Industrial Application Analog Camera On Brass Slip Ring Contacs.

I have a industrial client with a machine that spins 1500 rpm the camera is mounted on the machine (there is no other option). We have the camera installed directly onto the metal of the machine (it could be isolated) and connection is thru carbon brushes and 4 brass slip rings. Picture is great until we get up to speed then noise on picture makes it almost useless and very annoying for the operator to monitor the process. Camera is 12vdc, would a 24vac camera work better? Is there a noise filter for this type of application? We sanded slip rings with the machine running and seated the brushes in place with sand paper as well. Is there a conductive grease that can be used to increase conductivity on the slip ring? I'm thinking noise is coming off machine. We used rg59 and made every effort to to keep wiring away from the 480 3 phase motor wiring.


Any chance you can change the camera from analog to digital?

Like maybe an SDI camera? They use the same cable, but an SDI camera will be more resistant to noise the of the brushes, since it's digitally encoded before transmission.

the easy things to try are:

1. if you hold the camera in your hand, in the same relevant spot, OSHA, maybe wrap it on foam and tape it there. Does the same results occur? If it improves greatly, then try.

Speco VIDGL coax ground loop isolator.

Use a Coax to twisted PAIR set of baluns.


Send 12 Volts to the camera across a twisted pair video/power balun using
use shielded CAT5e, terminate the shield at the power source end. SAME as recorder.

Why would the ground loop occur only when the machine is spinning?

UD1 - Is that a quiz? :) inductance is the key to your question.
nothing from the video source end need be touching or connected to machine ground.
loops can be everywhere - and for many reasons - the right tool to confirm is an oscilloscope.

Industrial grounding

Agree, inductance from the motor, is the natural suspect for the noise.

Like a running a hair dryer next to an AM radio.

Would you consider that noise the result of a ground loop?

Not a quiz, just curious and always learning. :)

that probably falls under emf, and the radio is not acting as a connection between two devices. The coax, the power, via the camera may be... a poor ground on the coax, or the machine ground floating (some do).

the good ole' O'scope from machine earth to coax - shield would show some noise....

Thanks for the ideas. No oscilloscope available if it's ground loop.It is like none I have seen.. It appears to be most prominent in one part of the revolution. Looks like it's going to be an experiment in creativity.and ezperimentation.
Thanks for the ideas. No oscilloscope available if it's ground loop.It is like none I have seen.. It appears to be most prominent in one part of the revolution. Looks like it's going to be an experiment in creativity.and ezperimentation.

I didn't ask about the source and length of the 12v run?
DC wires are commonly non-twisted, thus no CCMR.
just a braindump previously, and add use a 12v battery for camera power, that will be clean,
be ready to add the ground loop isolators.
have the video / power baluns in the tool kit too.

Hopefully being lucky is better than being good.

Have you considered a cheap IP camera with wifi?

If that won't work for some reason, I'd consider baluns as the next option.

Keith, is the camera module you are using an esoteric or bespoke module? Is it severely size constrained?

In addition to SDI, a wifi camera might work also. Not sure, going to see if my GoPro works on a drill... ;)

Also, if there is room, put a signal booster on the cameras output, and then reduce after.

<edit: beaten to the punch again by Karas>