire in place.

[Al Skierkiewicz]

Jess,
You have to apply enough pull to simulate what might happen on your robot. You are going to use crimp on (solderless) terminals for all wiring to and from your speed controllers. There is no other way to have a reliable connection. Tyically, you will strip about 1/4" of the insulation off the end of the wire or what ever the suggested strip length for the connector you are using. Insert the wire and crimp. The latching crimp tool works best as itwill not allow you to remove it until the correct amount of force has been used. Most of my students have a hard time in the beginning of the season because they lack forearm strength. By ship day, most will do it with one hand.

[imjessica]

Originally Posted by Al Skierkiewicz

Jess,
You have to apply enough pull to simulate what might happen on your robot. You are going to use crimp on (solderless) terminals for all wiring to and from your speed controllers. There is no other way to have a reliable connection. Tyically, you will strip about 1/4" of the insulation off the end of the wire or what ever the suggested strip length for the connector you are using. Insert the wire and crimp. The latching crimp tool works best as itwill not allow you to remove it until the correct amount of force has been used. Most of my students have a hard time in the beginning of the season because they lack forearm strength. By ship day, most will do it with one hand.

yeah im probably to weak to crimp it right but this guy on my team pressed it so hard the ternimal was completely flat but the wires still came out pretty easily. idk what were doing wrong. im not sure we have the right tool though,did it come with the kit? if not, which model would you recommend?

[Al Skierkiewicz]

If the terminal was flat but the wires still pulled out, the terminal likely was too large for the wire. The terminals are color coded for ease of use. Red for #18-#22 wire, Blue for #16-#14 and yellow for #12-#10.
If you were using the crimper that comes in the KOP, that crimper is designed for uninsulated terminals. It can be used for insulated terminals if one is careful. In either case (insulated or non-insulated), please note there is a concave part of the tool and mating bump on the other side of the jaw. When you set the terminal in the crimper, note that the terminal is merely a flat piece of metal that has been formed into a cylinder. The slit or open side of the terminal must be placed in the concave portion of the tool. If you set the terminal into the tool with the slit facing the bump, the bump will push open the slit and release the wire. If you are using insulated terminals, I suggest you purchase a crimp tool designed for those terminals.