1771's Jaguars

[mikelowry]

They're so cute

[RMS11]

Pic link is broken for me :/

[dodar]

So did you guys buy the black jags?
what is gthe difference between the black ones and the gray ones?

[R.C.]

Originally Posted by dodar

So did you guys buy the black jags?
what is gthe difference between the black ones and the gray ones?

I believe you have to have one of the black jaguars to use CAN.

-RC

[mikelowry]

We bought the black jaguars for 2 reasons.
1 You have to have a black jag to start the can bus.
2 we needed to buy 4 more jaguars this year and decided that for only 7 more dollars apiece we could have 4 jaguars that worked better, looked cooler, and could run a can bus.

If we break any of our gray jags this year we will be replacing them with black ones.

Here is the link in case you cant see the picture

http://picasaweb.google.com/nghs1771...11624392842818

[MrForbes]

ahhhh....there's that pesky picture. When you use the img tags, you need to make sure your image link ends with .jpg, or else we might not be able to see it.

[mikelowry]

Originally Posted by squirrel

When you use the img tags, you need to make sure your image link ends with .jpg, or else we might not be able to see it.

I see. Thanks for the advice

[Tanner]

Interesting little connectors on the wires, what are those? They seem like they would be very helpful in keeping the control panel all nice and neat.

-Tanner

[MrForbes]

They look like the power connectors commonly used on RC cars. Might also look into the smaller sizes of Anderson Powerpole connectors, they don't have the exposed contacts.

[apalrd]

I would not recommend using a connector such as that on both the input and output side of a Jaguar, or any speed controller. You add resistance and another point of failure. Run all wiring directly from the PD board to the Jaguar, then from the Jaguar directly to the motor. If the motor has built in leads, crimp on a quick connect there and only there. The only exception is if a large portion of your robot must be removable, then having mass quick-connects or a terminal block there would help. It isn't that hard to screw in a fork terminal, so having those connectors provides no advantage. If you plan on re-using the Jaguars from year to year, you can always unscrew the fork terminals and pull it out, it's not that hard.

It isn't clear to me if the Black jaguars are actually a better product, but after the problems last year my team is only buying Victors. We will use the Jaguars that come in the kit, but no more. All Jaguars can handle CAN, so having more than 1 Serial-CAN Black Jaguar isn't helpful. The do look nicer, but when they're buried in the chassis, do looks really count?

[Jon Jack]

The connectors in the picture are 'Deans Connectors'. They're used in RC cars. We used them all through last year and had no problems with them. Dean's Connectors are about 1/3 the size of the power pole connectors and have a higher current rating. IRC the Dean's Connectors were rated to 80A, whereas the power poles are rated to 30A.

[apalrd]

Originally Posted by Jon Jack

The connectors in the picture are 'Deans Connectors'. They're used in RC cars. We used them all through last year and had no problems with them. Dean's Connectors are about 1/3 the size of the power pole connectors and have a higher current rating. IRC the Dean's Connectors were rated to 80A, whereas the power poles are rated to 30A.

There are also Power Pole's rated for 45 amps, and larger Power Poles connectors for 50, 175, and 350 amps. We use some for our robot batteries. (the 50 amp kind, actually) We have also used simple quick-connects in many places and screw-terminal blocks when a large number of connections are necessary, without any problems. There are power poles to handle more then 30 amps.

[Al Skierkiewicz]

Guys,
I would need to see the actual tested ratings for these connectors. None appeared in the link above. Although the 35 amp Power Poles would seem a bad choice remember the Power Poles are rated for continuous duty at that current. Have you noticed that the battery is only a 50 amp Power Pole? The two minute (say up to ten minute) rating for these connectors far exceeds the failure point of 35 amps continuous. In case you haven't tried, Power poles are easy to solder but if you use the West Mountain crimper, with #10 wire your connector resistance is already very low. If you solder, it is almost the same resistance as a wire. A bad crimp on any connector (or a solder job that only covers part of the wire) will get hot under load. Inspectors need to have numbers. You may have been able to get away with them in the past but if they are under rated, then you will need to change.
As stated earlier, I recommend using the least number of connections you can. We use Power Poles on motors (and in special applications) only to allow their rapid removal. Everything else is point to point.

For reference...
CIM Stall Current is 129 amps
Fisher Price Stall Current is 70 amps
Battery (charged) is capable of over 600 amps.

[martin417]

Originally Posted by Al Skierkiewicz

Guys,
I would need to see the actual tested ratings for these connectors. None appeared in the link above. Although the 35 amp Power Poles would seem a bad choice remember the Power Poles are rated for continuous duty at that current. Have you noticed that the battery is only a 50 amp Power Pole? The two minute (say up to ten minute) rating for these connectors far exceeds the failure point of 35 amps continuous. In case you haven't tried, Power poles are easy to solder but if you use the West Mountain crimper, with #10 wire your connector resistance is already very low. If you solder, it is almost the same resistance as a wire. A bad crimp on any connector (or a solder job that only covers part of the wire) will get hot under load. Inspectors need to have numbers. You may have been able to get away with them in the past but if they are under rated, then you will need to change.
As stated earlier, I recommend using the least number of connections you can. We use Power Poles on motors (and in special applications) only to allow their rapid removal. Everything else is point to point.

For reference...
CIM Stall Current is 129 amps
Fisher Price Stall Current is 70 amps
Battery (charged) is capable of over 600 amps.

Al,

For reference, I find that quite often, published specs are misleading, and in some cases outright wrong. I did a great deal of research with the CIM motor over the last year (not FIRST related). While the data around the higher efficiency end of the curve is reasonably accurate, as you get farther from that point, it goes off into the weeds. Using accurate instrumentation, I measured the current at several different operating speeds and loads. I was using a 95 AH AGM 12V battery with an internal resistance much lower than the FIRST batteries. I don't remember exactly how high the current got at its highest, but it was very near 30 Amps, no more than 35. That was when the motor was nearly stalled. At stall, the draw dropped to less than 30 amps. Not sure why the data sheet says what it does, but the CIM doesn't draw 129 amps.

Based on that, and the fact that Fisher Price toy cars (the main use of the FP motors) are wired with ~14 gauge wire, I don't believe the 70 amp rating on them. I know my kids were able to stall the motors out on the jeep they drove around, and no wires smoked.

[sanddrag]

Originally Posted by martin417

I don't remember exactly how high the current got at its highest, but it was very near 30 Amps, no more than 35. That was when the motor was nearly stalled. At stall, the draw dropped to less than 30 amps. Not sure why the data sheet says what it does, but the CIM doesn't draw 129 amps.

I find this very hard to believe. We have known and trusted and designed to these specs for 9 years now. For the CIM to stall at less than 40 Amps, would mean its peak power is significantly less than published, yet our robots seem to perform to expectations every time.

To be honest, I've never run one through any sort of current measuring device, but I certainly have tripped 40 Amp breakers with them. I know some teams have done current monitoring (and if I recall, some sort of FIRST-sponsored program at IRI 2008?). Do any teams have any current draw data they'd like to share?