dominik h said:Measured with a temperature sensor attached to the phase wires.
I also tried to separate the wires from each other. But there was not much space.
dominik h said:Measured with a temperature sensor attached to the phase wires.
I also tried to separate the wires from each other. But there was not much space.
dominik h said:I think phase wires on my 5kW QS have an insulation rated for 180C. I tested the wires with a solder iron, above 250C they beginn to melt.
My new ones are rated 205C , melting starts here above 300C. The new wires are made in Germany.
There also exist 300C wires but the silicone-like insulation is very sensitive to cuts. These 205C wires have a very robust insulation.
I did the same "test" ride after getting rid of the protetive hose.
While normal use my wires stay below 130C.
dominik h said:. Phase wires are AWG4 16mm²
dominik h said:Sorry looked at a wrong conversion list, which says 16mm=awg4.
Phase wires are 16mm upgrade is 2x16 205C wires per phase.
Hope it is enough fü1r the Fardriver ND96850, and I have to Insert temperature Sensors n my Motors to present them from overheating wires and magnets.
dominik h said:Who can estmate with a picture.
Awg4 = 21,2mm
Awg5 = 16,8mm my new ones are multinorm wires so they have to be the same as AWG5
So the ones in my QS have to be smaller than your AWG4 .
neowizard said:SlowCo said:neowizard said:ebike11 said:Thanks for the advice..my main purpose is to use the 4awg as a heatsink when crimping the qs273 wires to it around 15cm outside of the hub. The 4awg will extend to around 80cm to the controller at the front of the bike. Im unable to put the controller any closer to the motor
I'm sorry, maybe I'm too new to all of this, but what do you mean when you say you want to use a cable as a heatsink?
Copper is not only a good electrical but also heat conducting material. So the heat in the motor can find it's way outside through the phase wires.
@ebike11:
I hope you're aware of "Statorade" to help cool a hub motor even better? Maybe even add "Hubsinks".
https://ebikes.ca/product-info/grin-products/statorade.html
I thought there was some terminology I was missing here. I didn't realize people are trying to use copper cables as some thermal vacuum.
Sure, copper's a great thermal conductor, but 3X4AWG amounts to less than 1cm2 of cross-section area. That's about the size of your pinky fingernail. Heat is supposed to flow up that narrow channel? If we were talking about a span of a millimeter, that might make sense, but over tens of cm? There's absolutely no way this will reduce even 0.1degC off the engine.
Say I hold a 50cm copper rod with a 1cm2 in cross-sectional area. I put one end in 95degC (the motor end) and the other end at 20degC. How much power will the rod "pull" across it? That's the temp diff multiplied by the cross-sectional area and the thermal conductivity of copper divided by length of the rod. Or 75degC * 1cm^2 * k_copper / 0.5m = 0.015*k_copper Watt. k_copper is ~400 W/mK. So that's 6W of power "pulled" across the rod. We can assume that the rod is mostly cold by 25cm, since it's open air, but we'll still get just 12W.
Even a rod of 5cm only gets us 60W, and at this point how do you even keep the cool end from heating up when it's drawing constant 60W (it's basically a soldering iron at this point).
No. Using cables to cool down a motor won't work.
ebike11 said:neowizard said:I thought there was some terminology I was missing here. I didn't realize people are trying to use copper cables as some thermal vacuum.
Sure, copper's a great thermal conductor, but 3X4AWG amounts to less than 1cm2 of cross-section area. That's about the size of your pinky fingernail. Heat is supposed to flow up that narrow channel? If we were talking about a span of a millimeter, that might make sense, but over tens of cm? There's absolutely no way this will reduce even 0.1degC off the engine.
Say I hold a 50cm copper rod with a 1cm2 in cross-sectional area. I put one end in 95degC (the motor end) and the other end at 20degC. How much power will the rod "pull" across it? That's the temp diff multiplied by the cross-sectional area and the thermal conductivity of copper divided by length of the rod. Or 75degC * 1cm^2 * k_copper / 0.5m = 0.015*k_copper Watt. k_copper is ~400 W/mK. So that's 6W of power "pulled" across the rod. We can assume that the rod is mostly cold by 25cm, since it's open air, but we'll still get just 12W.
Even a rod of 5cm only gets us 60W, and at this point how do you even keep the cool end from heating up when it's drawing constant 60W (it's basically a soldering iron at this point).
No. Using cables to cool down a motor won't work.
https://endless-sphere.com/forums/viewtopic.php?t=30127
neowizard said:From a brief reading, it looks like they're talking about reducing wire-losses and wire heat by going higher gauge. That's totally a thing, but won't cool your motor unless you replace the wires inside the motor. Bumping up the wire-size outside the motor will not cool the motor at all.
neowizard said:ebike11 said:neowizard said:I thought there was some terminology I was missing here. I didn't realize people are trying to use copper cables as some thermal vacuum.
Sure, copper's a great thermal conductor, but 3X4AWG amounts to less than 1cm2 of cross-section area. That's about the size of your pinky fingernail. Heat is supposed to flow up that narrow channel? If we were talking about a span of a millimeter, that might make sense, but over tens of cm? There's absolutely no way this will reduce even 0.1degC off the engine.
Say I hold a 50cm copper rod with a 1cm2 in cross-sectional area. I put one end in 95degC (the motor end) and the other end at 20degC. How much power will the rod "pull" across it? That's the temp diff multiplied by the cross-sectional area and the thermal conductivity of copper divided by length of the rod. Or 75degC * 1cm^2 * k_copper / 0.5m = 0.015*k_copper Watt. k_copper is ~400 W/mK. So that's 6W of power "pulled" across the rod. We can assume that the rod is mostly cold by 25cm, since it's open air, but we'll still get just 12W.
Even a rod of 5cm only gets us 60W, and at this point how do you even keep the cool end from heating up when it's drawing constant 60W (it's basically a soldering iron at this point).
No. Using cables to cool down a motor won't work.
https://endless-sphere.com/forums/viewtopic.php?t=30127
Sorry, I'm not sure what you're suggesting with this post-link.
From a brief reading, it looks like they're talking about reducing wire-losses and wire heat by going higher gauge. That's totally a thing, but won't cool your motor unless you replace the wires inside the motor. Bumping up the wire-size outside the motor will not cool the motor at all.
There were some suggestions there that say you can sink heat with thick wires. They're just wrong, and provide no data or basis to support that, though.
ebike11 said:neowizard said:Sorry, I'm not sure what you're suggesting with this post-link.
From a brief reading, it looks like they're talking about reducing wire-losses and wire heat by going higher gauge. That's totally a thing, but won't cool your motor unless you replace the wires inside the motor. Bumping up the wire-size outside the motor will not cool the motor at all.
There were some suggestions there that say you can sink heat with thick wires. They're just wrong, and provide no data or basis to support that, though.
But at least there is a benefit..even if its outside the motor. Id rather have a meter of 4awg than 12awg
neowizard said:ebike11 said:neowizard said:Sorry, I'm not sure what you're suggesting with this post-link.
From a brief reading, it looks like they're talking about reducing wire-losses and wire heat by going higher gauge. That's totally a thing, but won't cool your motor unless you replace the wires inside the motor. Bumping up the wire-size outside the motor will not cool the motor at all.
There were some suggestions there that say you can sink heat with thick wires. They're just wrong, and provide no data or basis to support that, though.
But at least there is a benefit..even if its outside the motor. Id rather have a meter of 4awg than 12awg
Yes, that's fair. I'd focus my efforts and money elsewhere, TBH, but to each their own.
I mainly posted here to quell that belief that you can sink heat through a 1cm^2 cross section of copper - which you can't in any meaningful quantity.
ebike11 said:I just wanna do as much as possible since the motor will see 30kw from time to time in bursts
Chalo said:ebike11 said:I just wanna do as much as possible since the motor will see 30kw from time to time in bursts
Accept the consequences and learn from them, faraway friend.
calab said:
ebike11 said:calab said:
Oh...never seen posters on here put their location name when referring to them
calab said:True, at best you could hope for a country then a state then a city then gps coordinates.
ebike11 said:calab said:
Oh...never seen posters on here put their location name when referring to them
Milkyway deal might be AmberwolfLocation:
Coordinates: 33°52′48″N 117°55′43″W
Location:
Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
ebike11 said:GPS??? To send a hitman..no thx jk