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Unread 14-03-2005, 14:30
meaubry meaubry is offline
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Re: PWM cables: too fragile? what fixes/precautions?

We have had a lot of problems with these connections. So far I have had to replace 3 pwm cables and 1 speed controller. The alignment of the connector is very very difficult, if not impossible. Be careful if you do decide to help the situation by cutting or filing the corners (provide relief) as the plastic may fall into the connector hole. We found some clips that slide in over the connector once they are seated and under the speed controller body - problem is that we have the speed controllers velcro'd down so they won't move around.
Still looking for a better way than hot glue to keep those little buggers from coming out as easily.
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Unread 14-03-2005, 14:57
Rick TYler Rick TYler is offline
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Re: PWM cables: too fragile? what fixes/precautions?

Quote:
Originally Posted by Rick TYler
We had so much trouble with the PWM cables plugging into the Victors that we now have a team member who is the designated Cable Guy. He plays the piano and has long, thing fingers. First time every time. We'll be glad to rent him out for tournaments for a modest donation to our '06 campaign fund...
Replying to my own post. How lame is that...?

We had our arm not operate TWICE during the tournament when someone other than our Designated Electronics Guru and Cable Guy tried to plug in a PWM cable. We lost both of these rounds, but found out that we could really play defense. It was kind of fun watching our modest little wooden bot keep a 12-foot topper from scoring a single tetra, even if we still lost the match.

Of course, the real failure was that we did not detect the bad connection before the match. We bad, the 'bot was sent out to the field without a complete systems check first. This will NOT happen again next year. Note to self: if anyone is working on the robot, the electronics Guru will be the only one allowed to touch the hardware.

A team at Portland (I forget the number, but it was Santiam Christian School's team) said that they put a tiny dot of silicone adhesive on the connector after it is seated. They say the silicone is easy to remove, but grips just enough to prevent accidents.
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Unread 14-03-2005, 15:09
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Re: PWM cables: too fragile? what fixes/precautions?

We have had problems with pwm cables before, especially last year with the current sensor. It was wired to keep the globe the drives our "fingers" from snapping it's sprockets and the 5/16" fiberglass rod that made up the fingers.
The connection would get noisy and finger movement became very intermittent and unpredictable. The fix for us was a can of ProGold G5 contact treatment. Sprayed on the free ends of cables and then gently run in and out of the sockets or pins a few times. This seemed to cure all of our PWM and current limiter issues. This year we will be treating all pwm cables before driving as a Standard op.
We will be at Buckeye and West Michigan if you need some I will lend you the use of a can. BTW if your on the west side of michigan you can get it at SF electroncs. Not cheap but good stuff.
Tom Cooper
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Unread 14-03-2005, 17:34
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Re: PWM cables: too fragile? what fixes/precautions?

Our pwm cables never failed us. The little burs on the side of the pwm insert on the victors are for keeping the pwm cables inside so it doesn't move. If you give the cable some wiggle room and keep it out of moving parts, the cable should be fine.

But when pwm cables do come out, its NOT a good thing, because those wires are live and if it touches metal, you're creating a short that goes right back to the RC, which is terrible. A fried RC is about as bad as it gets electronics-wise.
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