Problem with the jaguar wire

[tahreer]

hey..
We have this case during tests …the wire witch connected
from the power distributor to the jaguar … suddenly becomes too hut... I wonder if anyone knows why that happens???
thanx...

[seannoseworthy]

Did you have the jaguars wired properly I.e. black wire to the black power screw, if you reversed you power and motor connections the jaguar is fried and the warranty is voided. I just re-read that if you mean the wires between the PD and the Jaguar got hot. You should be using 12 AWG wire with a 40 amp breakers for the CIM's and 30 amp breakers for smaller motors.

[Al Skierkiewicz]

Originally Posted by tahreer

hey..
We have this case during tests …the wire witch connected
from the power distributor to the jaguar … suddenly becomes too hut... I wonder if anyone knows why that happens???
thanx...

Tahreer,
Please check the wire size requirements. If the Jaguar is working and the motor it controls is moving, your wire size is too small. If the jaguar is not working, it is connected backwards or has failed. Metric wire size has been included in this year's robot rules to make it easier for teams outside the US.

A. 12 AWG (2.052mm) or larger diameter wire must be used for all circuits protected by a 40A circuit breaker.
B. 14 AWG (1.628mm) or larger diameter wire must be used for all circuits protected by a 30A circuit breaker.

[Jon Stratis]

Originally Posted by tahreer

hey..
We have this case during tests …the wire witch connected
from the power distributor to the jaguar … suddenly becomes too hut... I wonder if anyone knows why that happens???
thanx...

Since others have already addressed the most likely root causes (wire is too small or the Jag is blown), i figured i'd chime in and answer your actual question - why that happens.

Every wire is really a resistor, although the resistance is usually extremely small. As you try to pass electricity through any resistor, you end up with some loss - all the power doesn't make it to its destination. That's because it takes effort to push the electricity through the resistance, and that effort is lost as heat. It's this basic principle that lets things like incandescent light bulbs work - they use a filament with high resistance to generate a lot of excess heat. So much heat, in fact, it glows.

Now, imagine your typical stranded wire used on the robot. Each strand in the wire has some small resistance. When you have multiple strands of wire running in parallel (forming a single wire with insulation around it - hence the stranded wire name we give it), the wires act as resistors in parallel, which end up reducing the overall resistance of the system - the reciprocal of the equivalent resistance is equal to the sum of the reciprocal's of the individual resistances. See http://en.wikipedia.org/wiki/Series_...allel_circuits for more details on how this works.

So, when you have a small wire, with only a few strands, your resistance is much higher than a larger wire with many more strands. If your wire is too small for the amount of power sent through it, it will start to get very hot. In some cases, this could cause insulation to melt or start an electrical fire. Even larger wires can get warm if you approach the rated limits for that gauge wire.

So, now that you know why the wire if hot, you can do what everyone else already suggested and replace it with an appropriate gauge wire!