Re: Power cable conductor gage (AWG) of


Stone, Jack G
 

Migration of electrons have to exceed 740MHz to start migrating to the outer circumference of the conductor (depends on the conductor structure).  So your USB or interface cabling should account for signal attenuation or at least understand for the 15’ USB3 what is the specification!!!  Cannot go cheap on these – and ensure that they are well shielded, aluminum paper wrap is not shielding.

 

For the sake of our equipment – The mount will impart the largest di/dt.

Taking into account the data collected based on the loading (load and Fulcrum (lever) – you can ascertain at some maximum skew rate and the amount of current sinked  to mitigate violating the minimum voltage which can damage the instrument or throw off the accuracy.

 

That is the goal I would assume – taking into account the various loads from other devices; cameras, conversion factors, USB controllers and communication devices all have voltage limits.

If you exceed that minimum voltage in any of these devices you can expect inoperability. 

 

So understanding your power consumption and your input voltage vs. full load is the key goal I would suspect.

 

Minimalist path – use the thickest gauge with the highest strand count.  Source a silicon based insulator (varmints for some reason will not eat) and ensure that you contacts are sealed from moisture.  Sealed connects are important.  From your power distribution panel to the equipment. 

Purchase the best interface cables you can afford – after spending that $8K on that camera only to use dollar store USB – you would induce all that noise from the transition out of the camera to your storage device.  Does not make sense when you looking for that ultra low noise.

 

Cover unused connectors – at some point you might need them and if they are corroded it will impact the capability for the physical connection.  Some use RTV or clear silicon caulking.

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Seb@stro
Sent: Friday, April 09, 2021 1:12 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Power cable conductor gage (AWG) of

 

Christopher,

 

I leave half of that work to the UL/CSA compliance guys. 

 

And then, skin effect and velocity of propagation at 0Hz could be an interesting discussion... 😉

 

CS!

Sébastien

 


De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Christopher Erickson <christopher.k.erickson@...>
Envoyé : 9 avril 2021 15:47
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Power cable conductor gage (AWG) of

 

At least nobody started talking about skin effect, nominal velocity of propagation, current NEC electrical code requirements, insulation dielectric characteristics, breakdown voltages, mutual inductance, impedance, hysteresis, magnetic fields, reluctance, EMI shielding, plating techniques, ductility, annealing, connector MTBF, connector insertion lifetimes, NEMA ratings, EMP, lightning protection, R-56 compliance, insulation color coding, insulation UV ratings, US vs. ISO specifications, suppleness.......


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

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