Upgrading to 3 HP air cooled spindle

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey William,

if your display connected to the Onefinity Controller goes black, it is probable that EMI is the cause. Because the current that a VFD produces is by no means nice sine waves, VFDs and the spindle cables are a heavy source of EMI. Therefore the VFD must be enclosed into a grounded VFD control cabinet, the spindle motor cable must be shielded and properly terminated, and the machine must be correctly bonded and grounded.

If you ensured all this, you can finally try to add clip-on ferrite cores to your HDMI display cable.

@Aiph5u

Dealing with electromagnetic interference (EMI)

A first countermeasure against EMI would be to add ferrite cores. Remember EMI is something that acts on a cable, but a cable can also emit it.

However you can also try to avoid the sources of EMI:

Heavy sources of EMI are

1. A VFD that is not enclosed in a grounded VFD Control Cabinet

2. A spindle power cable that is not properly shielded and terminated (for this, see also this important document (PDF))

3. The carbon-brush commutators of a hand trim router, which is a Universal Motor (also called commutated series-wound motor) (see also router / spindle comparison ). As you can’t prevent the sparks of a router’s commutator, think of replacing the stepper cables by shielded cables (Make your own stepper cables for Buildbotics and Onefinity)

The best way to prevent EMI

To not only prevent EMI but also to comply EN/IEC 60204-1 safety standard, the machine should be electrically bonded and grounded. Here the links with the relevant information on how to do this:

• Static electricity in a router
• Proper Grounding; How have you grounded your frame?
• Material and Tools needed to ground your Onefinity CNC

Welcome to the forum!