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Old Mar 24, 2015, 06:59 AM
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OK to relocate a ferrite ring ?

Setting up the ESC I find that the throttle cable with the ferrite ring is restricting the routing of that wire.

Is it OK to relocate the ferrite ring approx. 1 or 25mm back along the cable towards the ESC.

The ESC is a Turnigy AE-45A

Thanks
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Old Mar 24, 2015, 07:03 AM
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I don't see any reason why it would matter where on the wire the ring is. It is there to keep electrical noise from the ESC out of the power for your receiver. If anything I would think it would ideally be as close to the ESC as possible.
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Old Mar 24, 2015, 07:28 AM
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Thanks

I did not know what the reason for it is so as you say I shall put it closer to the ESC
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Old Mar 24, 2015, 12:06 PM
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Is a toroidal ring even necessary anymore with brushless systems? There's no RF noise being put out by the brushes cuz there ain't none.

mw
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Old Mar 24, 2015, 04:21 PM
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Ever since I converted over to 2.4GHz I've taken all the rings off my ESCs and BECs. Never noticed any problem running like that.
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Old Mar 24, 2015, 06:13 PM
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The commutation is still taking place and there is plenty of noise generated by that. Any time you have square waves, inductors and high current, you will have electrical noise. Even 3.2 GHz receivers are susceptible to glitches on the power bus. Just because they respond to them a little more gracefully is no reason to stop avoiding them.
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Old Mar 24, 2015, 07:55 PM
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Quote:
Originally Posted by clive_fox View Post
Setting up the ESC I find that the throttle cable with the ferrite ring is restricting the routing of that wire.

Is it OK to relocate the ferrite ring approx. 1 or 25mm back along the cable towards the ESC.

The ESC is a Turnigy AE-45A

Thanks
I'd suspect those ferrite rings are used for the radios running on 72 Mhz, or what ever frequencies are used in your location.

These 2.4 Ghz radios are far less susceptible to RF (Radio Frequency) noise than the 72 Mhz units.

If you have any question, run a range check with the ferrite ring in its present location, then move it to where you'd like, and re-check range. If you don't find any difference, that's your answer.
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Old Mar 24, 2015, 09:51 PM
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Thanks that makes perfect sense
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Old Mar 25, 2015, 01:16 AM
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The ring is an inductor, essentially in series with the leads coming from the ESC. As such it does not matter where on the wire it is. The important thing is to make sure it stays in the circuit.

Volrathd, as stated in my above post, the ring is protecting against glitches on the power rails not from RF interference. While the 2.4 GHz radios are able to find their signals amongst all the RF interference around them, they are still just as susceptible to power line glitches as any other receiver. I would most certainly not remove the ring.
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Old Mar 25, 2015, 09:41 AM
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Then why do most BL ESCs not come with a toroid and work just fine?

mw
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Old Mar 25, 2015, 11:12 AM
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Ferrite Rings?

Quote:
Originally Posted by Mike Dubovsky View Post
The ring is an inductor, essentially in series with the leads coming from the ESC. As such it does not matter where on the wire it is. The important thing is to make sure it stays in the circuit.

Volrathd, as stated in my above post, the ring is protecting against glitches on the power rails not from RF interference. While the 2.4 GHz radios are able to find their signals amongst all the RF interference around them, they are still just as susceptible to power line glitches as any other receiver. I would most certainly not remove the ring.
I've conducted many tests on the "Power Line Glitches" for my Spektrum line of 2.4 Ghz receivers. The results show that it takes a minimum of a 0.7 Millisecond voltage sag on these receivers to cause a re-boot of the receiver. Voltage sags of less than 0.7 ms had zero effects on my various collection of Spektrum receivers.

Spektrum Receiver Voltage Sag Tests
http://www.rcgroups.com/forums/showthread.php?t=2351423

Those ferrite rings do not have the capability of "Cleaning Up" a 0.7 ms voltage sag.

Something else might be involved here. That would be some of those old receiver switches we all use on our radio systems. I also did some testing on some of my 10-15 year old switches recently. The results were so disturbing, I cut the wires off of those old switches so they will NEVER be used in any of my models. All three of my old switches had contact resistance of over one ohm. Enough to cause a crash. After sliding the switches back and forth several dozen times, their contact resistance dropped to around 0.1 Ohms, more or less.

I just ordered and received 25 4 pole, Double Throw locking type toggle switches from Digikey to be wired up for club members radios. These switches use silver contacts, with a maximum resistance specification of 0.01 Ohms. I checked one by calculation, it came up as 0.0032 Ohms. All 100 contacts of those 25 switches were checked with my Fluke 87V meter with its high resolution resistance range that can read to 0.01 Ohms. Every contact measured to zero ohms on that meter range. Those 100 contacts were checked "right out of the box" without moving any of the switch toggles.

The switch used is Digikeys 360-1871-ND. No, they are not cheap switches.
http://www.digikey.com/product-searc...ds=360-1871-nd

Some 15 years ago, I had an Astroflight geared 90 brush type motor, running on 38 Nicad cells. Interference with that system was so bad, I only got around 20 feet of range on my Futaba 72 Mhz radio system. With the antenna fully extended!

One inch diameter ferrite rings on the two motor supply wires cleaned up the Astro brush noise to where flights could be made with it. Those same ferrite rings on the connection to the receiver throttle channel had zero effect on the glitches.
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Old Mar 25, 2015, 01:16 PM
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I wouldn't worry about even using the ferrite ring. I never had an electric powered model when I was running 72MHz so I never really saw one until I saw them on a friends plane.

When I switched to 2.4GHz, I still never saw a ferrite ring until I got into some different kinds of ESC's. I just took 'em off since they were in the way and shortened the lead to the ESC too much. At first I carefully pulled the pins out of the connector so I could unwind the wire in case I found out I needed the ring, now I just use a pair of pliers to remove them as they're pretty easy to break.... lol
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Old Mar 25, 2015, 03:33 PM
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The rings are not there to sustain the power bus so much as to keep high frequency spikes away from the receiver. A square wave as generated by the ESC to power the motor is an ideal generator of high frequency spikes. Some ESC's do not have them because the makers of those ESC's do not care if their ESC causes problems with the receiver.

But you can do as you wish. I have said my say on this subject.
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Old Mar 25, 2015, 03:49 PM
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2.4 Ghz frequencies

Nice thing about those 2.4 Ghz receivers. It is not easy to generate Radio Frequency interference at these 2.4 Ghz frequencies. At 2.4 Ghz, a piece of wire a couple of inches long can be a near open circuit. (Or a dead short, depending on whether that wire is "Tuned" to 2.4 Ghz)

The MosFets we use likely have maximum frequency limits around 20 Mhz or so. That is 100 times lower in frequency than our 2.4 Ghz receivers. But if you're using 72 Mhz radios, IMHO, it would not be a very good idea to remove those ferrite rings.
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Old Mar 25, 2015, 06:48 PM
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The RF section of the receiver is not the only part that is susceptible to glitchs. But do what you want with your stuff. I am leaving the cores on.
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