RF through an intense e-mag field?

We have tested some simple digital RF transitters. They where installed inside a 500A motor connection box and they all worked OK.

We where expecting big problems but none have surfaced.

Is this normal?

Have any done such thing?

I've never tried such a thing... but isn't the magnetic field in a motor mostly concentrated in the small gap between the stator and the rotor (and, of course, within the iron core parts)? Also, 50 or 60 Hz frequency would probably not affect RF communications that much.

I would be more cautious about using RF comms in close proximity of VFDs and servos - anything that switches rapidly.

Other factors would also include:

Power of transmitter
Frequency range
Antenna
Above to include ERP (Effective radiated power)
Distance
Type of digital communication
Signal path to reciever

With enough power / erp, generally there is no problem

But, lack of line of sight on higher frequencies, operating over sand (dessert, strange grounding problems), operating over mines (again, ground) etc can have great affects, like transmitting through concrete or metal walls, etc.

regards.....kc

Thanks guys!

We where transmnitting a dry contact state (high temps switch) from inside the motor box to 300 feet away with a Car remote starter type of transmitter.

To our surprise it worked perfectly.

I am really impressed!

regards.....kc