Digital Ballast EMI

[OG BURNT UP]

I read that you can put ferrite core on the ballast cord going to wall. Place one every 5 foot. Make sure you get the right size. It has to fit tight.

Also the new Blue Lab EC/ph monitor suppose to come with a shielded cable now. The old one was white and now it's grey.

 

[whazzup]

EMI is a double ended sword... when you make equipment that generates EMI you should be within the limits of what is required by FCC (and still you have the class A (industrial) and B (residential)), but if you produce equipment that is sensitive to EMI you should make sure that EMI which is within the FCC limits will not cause any interference. EMI experienced is not always the fault of the equipment generating EMI.

Nevertheless: one thing I can assure you: Any remote high frequency ballast (including ours) with a cord longer than a few ft will cause EMI beyond normal acceptable levels. Shielded cables is not a solution: for example it causes big problems for ignition, as it interferes with the ignition pulse.

A few guidelines to keep the EMI as low as possible:

- Keep lamp cords SHORT - ballast close to the lamp
- Never coil lamp cords, make them shorter to size
- Never have your lamp cords run close or parallel to your mains cords, as this can cause polluted mains and can even destroy your ballasts by feedback (all machines are amplifiers)

Best solution: buy integrated fixtures where there is no unshielded lamp cord. There are millions of fixtures hanging in our greenhouses, but none is remote. Would we use remote electronic ballasts we would have the biggest broadcast station in the world

Be advised that it is normally the harmonics that cause the EMI. Modern electronic ballasts can go up to 140 kHz, specifically when dimmed. Harmonics are a much higher frequency.

 

[redclayguerilla]

I think I will stick with magnetic ballasts.

 

[whazzup]

That is always an option. For optimal output though and no EMI, low power use, less heat development, better light maintenance and no sensitivity to mains voltage drops I would recommend a 1000W full fixture with the Philips double ended lamp.

Do the calculation and see how long it will take you to break even, based on the extra yield. That's within your first crop cycle.