VFDs are troublesome devices (at least the ones most buy, not the nice FCC and UL certified ones of course). Spacing cables away is first. Parallel cables are a bad idea. Properly shielded and earthed VFD and spindle. Ferrites are a band aid, fix the source, don't try to band aid and prevent every symptom of the bad source of radiating EMI
Ok peter I understood, this is what I planned. Apart from using the ferrites I have to provide an individual Earth Ground for the whole cable circuit of the machine or can I connect to the domestic Earth circuit?
Mains ground (known as EARTH in my part of the world) usually suffices. Wall plug's Earth > PE Screw on VFD > Earth wire and shield of cable between VFD and Spindle connects to PE screw. At the spindle the shield is NOT connected, but the Earth wire is, to the spindle body. But your VFD manual might (should) give appropriate guidance. Also see the VFD section of our EMI writeup: docs:blackbox-x32:faq-emi [OpenBuilds Documentation]
Hello everyone, Here the fight against the EMI does not progress, the machine works wonderfully with the PC (wifi connection), when I connect the Interface to BlackBox and I start the system all the functions are Ok, but Interface and CNC becomes completely crazy as soon as I start the Spindle! Since my last intervention on December 22 I have made the following modifications on the wiring: VFD is in Earth Deported the Spindle cable out of the chain and in Earth, the cable is now suspended above the machine Connected Spindle's body to Earth via the Gantry. Gantry is also in Earth. Connected the 0-10V cable shield from Blackbox to Earth. Received this morning and installed the ferrites on all the cables: Blackbox input and interface Input and output of the VFD cables The CNC is not in a very easy place and at my feeling The VFD box is still too close to the machine and electronics (50 cm.), I could place the VFD box in a place where I would need 2.5 meters For the Spindle cable and 3.5 meters for the 0-10V cable. I have no choice if I want a distance between the CNC and the VFD box. Questions: Is it possible to have long lengths with the 0-10V cables and the Spindle cable? What maximum length for the 0-10V control cable between the VFD and Blackbox? What maximum length for power cable between the VFD and Spindle? What minimum distance between the VFD case and the electronics control (BlackBox-Interface)? What minimum distance between the Spindle cable and the 0-10V command cable? That's all I can say for the moment because I have no skills on HF solutions. If you wish I can also post photos on the work done. Thanks for reading me!
Crazy suggestion, but as the fight to fix the VFDs EMI seems insurmountable (for now) would you consider the easy way out? RoutER11 CNC Kit Is it possible to have long lengths with the 0-10V cables and the Spindle cable? - Yes, but shorter is better What maximum length for the 0-10V control cable between the VFD and Blackbox? - shortest you can manage What maximum length for power cable between the VFD and Spindle? - no real maximum, longer but routed clean away from low voltage wiring, is better than keeping it short but doing bad routing close to low voltage wiring What minimum distance between the VFD case and the electronics control (BlackBox-Interface)? - further is better - but conductive paths eats into distance - radiating interference out of the VFD back into the house wiring for example... What minimum distance between the Spindle cable and the 0-10V command cable? - minimum = as far away as possible I know these are vague, but VFDs are somewhat terrible (note we still don't bother selling them - rather we reinvented routers to have ER11 collets lol) - there is no magical right number for these questions On rereading that one might be bad. Frame picks up noise from spindle body that should have gone down to central earth point via an earth wire instead
Don't overlook the possibility of interference travelling through the mains wiring. Especially if the VFD is plugged into the same power strip as everything else, it might be worth trying a separate supply or an RFI filtering power socket.
Thank you Peter for these details, depending on what you say I will try the solution to deport the VFD box and change the 0-10V cable for a longer (also with shield, like the previous one). I will also remove the Earth link between the Gantry and the Spindle body and deport the Earth to put the central point inside the VFD box. As you say, the possibility of changing router is also a good idea that I considered, I have a Makita RT0700C router and also a Bosch Pro GKF600 router that I can also install. The first problem is that these machines are very noisy, and second problem, I would lose the management possibilities available with the Blackbox X32. I do not envisage this idea at the moment.
Thank you Misterg, According to the @Peter Van Der Walt recommendations, I will deport in another place the case which contains the VFD. This topology will allow the VFD to be plugged into another outlet in my workshop. Thank you for this track. I'll keep you informed of the results.
Hi misterg What components should the filter be installed? Psu > Blackbox? VFD? All? The PSU Openbuilds has an integrated filter already I presume? The Socket Wall Power Cable > VFD must be with shield? I suppose that the filter must be between the home sockets and the component to protect PSU / VFD!?
Yes it does The thing you want to do is stop the nasty 400hz VFD speweing EMI back into mains wiring (so filter on its power feed), Or get a Danfoss or Hitachi VFD (; pricey but much better than far east
Yes, what Peter said - in the supply to the VFD (to protect the rest of the world against interference generated by the VFD).
Ok, next step ... never ending shopping continues. - 1x power bar with HF protective filter and integrated overvoltage protection. - 2x HF 220 V 500UH filter - 1x 230 V / AC rotary switch Thanks for helping (Certified material with professional standards, purchased in professional stores in Switzerland)
Hi Peter, Considering your suggestion about the CNC RoutER11 kit. How to automate the start and stop of spindle as well as control of the rotation speed? In the event that I want to use another machine to do other types of work and also supply with spare parts (brushes), be able to consult the user manual before purchasing because I did not find any relevant information on this subject on the Internet. Thank you for your information and your help!
Docs docs:blackbox-x32:connect-dewalt-iotrelay [OpenBuilds Documentation] If you are constantly changing RPM you are doing CAM wrong (; Mines glued on 4-5 and only gets tweaked live if i hear chatter or bogging. Speeds "and feeds" keep speed constant. CAM up with different feeds
Thank you very much Alex but I see that this relay cannot be supplied with an AC 220V power See here if I make a mistake: https://www.digital-loggers.com/iot2Spec.pdf
You are correct - I also live in a 220/240 volt area and I've never found a reasonably priced alternative. Alex.
FWIW, I would take the earth from the VFD directly back to the tag on the EMI filter, where the earth from the supply is also connected. If you are putting the VFD in a metal enclosure, then I would mount the EMI filter in electrical contact with that enclosure and connect the screen from the spindle wiring to the enclosure (only) at the point that the wiring leaves the enclosure (otherwise, take the screen back to the tag on the EMI filter, also). Others may have different recommendations.
If you check out the VFD section of our EMI FAQ, we have a link to a brilliant external site Use of actual EMI filters are rare (not seen many folks have to go that far yet, makes me think something more basic is still wrong like shielding or earthing) I also second the two earth's are bad. Star from a single point. No daisy chain.
Hi, @Peter Van Der Walt @Misterg Thank you for your recommendations I went to see the information on https://www.motionControltips.com/Problems-vfds-CAUSE-COPLEPES-HELP-SOLVE/ I also found a link that relates everything you have already informed me in our discussion EMI Filter Installation Best Practices | EMI Filter Installation. Modified wiring scheme and will delete the old and put the new one so as not to leave bad information in the thread, give me your opinion that will allow me to know if I understood you well). I received and installed the power bar but it doesn't change the problem. Tomorrow I would receive the filters (I had to order 3 to be delivered, but no problem I will keep them in reserve ... it does not eat caviar *********************************************************************** I must mention an important thing about my 0-10V VFD> bbx32 control cable; This is a cable that I use for video surveillance and access control, is double shielded (4x 0.8 U72 HF mm. Rigid), it is 1.70 meters long (5.6ft). When I put my VFD under tension the Spindle runs at 1600 RPM without instruction in the control software for startup. This has occurred since I deported the VFD in the box which is now on the opposite side of the X32 and the CNC, which I had to increase the length of the 0-10V control cable which connects the VFD at the X32. Previously for reasons of practicality and cabling comfort The X32 and the VFD were located on the same side of the CNC, the control cable measured 60 cm. (2.0ft) In this configuration I had never had a problem. *********************************************************************** My case is a reference in terms of debug or have you had similar situations before? In advance 2 pics to see the situation
Forgot to setup the MIN FREQ parameter on VFD (only allow 7200 rpm plus for spindle's safety - does double duty as an OFF function) 3 phase cable's shield should be pigtailed to star ground point
Duplicate post? Replied to questions above the repost Also, if that VFD doesnt have a min freq option, you might have to use VFD A2-8015 to BB x32
Yes I have to see the RPM Min & Max again so that the Spindle does not start below 3000 RPM (I must be too low with my minimum setting, with the old cable of 2 Ft that had never happened, I do not has no response to this anomaly.
Certainly, tomorrow I have to dismantle the box and completely redo the wiring with the new filter and put the cables and shields in star on the plate
