- #1
quikpik
- 2
- 0
Two questions here. From real-world problems, I was hoping someone smarter than me could explain the physics behind some issues I was told about. It's been a long time since I looked at an engineering or physics book, so please bear with me.
1) For a 3-phase motor, I was told that someone had the idea to run each conductor in its own conduit. He thought it was a good idea until the wires started to heat up and melt. Let's assume that the wires were sized for the correct full load amps of the motor. I was told that when the 3 conductors are run in the same conduit, that voltage/current offset each other. When they were run independently, it must've induced some sort of a charge in the conduit causing it to heat up? Is this possible, or is this story made up?
2) If I have a power supply, very high DC voltage (~60kV) with very low current (15mA), do you have to keep the wiring away from all metal? This is more of an engineering installation question, so maybe this isn't appropriate here. I was of the belief that as long as things were non-ferrous, everything would be fine, perhaps even putting the cables in aluminum conduit. I was told this was bad practice. For such an installation, no metal (even non-ferrous) should be within a foot of the cable, due to the possibility of the cable inducing a charge on nearby ungrounded metal. If someone were to then touch that metal, they're liable to get a shock. Is this backed by science?
Thanks for any explanations. It's been a long time since I even had to think about Maxwell or Faraday.
1) For a 3-phase motor, I was told that someone had the idea to run each conductor in its own conduit. He thought it was a good idea until the wires started to heat up and melt. Let's assume that the wires were sized for the correct full load amps of the motor. I was told that when the 3 conductors are run in the same conduit, that voltage/current offset each other. When they were run independently, it must've induced some sort of a charge in the conduit causing it to heat up? Is this possible, or is this story made up?
2) If I have a power supply, very high DC voltage (~60kV) with very low current (15mA), do you have to keep the wiring away from all metal? This is more of an engineering installation question, so maybe this isn't appropriate here. I was of the belief that as long as things were non-ferrous, everything would be fine, perhaps even putting the cables in aluminum conduit. I was told this was bad practice. For such an installation, no metal (even non-ferrous) should be within a foot of the cable, due to the possibility of the cable inducing a charge on nearby ungrounded metal. If someone were to then touch that metal, they're liable to get a shock. Is this backed by science?
Thanks for any explanations. It's been a long time since I even had to think about Maxwell or Faraday.