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Sherlock_H
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3-pin (Gas Discharge Tube) Surge arrester rating "DC spark over voltage"
Could someone please help with a question about Gas Discharge tube, surge arresters rating?
I am looking at a public address audio equipment which uses a 100vrms audio lines driven from a audio transformer. Currently the equipment has a single two pin epcos surge arrester placed across audio line, (It's blue and marked 500). This has a 'DC spark-over' voltage of 500V and discharge class of 20KA/20A.
I have been asked to change this so its protects down to Earth rather than just across the line. Because of a lack of space I have chosen to use an equivalent 3pin type, with the centre pin being the Earth connection.
I have two problems that are confusing me,
1. I am not sure whether the 'DC spark-over' rating of 3pin arrester is still rated between the end pins down to the centre pin or still across the end pins. So, is a 250V 3pin type is equivalent to a 500V two pin type?
2. Assuming the voltage between each line to Earth will be half the voltage that's between the audio lines, do I choose an arrester that's also half the voltage across the audio lines, i.e 250V instead of 500V (depending on the answer to first question).
Thanks.
Could someone please help with a question about Gas Discharge tube, surge arresters rating?
I am looking at a public address audio equipment which uses a 100vrms audio lines driven from a audio transformer. Currently the equipment has a single two pin epcos surge arrester placed across audio line, (It's blue and marked 500). This has a 'DC spark-over' voltage of 500V and discharge class of 20KA/20A.
I have been asked to change this so its protects down to Earth rather than just across the line. Because of a lack of space I have chosen to use an equivalent 3pin type, with the centre pin being the Earth connection.
I have two problems that are confusing me,
1. I am not sure whether the 'DC spark-over' rating of 3pin arrester is still rated between the end pins down to the centre pin or still across the end pins. So, is a 250V 3pin type is equivalent to a 500V two pin type?
2. Assuming the voltage between each line to Earth will be half the voltage that's between the audio lines, do I choose an arrester that's also half the voltage across the audio lines, i.e 250V instead of 500V (depending on the answer to first question).
Thanks.
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