Recommended Ferrite Ring for SO3 Routers

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Recommended Ferrite Ring for SO3 Routers

Post by woodworkerbob » Wed Jul 22, 2015 2:27 pm

I've had the problem of the control board disconnecting from the computer when I turn off the Dewalt router. Got a way too expensive power strip that is supposed to reduce surges. I think the power strip helped, but I still have the problem every now and then.

I'm willing to drop some coin on some ferrite rings, but have no idea where to begin. Amazon has a bunch but I'm pretty clueless.

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None, that's a hardware problem.

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Re: Recommended Ferrite Ring for SO3 Routers

Post by swhillier » Fri Jul 24, 2015 1:40 am

I just picked up a couple based on the inside diameter so they would fit the power cable. I think it was 7mm which is pretty snug but fit. Even after I put the ferrite beads on, using separate power circuits and routing wires to opposite sides I was still getting occasional dropped connections when using the switch on the router. I then started using the switch on my power bar. Since I stopped using the switch on the router I haven't had a problem.

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Re: Recommended Ferrite Ring for SO3 Routers

Post by veng1 » Fri Jul 24, 2015 3:15 pm

Because ferrite rings are inductive devices, they are opposing the flow of current and, obviously, far more current flows through the router than the signal wires. So it might work better to use several small rings (actually, they are usually called toroids) on the limit switch, USB and related wires. But there is nothing wrong with using them on the power.

Because the current spikes are generated in the router, the toroid should be located as close to the router power input as possible.

Inductance varies with the square of the number of turns, so threading the router wire multiple times in the same direction through the toroid will dramatically increase the impedance to the flow of the noise. These turns need to be through the center, around the outer edge and back through the center. They can't be a simple zig-zag stuck through the center. And, yes, I know that it probably will require cutting the plug off the end to get the multiple turns.

Another option is a speed control that uses zero switching. If you turn the router off when the input AC waveform is at zero volts then the energy spike is very small. Similarly, if you turn the speed down before turning it off, the current and attendant noise spike is less.

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Re: Recommended Ferrite Ring for SO3 Routers

Post by jfdotcom » Sat Jul 25, 2015 2:53 pm

Have you tried putting the router on a different circuit than the control board? It was a quick fix for me although I'm still going to get ferrite rings for everything (Amazon has tons for a few bucks each)
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Re: Recommended Ferrite Ring for SO3 Routers

Post by OttoPilot » Sun Aug 23, 2015 1:00 am

Having the same issue. It appears to lose connection about 1/3 of the time when I power down the router.

Router is on another circuit - didn't help.
Ordered a new USB cable with ferrite beads at either end - didn't help.
Ordered 15x 7mm ferrite beads for the router power cord - didn't help.
Added remaining ferrite beads to all other wires - didn't help

Really frustrating when you're running a job with multiple tool changes and it drops out right before the last tool change...

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Re: Recommended Ferrite Ring for SO3 Routers

Post by LTEPM » Sun Aug 23, 2015 2:54 am

I installed ferrite cores around the router power cable by the strain relief. Installed a ferrite core on the +24 VDC cable in the power supply after the molex connector in the case and ensure the cable is not dressed in so it is near the 120VAC line connector. Installed a 'RF filter' around the X&Z wires before they entered the carbide motion board area. To me the RF filter looks like a large snap on ferrite core.

Routed the router power line along the dust collection hose from the dust boot to the right front corner of the SO3. Purchased a USB cable with ferrite cores on both ends. Use cable mounts and cable tie USB cable to ensure it doesn't mone during operation and break contact.

I turn on the router with the power strip switch. I don't touch the router while it is running. The Shop Vacuum is also isolated to another electrical panel.

This has minimized the disconnect issues I was experiencing. Debating whether or not to install bonding straps from the router mount, Z plates, rails, and end plates to minimize difference of potential. I would need to drill and tap the router mount and remove paint from the plates. The rails could be bonded from the screws on the plates., no holes should be required in the rails.

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Re: Recommended Ferrite Ring for SO3 Routers

Post by wunderaa » Thu Aug 27, 2015 6:37 pm

No picture with me, but I ordered the ferrite ring below and wrapped the router power cable through it like 4 times. I cannot get the board to drop out now at all. Just one data point, but it appears to have worked for me. ... ge_o02_s00

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Re: Recommended Ferrite Ring for SO3 Routers

Post by wunderaa » Fri Aug 28, 2015 2:20 am

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Re: Recommended Ferrite Ring for SO3 Routers

Post by zerblatt007 » Fri Aug 28, 2015 10:19 am

I am no expert at this, but ferrite cores seems to have two different uses depending on if you want to shield your cable from outside noise or want to suppress spikes on a AC or DC cable to reach some destination.
On the USB cables you place a core on each end to make the shielding "better".
To suppress spikes on cables without shielding like AC og DC powercables, one turn or perhaps more through seems to help. (on commercial equipment I have seen they settle for one turn)

On my SO doing both seems to have helped in addition to grounding the vacuum hose with bare copper wire wrapped around it..
I found a lot of cores on old VGA cables. They can not be opened and you have to destroy the cable, but for 5V and 24V there was just enough space for one turn.
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Re: Recommended Ferrite Ring for SO3 Routers

Post by CCSnell » Sun Sep 20, 2015 6:00 am

I had the same problems that many are experiencing with the USB disconnecting when the router is switched on. I saw the problem as one that probably needed more than just one level of interference protection. I started with ferrite cores on every cable, added a noise isolation surge protector ... ULTRABLOK/ and finished it off with a shielded power cable (CF6-07-03) ... ?c=US&l=en to the router (IGUS sells by the foot). The major difference was seen after adding the shielded power cable. No more disconnects AT ALL, even on a 10 ft USB cable.
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