3 ms·

I used to do some welding with a stick welder with 100 feet of 4/0 gauge copper welding cable. Super heavy to drag around and very difficult to wind up. And tha

I used to do some welding with a stick welder with 100 feet of 4/0 gauge copper welding cable. Super heavy to drag around and very difficult to wind up. And that was for a few kW. So these 2MW cables will need mechanical support. You can use parallel cables with fine strands or water cooled cables supported by a balanced or power assisted arm to assist in manipulating those cables. So that's not really a big deal. And 2MW isn't that ambitious considering much larger switched power systems exist like the 70MW 25 cycle static inverters for Amtrak's system in Sunnyside yards. See also large scale PV solar installs.

londons_explore 7y ago
A quick thought experiment... If you wanted to transfer 2MW, you could do it at 200 amps and 10,000 volts. Two 200 amp conductors, 3 meters long, and 10 mm^2 cross sectional area will come out at half a kilogram. 400 watts of heating will happen in the wire, which could be cooled by a 1mm^2 water/steam cooling pipe running at 1 ml/sec. That weighs another 6 grams. Insulating a 10,000 volt supply sounds a lot, but if the wire was insulated with PTFE, with a 10x safety margin, you would only need a thickness of 1mm on each conductor. Total weight 140 grams. So - the total weight of a 2 Megawatt human-safe cable could, with the right engineering, be under a kilogram for 3 meters of cable, plenty to hook up your car or truck.
- baybal2 7y ago
  10kw? You will either need top tier, liquid cooled IGBTs or magnetics — both are not an option on a car. Maximum what FETs your money can buy can handle is 1500V. It's not them being that heavy, it's them being very stiff.
  - MisterTea 7y ago
    IGCT's can handle a few kV and 1000's of amps. Plus you can setries them and increase the blocking voltage. Same goes for IGBT's, SCR's.
- MisterTea 7y ago
  Medium voltage charging isn't a big challenge considering some mining equipment is already powered by medium voltage. Those mammoth draglines and bucket excavators are powered by an actual high voltage extension cord that is moved around with the machine. They even have plugs and connectors, saw one rated for 25kV and 600A, three phase. That's almost 26MW. Totally doable.

londons_explore 7y ago

A quick thought experiment... If you wanted to transfer 2MW, you could do it at 200 amps and 10,000 volts. Two 200 amp conductors, 3 meters long, and 10 mm^2 cross sectional area will come out at half a kilogram. 400 watts of heating will happen in the wire, which could be cooled by a 1mm^2 water/steam cooling pipe running at 1 ml/sec. That weighs another 6 grams. Insulating a 10,000 volt supply sounds a lot, but if the wire was insulated with PTFE, with a 10x safety margin, you would only need a thickness of 1mm on each conductor. Total weight 140 grams. So - the total weight of a 2 Megawatt human-safe cable could, with the right engineering, be under a kilogram for 3 meters of cable, plenty to hook up your car or truck.

baybal2 7y ago
10kw? You will either need top tier, liquid cooled IGBTs or magnetics — both are not an option on a car. Maximum what FETs your money can buy can handle is 1500V. It's not them being that heavy, it's them being very stiff.
- MisterTea 7y ago
  IGCT's can handle a few kV and 1000's of amps. Plus you can setries them and increase the blocking voltage. Same goes for IGBT's, SCR's.
MisterTea 7y ago
Medium voltage charging isn't a big challenge considering some mining equipment is already powered by medium voltage. Those mammoth draglines and bucket excavators are powered by an actual high voltage extension cord that is moved around with the machine. They even have plugs and connectors, saw one rated for 25kV and 600A, three phase. That's almost 26MW. Totally doable.