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    [Official] Armata Discussion thread #5

    Hole
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    Post  Hole on Thu 12 Nov 2020, 02:27

    This project will cost more then there new subs. Very Happy
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    calripson

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    [Official] Armata Discussion thread #5 - Page 18 Empty 2035

    Post  calripson on Thu 12 Nov 2020, 04:30

    By 2035, America will have gone broke, the US dollar will no longer be the world reserve currency (replaced by a digital global currency), and no one will remember your inane posts.
    kvs
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    Post  kvs on Thu 12 Nov 2020, 10:25

    LMFS wrote:All power conversion electronics involved do not like high temperatures, batteries hate it too. With new technology for the power accumulation and SiC electronics a hybrid IFV or tank shoud be doable, the idea is clear, but all the technological pieces must fall in its right place before it turns a reality

    A hybrid system is not the same as a plug-in hybrid with a large battery. Battery technology is still too crappy to use for tanks and trucks.
    So there is no need to cool some bank of lithium cells. And an electricity generator in a hybrid system does not need cooling. I think you
    are confusing a sine-wave power generator with a hybrid power train. That is a DC to AC system which does use electronics. A hybrid
    power train is pure DC running DC electrical motors.

    LMFS
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    Post  LMFS on Thu 12 Nov 2020, 15:57

    kvs wrote:A hybrid system is not the same as a plug-in hybrid with a large battery.    Battery technology is still too crappy to use for tanks and trucks.
    So there is no need to cool some bank of lithium cells.

    True, yet there is a need for a certain exchange storage to allow for the acceleration of the electric motors to be decoupled from the ICE operation, since the idea is that the later remains operating a the optimal regime. So of course the need for storage is minimal compared to a full electric vehicle but exists nevertheless. It can be done with flywheels or capacitors, too.

    And an electricity generator in a hybrid system does not need cooling.   I think you are confusing a sine-wave power generator with a hybrid power train.   That is a DC to AC system which does use electronics.    A hybrid power train is pure DC running DC electrical motors.

    There are several types of motors that can be used, induction or BLDC normally. In any case there is the need for power electronics (like B6 bridge) managing the motor's revs and torque.
    GarryB
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    Post  GarryB on Thu 12 Nov 2020, 19:44

    The US is reportedly preparing a groundbreaking successor to Abrams, which will overtake all competition.

    What the US is best at... PR and BS.

    Do they mean ground breaking because it is 120 tons?

    On a positive note it is nice to see they admit they are behind... despite already spending ten times more on "defence" than the Russians do... perhaps the solution is to spend 100 times more on defence... the best solution to corruption is to try to throw more money at the problem than the criminals have the capacity to take and hide... it is like sanctions on Russia... hasn't worked yet but a few more sanctions or more money and it will work like a charm...

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    lyle6
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    Post  lyle6 on Thu 12 Nov 2020, 20:29

    If diesel-electrics are really that good, then they ought to have replaced most diesel direct drives in low end torque applications a long time ago. Instead they are still relegated to niches involving very large platforms such as haul trucks for mining, and locomotives. Almost anything not involving hauling immense payloads across clear routes uses a mechanical transmission. This seems curious, since the mechanical transmission is the greatest source of failure in vehicles, and better yet, the electric motor displays superior acceleration performance at low speeds while consuming less fuel. It almost seems as if there are other considerations that give the edge to direct drives and make them far more usable than their hybrid cousins when it comes to certain tasks...

    Requirements like high density of components. This one's pretty high up on the list if you're a tank and for good reason. Internal volume is at a premium for armored vehicles. A diesel-electric drive might not have a mechanical transmission but it has a bulky generator and motor set, plus the associated power electronics (necessary if you want to step up voltage and minimize ampere losses, at least) and cooling. A larger internal volume would see weight specs spiral up as you have to pile on more and more armor to maintain decent protection coverage. Its pretty telling that the Russians are considering an articulated design for their hybrid powered Armata successor - it effectively doubles the internal volume available to the vehicle while avoiding the penalties of overly long hulls. However if the same size is to be maintained, at some point it makes zero sense to go for a much efficient powerplant when an even smaller volume and weight of fuel could maintain the same range albeit much lossy. This passes the strain on your logistics but it does result in a much smaller and lighter vehicle, which in of itself poses massive advantages in other areas.

    Another huge requirement is reliability. Mechanical transmissions are prone to failure, but most issues are readily fixable on the field. The technology is much more mature, and typically there are more people more familiar with mechanical issues than electrical ones. Hybrids in contrast are relatively immature technology with lots of teething yet to be resolved. The electric motors for example exhibit several failure modes that aren't necessarily found or as damaging in mechanical transmissions. There is a very real possibility for instance, that in case of strong transverse impacts on the suspension that the rotor could breach the tight armature gap and come into contact with the stator. Moisture is also a possible problem, especially since fording rivers is an essential capability and the hot windings can collect moisture from the air in cold and or humid environments.

    Of course none of this means that the direct drive is to stay forever either. Eventually a much better technology would replace it, but if that is to happen the benefits must more than outweigh the cons for users to shift. Personally I'm betting on direct hydrocarbon fuel cells that combine the high energy density of hydrocarbon fuels with all the benefits of an electric drivetrain but that's just me. We'll just have to wait and see what will out eventually.

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    LMFS
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    Post  LMFS on Fri 13 Nov 2020, 03:55

    lyle6 wrote:If diesel-electrics are really that good, then they ought to have replaced most diesel direct drives in low end torque applications a long time ago. Instead they are still relegated to niches involving very large platforms such as haul trucks for mining, and locomotives. Almost anything not involving hauling immense payloads across clear routes uses a mechanical transmission. This seems curious, since the mechanical transmission is the greatest source of failure in vehicles, and better yet, the electric motor displays superior acceleration performance at low speeds while consuming less fuel. It almost seems as if there are other considerations that give the edge to direct drives and make them far more usable than their hybrid cousins when it comes to certain tasks...

    The reason may perfectly be superior complexity and cost, and difficulty to do proper maintenance, only when the savings are very big or the machinery very expensive it makes enough sense to get industry switching to something new. Once such pioneering applications bring the reliability up and costs down, it will expend further I guess.
    GarryB
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    Post  GarryB on Fri 13 Nov 2020, 12:16

    Often there are other factors.... like ventilation requiring electric forklifts instead of diesel powered... or with trains some parts of the track are electrified and other parts are not so a diesel electric design makes sense.

    The thing is that diesels are generally quite big and heavy for the power they generate, but for quite some time there really was no alternative because electric motors simply didn't have the torque or performance to be a real alternative.

    These days batteries are not up to it to be the sole power source, but gas turbines are much smaller and lighter than any diesel engine with the same amount of power... the traditional problem has been that when you work a GT hard stopping and starting all the time like a bus does and a truck needs to in traffic then the performance drops and the fuel economy is awful, but when the GT just runs a generator and the vehicle is electric drive then things change dramatically... most of the time the GT can idle and together with the batteries drive the vehicle, but when running down hill you actually generate extra power from the wheels rather than consume power for propulsion. Heat generated from the GT can use waste heat energy for heating up the vehicle in cold climates... if you really wanted to go green the GT could run on LNG or even hydrogen... and with the latter you could have a few fuel cells to further boost performance when needed.
    lyle6
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    Post  lyle6 Today at 15:00

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