Noise due to chattering of relay

In summary: So, to couple the noise, you can connect small antennas to each side of the spark gap or wrap the wire around the relay casing. This will help to reduce the interference. In summary, to couple noise due to chattering of relay, you can connect short antennas to each side of the spark gap or wrap the wire around the relay casing to reduce interference.
  • #1
Nikhil N
81
2
I need to know how to couple noise due to chattering of relay? I have seen the below method to couple. But I want more detailed circuit to do this. Please help me. Also I want to know where the tremendous amount of EMI can be seen ? Is it across the coil of relay?
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  • #2
Nikhil N said:
I need to know how to couple noise due to chattering of relay? I have seen the below method to couple. But I want more detailed circuit to do this. Please help me. Also I want to know where the tremendous amount of EMI can be seen ? Is it across the coil of relay?View attachment 112626
I believe the radiation occurs because when the contact starts to open, the inductance of the coil creates a forward EMF and this then causes the gap to break down again. This breakdown is very fast, and you may know that one of the early radio experimenters, Bose, obtained results using a spark gap at 40 GHz. So we may assume it breaks down in picoseconds. Any energy that is stored in the capacitance of the wires will then be converted into oscillatory energy at all frequencies at which the wires have a resonance. To obtain "good" radiation, I suggest connecting short antennas to each side of the spark gap, to form a dipole, or opening out the wiring each side of the contact to form a loop. Remember that the pulse in the coil itself will be quite slow.
I have used a buzzer of this type, using a little relay, as a source of RF for an impedance bridge, as a wavemeter and for measuring resonant frequencies of tuned circuits etc.
 
  • #3
tech99 said:
I believe the radiation occurs because when the contact starts to open, the inductance of the coil creates a forward EMF and this then causes the gap to break down again. This breakdown is very fast, and you may know that one of the early radio experimenters, Bose, obtained results using a spark gap at 40 GHz. So we may assume it breaks down in picoseconds. Any energy that is stored in the capacitance of the wires will then be converted into oscillatory energy at all frequencies at which the wires have a resonance. To obtain "good" radiation, I suggest connecting short antennas to each side of the spark gap, to form a dipole, or opening out the wiring each side of the contact to form a loop. Remember that the pulse in the coil itself will be quite slow.
I have used a buzzer of this type, using a little relay, as a source of RF for an impedance bridge, as a wavemeter and for measuring resonant frequencies of tuned circuits etc.
Thanks for the replay. Now what's my doubt is U have suggested to connect small antennas to each of the spark gap, by this u have meant to connect the antennas to the coil ends ? Can I wound the wire to which I have to couple the noise onto the relay casing in order to couple the interference?
 
  • #4
Nikhil N said:
Thanks for the replay. Now what's my doubt is U have suggested to connect small antennas to each of the spark gap, by this u have meant to connect the antennas to the coil ends ? Can I wound the wire to which I have to couple the noise onto the relay casing in order to couple the interference?
The noise comes from the contact, not from the coil.
 

FAQ: Noise due to chattering of relay

1. What is noise due to chattering of relay?

Noise due to chattering of relay is a type of electrical interference that can occur when a relay rapidly switches on and off, causing a clicking or buzzing sound. This noise can disrupt electronic devices and can also indicate a malfunctioning relay.

2. What causes noise due to chattering of relay?

Noise due to chattering of relay is caused by the rapid opening and closing of the relay contacts, which creates an electromagnetic field that can interfere with other electronic components.

3. How can noise due to chattering of relay be prevented?

Noise due to chattering of relay can be prevented by using a relay with a higher contact rating, adding a snubber circuit to absorb excess voltage, or using a solid-state relay instead of an electromechanical one.

4. Can noise due to chattering of relay damage electronic devices?

While the noise itself may not damage electronic devices, it can indicate a larger issue with the relay that could potentially damage the devices. Therefore, it is important to address the cause of the noise to prevent any potential damage.

5. How can I troubleshoot noise due to chattering of relay?

To troubleshoot noise due to chattering of relay, you can check for loose connections, replace the relay with a higher rated one, or add a snubber circuit. If the noise persists, it may be a sign of a larger issue and a professional should be consulted.

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