Wire sizes help please.....
- Thread starter Bartman
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skivvie
Member
another:
http://circuitwizard.bluesea.com/
http://circuitwizard.bluesea.com/
Bartman
Welcome to MultiRotorForums.com!!
thanks for the quick replies.
if the circuit is horseshoe shaped and being supplied at each side with battery inputs, would the conductor size be halved? or reduced by some factor due to the two conductors? if the battery connector were placed in the middle then only the leads to the horseshoe would be full size and the rest would be half, no?
thanks,
bart
if the circuit is horseshoe shaped and being supplied at each side with battery inputs, would the conductor size be halved? or reduced by some factor due to the two conductors? if the battery connector were placed in the middle then only the leads to the horseshoe would be full size and the rest would be half, no?
thanks,
bart
Bartman
Welcome to MultiRotorForums.com!!
Hi Jes, I'm trying to size wire for an open loop power distribution harness. I'm assuming 25 amps per motor, 8 motors, 4 cell lipo power. if the power comes in from the middle then it's only half the load on each branch, right? I've used 10AWG wire for this but the sizing calculators make it look more like 6 would be necessary.
redridinghood
Member
I remember reading a Castle esc comment from an engineer about how the power is transmitted on the wire surface. More strands are better.
Bartman
Welcome to MultiRotorForums.com!!
wikipedia to the rescue
[h=2][/h] Solid wire, also called solid-core or single-strand wire, consists of one piece of metal wire. Stranded wire is composed of a bundle wires to make a larger conductor.
Stranded wire is more flexible than solid wire of the same total cross-sectional area. Solid wire is cheaper to manufacture than stranded wire and is used where there is little need for flexibility in the wire. Solid wire also provides mechanical ruggedness; and, because it has relatively less surface area which is exposed to attack by corrosives, protection against the environment. Stranded wire is used when higher resistance to metal fatigue is required. Such situations include connections between circuit boards in multi-printed-circuit-board devices, where the rigidity of solid wire would produce too much stress as a result of movement during assembly or servicing; A.C. line cords for appliances; musical instrument cables; computer mouse cables; welding electrode cables; control cables connecting moving machine parts; mining machine cables; trailing machine cables; and numerous others.
At high frequencies, current travels near the surface of the wire because of the skin effect, resulting in increased power loss in the wire. Stranded wire might seem to reduce this effect, since the total surface area of the strands is greater than the surface area of the equivalent solid wire, but ordinary stranded wire does not reduce the skin effect because all the strands are short-circuited together and behave as a single conductor. A stranded wire will have higher resistance than a solid wire of the same diameter because the cross-section of the stranded wire is not all copper; there are unavoidable gaps between the strands (this is the circle packing problem for circles within a circle). A stranded wire with the same cross-section of conductor as a solid wire is said to have the same equivalent gauge and is always a larger diameter.
However, for many high-frequency applications, proximity effect is more severe than skin effect, and in some limited cases, simple stranded wire can reduce proximity effect. For better performance at high frequencies, litz wire, which has the individual strands insulated and twisted in special patterns, may be used.
[h=2][/h] Solid wire, also called solid-core or single-strand wire, consists of one piece of metal wire. Stranded wire is composed of a bundle wires to make a larger conductor.
Stranded wire is more flexible than solid wire of the same total cross-sectional area. Solid wire is cheaper to manufacture than stranded wire and is used where there is little need for flexibility in the wire. Solid wire also provides mechanical ruggedness; and, because it has relatively less surface area which is exposed to attack by corrosives, protection against the environment. Stranded wire is used when higher resistance to metal fatigue is required. Such situations include connections between circuit boards in multi-printed-circuit-board devices, where the rigidity of solid wire would produce too much stress as a result of movement during assembly or servicing; A.C. line cords for appliances; musical instrument cables; computer mouse cables; welding electrode cables; control cables connecting moving machine parts; mining machine cables; trailing machine cables; and numerous others.
At high frequencies, current travels near the surface of the wire because of the skin effect, resulting in increased power loss in the wire. Stranded wire might seem to reduce this effect, since the total surface area of the strands is greater than the surface area of the equivalent solid wire, but ordinary stranded wire does not reduce the skin effect because all the strands are short-circuited together and behave as a single conductor. A stranded wire will have higher resistance than a solid wire of the same diameter because the cross-section of the stranded wire is not all copper; there are unavoidable gaps between the strands (this is the circle packing problem for circles within a circle). A stranded wire with the same cross-section of conductor as a solid wire is said to have the same equivalent gauge and is always a larger diameter.
However, for many high-frequency applications, proximity effect is more severe than skin effect, and in some limited cases, simple stranded wire can reduce proximity effect. For better performance at high frequencies, litz wire, which has the individual strands insulated and twisted in special patterns, may be used.
Bartman
Welcome to MultiRotorForums.com!!
the wikipedia article debunks that. if it's accurate then I'm fine with that as 10 AWG solid will work for what I'm trying to do. if I'm successful we'll have an entirely new method for power distribution available.
Be careful with solid wire: movement and vibration will stress the joints and it will fracture remarkably easily. It belongs in the walls of your house, not really on a multirotor ;-)
The common choie for RC apps is multistrand with silicone covering: multistrand for the flexibility (and therefore resistance to internal fracture) and silicone for its heat resistance ('cos we exceed the "normal" ratings).
The common choie for RC apps is multistrand with silicone covering: multistrand for the flexibility (and therefore resistance to internal fracture) and silicone for its heat resistance ('cos we exceed the "normal" ratings).
I'm very interested to see what your results are and also thought that was a very net resting Wikipedia article excerpt regarding the comparison between stranded and solid wire gauges. The reason for my interest in this is that for my new SkyJib 8 (long term work in progress) that will use 8 x CC 75A ESCs (in the event that someone can't suggest a tried method that is better, as I already made the Aerodrive 8 mistake...I went to the hardware store yesterday and, again in lieu of a better idea, was gonna use the solid conductor to shape it into an octagon, one each for +/-, then insulate each from the other and tap each ESC into the pair of shape sections nearest to them. Do you think this will work well??
Thanks very much, in advance, for your input here; greatly appreciated!
-Jonathan