Wiring a Fisher Gear Motor
 

Hello Everbody,

I represent Team 1748, and we need help wiring.

Do anyone know how to wire a fisher price motor.
We would also like to know what gauge key to use for a victor or a jaguar.

We appreciate the help for this.

Re: Wiring a Fisher Gear Motor
 

I don't know how much you know, so I'll give the info in whole.
Victor/Jaguar depends on if you want it to just be on and off or if you need fine control over it. A Victor works well enough for digital control (such as a button on a game controller), but a Jaguar is more useful for throttling. I trust 14 AWG wire for most of our motors, and I believe a 20 amp breaker (although I would have to check it's not 30). The motor itself attaches to small female connectors, but it's notoriously a loose connection. Make sure the connectors are new and fit tightly (you may also want to tape them on).
That's all I can say towards wiring it.
Sorry about the other question.

Re: Wiring a Fisher Gear Motor
 

You have to refer to r44

Application Minimum wire size
40A circuit 12 AWG (2.052mm)
30A circuit 14 AWG (1.628mm)
20A circuit 18 AWG (1.024mm)

With that said, I would recommend soldering wires to the terminals of the fisher price motor. I find it difficult to put 12 gauge wire on the terminal and I usually use 14AG and 30 amps for the FP.

Re: Wiring a Fisher Gear Motor
 

I think you are confusing the victor 884 with a spike relay. The victor 884 does have effective variable speed control.

Re: Wiring a Fisher Gear Motor
 

Avoid soldering unless you're confident you can do so without damaging the motor brushes. The heat spread into the motor tabs by soldering could easily damage the brushes and reduce motor performance. Try using 3/16" quick disconnects with hot glue and appropriate stress relief for the wires.

FPs can easily draw up to 40A. Select the fuse and corresponding wire gauge as is appropriate for its application.

Re: Wiring a Fisher Gear Motor
 

I know it does, but we only put Victors on analog motors that we use in a digital manner, because the Jaguars are more precise.
Spikes are for strict digital-only.

Re: Wiring a Fisher Gear Motor
 

Triga,
The FP motors have a smaller terminal than that used for other electrical connections on the robot. I believe they are 3/16" instead of the 1/4" used for other devices like the Spike. Soldering is recommended to keep the terminals or wiring in place but it requires an experienced person to do so. The FP (and other motors) have an internal thermal circuit breaker. In the FP motor, this protection device is connected directly to the terminals. Soldering can pull this assembly out of alignment inside the motor and make it fail.
We use a flag terminal of the proper size, soldered to the end of the motor wire. Then after scraping the motor terminal to remove the protective film, we push the terminal into place and solder the terminal to the motor. We follow this with a piece of heatshrink tubing and then bend the wires down along the side of the motor and using a wire tie, secure them in place. Any tug or vibration on the motor wire is likely to fatigue the motor terminal without this secondary strain relief.

Re: Wiring a Fisher Gear Motor
 

What do you mean by "more precise" ?

Re: Wiring a Fisher Gear Motor
 

We just trust the Jaguars more for running things like the drive and shooter motors because we like the performance a little more than the Victors, but precise could have been poor word choice.

Re: Wiring a Fisher Gear Motor
 

Not to go off-topic, but there are many who regard the Victors as a higher performance product in various ways. No CAN though, of course.

Re: Wiring a Fisher Gear Motor
 

In what various ways would Victors be "higher performance" than Jags?

Re: Wiring a Fisher Gear Motor
 

There were posts last year about the output curve of the Jaguar not being as smooth as the victor, giving bad output to the Window Motors, if I remember correctly. And making a victor go bad is quite difficult.

Re: Wiring a Fisher Gear Motor
 

Theoretically lower on-resistance (though not a significant difference).
Smaller and lighter for the same basic power capability.
No built-in restriction on current draw, letting systems push the boundaries of ultimate capability before failure.
The slower PWM output of a Victor actually helps certain mechanical systems to work better at slow speed.

Re: Wiring a Fisher Gear Motor
 

The Jag's output curve is just as "smooth" and far more linear than the Vic's, as can be seen here. The putative compatibility problem of Jags & window motors has been widely discussed but the underlying cause not definitively understood AFAIK.

The higher PWM output frequency of the Jag causes somewhat less motor heating (for the same output torque) compared to the Vic, for some motors at slow speed.

I guess we are using a different vocabulary. In engineering parlance, that's not a performance issue, it's a reliability issue. Handled properly (read: don't pack them full of metal shavings and don't reverse the battery polarity... reasonable expectations) and used in a properly-designed system, black Jags have had a good reliability record for many teams.

Re: Wiring a Fisher Gear Motor
 

The deal with Jags and Window motors is that the Jags output at a higher frequency (http://www.chiefdelphi.com/forums/sh...8&postcount=14). The jags actually have a smoother output curve than Victors. The Vics have relatively few discrete steps (http://www.vexforum.com/showthread.php?t=20350)

Also, note that FPs are required to be controlled by a Jag or a Victor (NOT a spike). R50a.

Re: Wiring a Fisher Gear Motor
 

OK,
Time to correct some items here.
1. The Victor has a lower switching frequency which does not react to motors with a higher winding inductance. It is this interaction which gives the Jaguar it's seemingly more linear response.
2. When used with PWM, both controllers have the same limitations in discrete steps. The max being ~127 in each direction less whatever deadband is in use. The hobby/servo PWM standard provides for this step count.
3. The Jaguar seems to react with the locking pins in the window motor. While documented, there is no real study of what is actually occurring. My personal opinion is that the switching frequency causes the pins to vibrate and alternately lock in place while the motor is driving.
4. The Jaguar uses FETs with lower "on" resistance but in the newer devices has reduced the parts count to two per leg instead of three. I will have to search back through my files but as I remember the Victor is 0.006 and the Jag is 0.004 ohms series resistance.
5. The Jag uses current sense and under internal software control will disable output when the current exceeds a set point. See the Jag spec sheet for details. The Victor does not sense current so the very small resistor used in the Jag is not present in the Victor.
5. Size is self explanatory.
6. The Victor does not have CAN at the present time. Customers have been asking for it.
7. Neither device has reverse polarity or output protection.
8. The Jaguar requires a very short reverse pulse when at full throttle to keep the bootstrap cap charged. It does not affect the available output power.

Re: Wiring a Fisher Gear Motor
 

Thanks for the link. We were wondering why our new drivetrain is so phenomenally easy to drive (same layout as last years bot, but controlled by black Jags). I no longer see any reason to use Victors.

Re: Wiring a Fisher Gear Motor
 

FYI:

If you find yourself using Vics and are unhappy with the output response curve, you can adjust the joystick values to compensate:

http://www.chiefdelphi.com/media/papers/2421

Re: Wiring a Fisher Gear Motor
 

Thanks for all the discussion about Jaguars and Victors, but that's a good topic for another thread. I hope we can wrap this up now.

P.S. - Another reason I prefer the Jaguars for our drive and shooter motors is that we are running CAN to them, which shawnz brought to my attention again.