| Electronics > Projects, Designs, and Technical Stuff |
| Massive EMI issues |
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| madires:
Maybe a monolithic or X2Y EMI filter for the DC motors? |
| OM222O:
--- Quote from: madires on June 01, 2020, 02:31:21 pm ---Maybe a monolithic or X2Y EMI filter for the DC motors? --- End quote --- Would that be helpful at the H bridge end? I'm guessing not but I'm not sure Also is that the same idea as applying 10nF caps between the grounded chassis and each terminal? |
| phil from seattle:
One of the problems with directly connecting to the encoders is those wires are antennas creating path for emi to enter the arduinos. You could try a low pass RC filter per input - resistor and cap, cheap. Pick a cutoff frequency that is, say, twice your max frequency. Even better would be to use opto isolators and completely isolate your arduinos. I agree with the ferrite suggestions above. Worth a try. You can never have too much EMI supression. Shielded wiring is worth investing in. Make sure it's a star grounded configuration. Eventually, you will need to get your power sorted out and filtered. |
| madires:
--- Quote from: OM222O on June 01, 2020, 03:46:33 pm ---Would that be helpful at the H bridge end? I'm guessing not but I'm not sure Also is that the same idea as applying 10nF caps between the grounded chassis and each terminal? --- End quote --- No, they should be placed at the EMI source, i.e. at the DC motor. The idea is similar but they comprise two Y caps and one X cap in one package, and provide better performance. |
| OM222O:
--- Quote from: madires on June 01, 2020, 04:55:27 pm --- --- Quote from: OM222O on June 01, 2020, 03:46:33 pm ---Would that be helpful at the H bridge end? I'm guessing not but I'm not sure Also is that the same idea as applying 10nF caps between the grounded chassis and each terminal? --- End quote --- No, they should be placed at the EMI source, i.e. at the DC motor. The idea is similar but they comprise two Y caps and one X cap in one package, and provide better performance. --- End quote --- As you can see from the motor pictures that's not really possible. I will have a go at using the aluminized mylar + ferrites to see if that'd help. Will try the capacitors to chassis as well. |
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