Binder
Well-Known Member
An electric motor can generate 100% of it's torque at zero RPM. How much wrk is it getting done?
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Binder--> horsepower & torque
- Thread starter Glenn
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An electric motor can generate 100% of it's torque at zero RPM. How much wrk is it getting done?
Binder
Well-Known Member
Far from true. 500HP is 500HP so all other things being equal they would tie in a quarter mile.
Trains are Deisel-electric for several reasons but this isn't one of them.
Binder
Well-Known Member
Because regearing puts your engine in it's useful RPM range. Torque doesn't move anything. Torque can't move anything without RPM. Torque plus RPM IS horsepower by definition.
Binder
Well-Known Member
I don't need a breaker bar to turn the world I have the internet!:flipoff:
Binder
Well-Known Member
Now to add o the confusion......Torque IS needed and here's what for.......
A stopped wheel is not turning at any RPM. To move it from a stop a specific torque value is required. This is called break free torque. It's a will or will not move deal....Lets say for example the torque needed to move a specific wheel is 1000 ft lbs. 999 ft lbs will not move it. 1000 ft lbs will move it and 20,000 ft lbs will move it. Whether it's 1000 or 20,000 doesn't matter as this is a go or no-go situation. Keep in mind this is torque at the wheel. How fast it moves or how fast it accelerates is a function of horsepower and horsepower alone...
Now given that there is a very simillar thing happening while driving down the road as well. A wheel while it's turning requires a specific amount of torque to continue to turn. Here again it's a go or no-go situation. This has nothing to do with how fast it turns or how fast it accelerates/ decelerates. As long as torque is above the needed number the wheel has potential to continue to turn. Drop below this number and you're either going to need to downshift or coast to a stop. This comes into play when rolling into a hill that gets steeper as you go. Most other times it's not an issue as the characteristics of a internal combustion engine used in cars/ trucks with a gear train make it so almost always will you have the needed torque at the wheel.
A stopped wheel is not turning at any RPM. To move it from a stop a specific torque value is required. This is called break free torque. It's a will or will not move deal....Lets say for example the torque needed to move a specific wheel is 1000 ft lbs. 999 ft lbs will not move it. 1000 ft lbs will move it and 20,000 ft lbs will move it. Whether it's 1000 or 20,000 doesn't matter as this is a go or no-go situation. Keep in mind this is torque at the wheel. How fast it moves or how fast it accelerates is a function of horsepower and horsepower alone...
Now given that there is a very simillar thing happening while driving down the road as well. A wheel while it's turning requires a specific amount of torque to continue to turn. Here again it's a go or no-go situation. This has nothing to do with how fast it turns or how fast it accelerates/ decelerates. As long as torque is above the needed number the wheel has potential to continue to turn. Drop below this number and you're either going to need to downshift or coast to a stop. This comes into play when rolling into a hill that gets steeper as you go. Most other times it's not an issue as the characteristics of a internal combustion engine used in cars/ trucks with a gear train make it so almost always will you have the needed torque at the wheel.
Money Mark
Well-Known Member
- Joined
- May 19, 2006
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HP and TQ are :rb:
WHITE TRASH1
fruit stripe
No work is being done at zero rpm but as soon as anything over stall is achieved work is being done. More torque just means work can be done at a greater speed.
More torque = less gearing needed to do work. Sure a 5hp briggs & stratton can make a train move but at what speed? Even with an infinitely variable transmission it won't have the power to move a train with ANY semblance of speed. Gearing can't make up for lack of power. Hence a lexus V8 going into the yota where a 22re used to live. Even with 186:1 before the converter entered the equation it would barely move. :haha:
Binder
Well-Known Member
As soon as anything over stall is achieved the wheel is turning. A turning wheel is measured in HP. Torque isn't a measure of work at all HP is a measure of work.
You're so very close to getting it, you just don't know it.:;
"Power" and "speed" are both synonymouse with "horsepower". Torque has no speed.
Absolutely correct!!:cheer: Gearing multiplies torque and cannot make up for lack of power.
Binder
Well-Known Member
Here's another thing for some of you guys to chew on....Using Nowires example above, two cars have 500 HP, weigh 4000 lbs and run a quarter mile....Now work this backwards. Two cars weighing 4000 lbs run the quarter mile. Take the elapsed time and you can calculate how much HP it took to do the work. The answer is 11.65 seconds.
Notice that torque isn't needed to figure this out! Torque doesn't matter!
http://robrobinette.com/et.htm
Notice that torque isn't needed to figure this out! Torque doesn't matter!
http://robrobinette.com/et.htm
TreeClimber
Well-Known Member
Not always
Binder
Well-Known Member
Yes always. Can you explain differently? Sure there are variables with losses due to friction but that's secondary to the principals involved.
TreeClimber
Well-Known Member
And this is not a valid amount of facts.
A 4000 brick will need more HP than a 4000 arrow due to the coeffecient of drag (aerodynamic drag, friction, etc)
TreeClimber
Well-Known Member
Sometimes an 'underdrive' transmission does not multiply torque, but rather divides torque. Ergo. NOT always.
edit: for the purpose of general discussion, 'multiply' is meant as to 'make larger', such as the statement: 'go forth and multiply'.... and 'divide' means to 'make lesser', such as the statement: 'divide and conquer'.
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Binder
Well-Known Member
All other things being equal....
Binder
Well-Known Member
Either way it's multiplied. Sometimes it's multiplied by less than one.:;
On that..............
A big block will always beat a small block with equal HP, weight. gearing
No one figures torque for the same reason that this thread is still going on. There are lots of factors when coming up with a torque figure. Ask anyone that has put over 15g into a motor and when it is on the dyno. The first thing that comes out of their mouth is
whatthe?
Well-Known Member
If once something is moving torque doesn't matter, then why do low HP diesels with high torque numbers out pull gassers on the hills? My 300 HP (365ftlbs) chevy will beat my friends dodge 250HP (440ftlbs) in a drag race. But we hook up 8,000 lb trailers, he owns me on the hills? I have more HP's can keep the RPM's where max is made. We have the same gearing. I understand torque as twist. Diesels make more twist therefor they can do more work (pull a heavy trailer). My gasser is faster because it can make the twist faster as long as there is not a lot of work to do (unloaded truck). Comments? Corrections?
horsepower is a fictional number created by man to express pressure across a length of time.
horsepower is a mathematical function of torque and time.
torque moves things, horsepower tells you how fast.
gearing allows low torque /high horsepower to do the same job in the same time as as high torque/low hp
horsepower is a mathematical function of torque and time.
torque moves things, horsepower tells you how fast.
gearing allows low torque /high horsepower to do the same job in the same time as as high torque/low hp
Binder
Well-Known Member
:haha: Not chance!...If you are paying more attention to a torque curve at the dyno then you are wasting your time at the dyno.:;
Binder
Well-Known Member
See post 13 and post 25.......Also if a truck has more HP and is in the correct RPM to use it it will oupull a truck up a hill with less HP....All other factors being the same.
