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-   -   Servo Connector duty cycle (http://www.Wattflyer.com/forums/showthread.php?t=73138)

rags 02-04-2014 12:45 AM

Servo Connector duty cycle
 
I have searched for this but I've been unable to find anything on this. What is the duty cycle of servo connectors? Assuming reasonable or common care when plugging in and in plugging servo connectors, when can we expect to see a failure? I realize so many variables are involved but please share your thoughts and suggestions for alternative connectors.
Application could be wing attachment to Rx flight pack.

Thanks

fhhuber 02-04-2014 01:37 AM

Generally you break the wires at the crimp before the connectors don't work.

Hundreds of connect/disconnect cycles. But its highly dependent on how you do it.

kyleservicetech 02-04-2014 01:37 AM

Quote:

Originally Posted by rags (Post 939117)
I have searched for this but I've been unable to find anything on this. What is the duty cycle of servo connectors? Assuming reasonable or common care when plugging in and in plugging servo connectors, when can we expect to see a failure? I realize so many variables are involved but please share your thoughts and suggestions for alternative connectors.
Application could be wing attachment to Rx flight pack.

Thanks

These pins are (or should be) gold plated for quality connectors. That said, that gold plating is extremely thin, like millionths of an inch thick. All it takes is perhaps a hundred insertions to wear it off. The important issue is physical wear of that connector. It would take a long time, but suppose it could happen. Eventually.

On the other hand, if the pin is repeatedly inserted, like in a wing connector, the act of sliding the connector together and apart is sort of a self cleaning operation.

That gold plating gets important when you've got a servo extension cable buried inside a wing that doesn't get touched for a year or three.

kyleservicetech 02-04-2014 01:42 AM

Quote:

Originally Posted by fhhuber (Post 939119)
Generally you break the wires at the crimp before the connectors don't work.

Hundreds of connect/disconnect cycles. But its highly dependent on how you do it.


Yeah, pulling the connector out of the receiver by yanking on the connector wires is a real NO NO.

rags 02-05-2014 06:35 PM

Great info thanks. So to summerize, a little slack so as to not pull on the Rx, strain relief and a lot of care disconnecting, and expect to eventually see a failure.
Now how about alternatives? Multiplex plug? What else is out there so we aren't plugging and unplugging these connectors?

Thanks

Quote:

Originally Posted by kyleservicetech (Post 939121)
Yeah, pulling the connector out of the receiver by yanking on the connector wires is a real NO NO.


fhhuber 02-05-2014 07:01 PM

With reasonable care in plugging/unplugging you can get MANY years from the standard servo connector...

If I had RXs they would fit I still have good Futaba FG series servos and the plugs are fine. The pins are the same but spaced different and opposed male-female vs modern. This connector was discontinued about 20 years ago. You can't even buy the adapter cable now.

kyleservicetech 02-06-2014 01:09 AM

Quote:

Originally Posted by rags (Post 939254)
Great info thanks. So to summerize, a little slack so as to not pull on the Rx, strain relief and a lot of care disconnecting, and expect to eventually see a failure.
Now how about alternatives? Multiplex plug? What else is out there so we aren't plugging and unplugging these connectors?

Thanks

If you're into making your own cables, www.digikey.com sells a connector with locking tabs. IMHO, this would only be useful if you've got a model with ailerons and flaps in each wing panel. With this connector, the cable between the wing and receiver can be built up with non-identical connectors for the left and right panels. I've got mine set up with one connector for the aileron/flaps for each wing panel. You still have to use the standard servo connectors for the receiver end, and the servo end though.

This locking connector is reasonable in price, and is available in pin counts from two pins to 20 pins or so. Gold plated pins are also available.

Take a look:
http://www.wattflyer.com/forums/showthread.php?t=64209

In fact, I've also standardized on this connector for all of my A123 battery pack balance cables.

rags 02-06-2014 06:27 PM

Thank you. - I like it. Do you add anything for strain relief?

I just read an article written by Chris Hansen in Dec of 2012 and he indicated up to 50 cycles for non gold plated and 50 to 100 cycles for gold plated. He stated the non gold plating wears and oxidation begins thus restricting current. Then of course there is the whole issue of wire flex and subsequent breakage.

Again thank you for your thoughts.
RG

Quote:

Originally Posted by kyleservicetech (Post 939290)
If you're into making your own cables, www.digikey.com sells a connector with locking tabs. IMHO, this would only be useful if you've got a model with ailerons and flaps in each wing panel. With this connector, the cable between the wing and receiver can be built up with non-identical connectors for the left and right panels. I've got mine set up with one connector for the aileron/flaps for each wing panel. You still have to use the standard servo connectors for the receiver end, and the servo end though.

This locking connector is reasonable in price, and is available in pin counts from two pins to 20 pins or so. Gold plated pins are also available.

Take a look:
http://www.wattflyer.com/forums/showthread.php?t=64209

In fact, I've also standardized on this connector for all of my A123 battery pack balance cables.


fhhuber 02-06-2014 06:44 PM

If its just 50-100 cycles I have some planes that should have crashed at least 5 years ago... that's just one year's taking off and putting on the wings at the field. I sometimes go through 20+ connect/disconnects of a servo while setting up the aircraft before its first flight.

kyleservicetech 02-07-2014 12:40 AM

Quote:

Originally Posted by rags (Post 939340)
Thank you. - I like it. Do you add anything for strain relief?

I just read an article written by Chris Hansen in Dec of 2012 and he indicated up to 50 cycles for non gold plated and 50 to 100 cycles for gold plated. He stated the non gold plating wears and oxidation begins thus restricting current. Then of course there is the whole issue of wire flex and subsequent breakage.

Again thank you for your thoughts.
RG

That connector, along with the standard servo connector terminals provide wire strain relief as part of the crimping process.

What is absolutely dangerous with this sort of stuff is a terminal or other item that is simply soldered to a wire, without providing strain relief of that soldered connection. What happens is the solder flows under the wire's insulation, making that portion of the wire as flexible as a coat hanger. Just bend it back and forth once or three times, and that wire can break off completely. (Take a look at your 2.4 Ghz receiver antenna connections! They'd better have shrink tubing strain relief)

We had a lot of troubles with wires soldered to circuit boards at work years ago, with more than a few $$$$ spent in warranty repair. We actually had these wires break off during shipping of the 200 pound control cabinet to the customer.

Because of this issue, our design engineers made it mandatory that each and every wire leading from a circuit board had to have strain relief as part of the design. What was usually done, was to insert the wire and insulation through a dummy hole in the circuit board. Then the wire was soldered to the appropriate place on the other side of the circuit board. Crude, but it was very effective. The wire breaking off problem was totally eliminated.

FYI, just slapping on some electrical safe RTV type material didn't work anywhere near as well as the hole through the board technique.

FYI, I started another thread, based on your original question on those servo connectors as below:
http://www.wattflyer.com/forums/show...367#post939367


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