| electric drive [message #353773] |
Mon, 13 April 2020 12:50  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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To get the electric discussion out of Hal's discussion.
The motor referenced is 'synchronous' which indicates it's running on variable Hz A/C current developed in the inverter packaged in the wheel. In that it fits a caliper and disk, how much braking - if any - does it develop via regeneration? Assuming it doesn't, there isn't a great need for a battery pack. It would allow a smaller engine, but by how much is debatable. More to the point, what voltage do these things want? If it's a 75KW motor, at 100 Volts it wants 750 Amps. 12 volts would require 6250 Amps, both figuring no losses. The variable speed drives used in big air handlers are fairly efficient, we might expect to achieve 95% or better with this. This thing is gonna get hot one way or the other, which is why it's water cooled. Now we'll need hoses to the radiator and a pump or two. And some honkin' big cables.
The devil's in the details, of which we need more to play this mental game. So, what is a 300KW prime mover going to look like.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: electric drive [message #353774 is a reply to message #353773] |
Mon, 13 April 2020 13:29  |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Senior Member |
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You actually may even need a chiller to cool the drive system fluids like we use on our vehicles.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: electric drive [message #353783 is a reply to message #353773] |
Tue, 14 April 2020 07:15 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Again the details. If we get 95% efficiency - to assign a number - at full tilt of 300KW we'd have to shed 15KW as heat. 1 Watt = ~~ 860 calories/hour. 15KW would mean we'd need to shed 12.9 million calories of heat per hour. Anyone know thermodynamics? How much radiator would this take? Plus engine heat. I have no feeling as to whether this is a large amount of heat or a small amount relative to an auto engine. Anybody?
Normal running would be much less, if we stayed away from the Rockies we could use smaller components.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: electric drive [message #353791 is a reply to message #353773] |
Tue, 14 April 2020 15:02 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Let's see here,
743 Watts per Horsepower
2545 BTU per Horsepower (SAE)
3412 BTU per Kilowatt
Most of the automatic transmissions I did things with had a parasitic load in the 15Hp area.
So, at road load we are looking at a heat rejection of about 38KBTU.
That is only about 11kW you have to cool. So, we are not that far from where we are today.
A GMC seems to have a road load of about 30hp (, but who drives on level ground with no wind). Even still, and engine and generator package to do this should not be tough. And if you make it a true hybrid by adding load of LiFePo batteries to climb hills, this could be a good time.
In that part of my life, I ran a couple of WWII build T-2 Tankers. They were electric drive. The motor on the propshaft was a huge thing with like 120 poles, and the main unit generator ran at 3600 to make 60Hz power. There was actually a lot to these plants, but the real beauty was when came time to run the cargo pumps to unload, we just set the main unit on the ship's power buss and used it to run everything.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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