torque vs chainspeed

[Chris-PA]

It would seem those methods would require you to calculate the horsepower, after measuring current or temperature rise?

OK, if calculating things is a problem then drive a generator and measure the watts with a wattmeter. You would of course have to calculate hp from watts. When one measures torque on a dyno, typically the actual measurement is voltage from a load cell which must then be converted to torque by knowing the how it is calibrated and how long an arm is used.

The discussion of how any of the terms are measured and if it is done directly or if further calculations are needed is a distraction from the issue of what the terms mean. There is a valid idea people are trying to express, which was well described by wcorey in comment #49 http://www.arboristsite.com/community/threads/torque-vs-chainspeed.271594/page-3#post-5178290 , but using the wrong terms just promotes confusion. It is not a trade off between torque vs. rpm, it all about power and and the shape of the power band.

 

[thomas1]

OK, if calculating things is a problem then drive a generator and measure the watts with a wattmeter. You would of course have to calculate hp from watts. When one measures torque on a dyno, typically the actual measurement is voltage from a load cell which must then be converted to torque by knowing the how it is calibrated and how long an arm is used.

The discussion of how any of the terms are measured and if it is done directly or if further calculations are needed is a distraction from the issue of what the terms mean. There is a valid idea people are trying to express, which was well described by wcorey in comment #49 http://www.arboristsite.com/community/threads/torque-vs-chainspeed.271594/page-3#post-5178290 , but using the wrong terms just promotes confusion. It is not a trade off between torque vs. rpm, it all about power and and the shape of the power band.

I guess this is your extremely verbose way of saying that HP cannot be directly measured? Even though I asked a simple question and you gave two solutions, neither of which were correct.

I don't think anyone is confused by the terms except you. People want a saw that has more power at the same RPMs. The way to have more power is to have more torque. Without torque there is no power as power is merely a calculated figure.

 

[Moparmyway]

This entire discussion is equivalent to asking "what is more important, voltage or current?", when in fact voltage x current = power and neither is more important.

Current plays a more vital role in that current is a limiting factor of conductors, not voltage
Current is limited in a circuit by fuses, breakers, overloads, and sometimes computer CT's, not voltage
Current is what heats up conductors to the point of melting the conductor or the conductors termination, not voltage
Current is limited by conductor size, not voltage

IMHO, torque can be measured easily, while horsepower MUST be calculated.
Even if HP was a given in an equation, it had to have been calculated in the first place

 

[Moparmyway]

OK, if calculating things is a problem then drive a generator and measure the watts with a wattmeter. You would of course have to calculate hp from watts. When one measures torque on a dyno, typically the actual measurement is voltage from a load cell which must then be converted to torque by knowing the how it is calibrated and how long an arm is used.

To this day I have never seen a wattmeter that took a direct reading without first calculating current multiplied by volts. All of the E-MON/D-MON meters I install use CT's to measure the current, then they calculate watts from the line volts. All old meters on houses use shunts or coils to reference or measure voltage and current, then display watt hours based on the strength of magnetic fields produced

Chads dyno just uses an arm ........... there is no voltage being produced

 

[HuskStihl]

We're talking past each other. Torque is more easily measured than power. Y'all are right. Measuring dynamic torque is not nearly as simple as measuring static torque (1 lb on a 1 ft bar), and dyno's typically drive an electrical, electromagnetic or hydraulic system and calculations of both torque and power are made from the data generated.
What I am saying is these are not independent things. If you tell me torque and RPM, I can tell you power. If you tell me power and rpm, I can tell you torque. Ease or difficulty in direct measurement does not affect the equation connecting the two. If you want power to be considered meaningless, and torque at a given rpm to be what is discussed, I'm fine with that. If it turns out that I'm just too stupid to be in this discussion, I apologize for confusing things. Off to work.

 

[Mastermind]

From 2007.....

without torque, there is no HPopcorn:

As this thread will fill with endless arguments about the same, here's a baseline to argue from

http://en.wikipedia.org/wiki/Horsepower

 

[wyk]

From 2014:

 

[Chris-PA]

I guess this is your extremely verbose way of saying that HP cannot be directly measured? Even though I asked a simple question and you gave two solutions, neither of which were correct.

You are apparently unaware that hp and watts are measures of the same thing - power. I guess if one measures temperature in Fahrenheit then it is not possible to know what the temperature is in Centigrade? Ever see a European engine power rating?

The way to have more power is to have more torque.

That is one way, as long as the rpm does not decrease more than the torque increases. You could also have more power without increasing the torque at all. Or you could increase the torque and lose power.

Current plays a more vital role in that current is a limiting factor of conductors, not voltage

Voltage drives the current flow - without voltage there will be no current. There are two variables, and just like with rpm and torque it is a fool's errand to try to decide which is more important to the product.

To this day I have never seen a wattmeter that took a direct reading without first calculating current multiplied by volts. All of the E-MON/D-MON meters I install use CT's to measure the current, then they calculate watts from the line volts.

Lots of ways to measure watts. How about this one:

Chads dyno just uses an arm ........... there is no voltage being produced

IIRC the arm presses on a digital scale. In the scale is a load sensor/piezo device, which produces a voltage....

In reality we don't measure much of anything directly. We measure length by counting marks on a stick. We measure temperature by noting how high a closed column of mercury or alcohol rises.

Power for a period of time is work. Torque over a period of time is not. Something spinning with no (or little) torque is not work either. Why do people feel the need to assign relative value to the two pieces that make up the whole? If one were more important than the other the equation would have to reflect that, but it doesn't.

 

[tree monkey]

From 2014:

can some one calculate how long it will take to cut a piece of red oak 22" using just this Graff?

 

[Moparmyway]

without voltage there will be no current.

Really ???
1. Then please explain how a neutral has full current without any voltage, and has been known to actually kill people who had your train of thought (on this matter)
2. Now you just eliminated eddy currents for everyones enjoyment, if what you stated was true

Lots of ways to measure watts. How about this one:
View attachment 399093.

A shunted coil .......... just like I stated in my previous post

IIRC the arm presses on a digital scale. In the scale is a load sensor/piezo device, which produces a voltage....

So if he used a non-electronic scale, what would you have to say ?


I love reading your posts, and usually agree with you on most things, but I just about have my PE in electrical engineering. Peace, my friend

 

[thomas1]

You are apparently unaware that hp and watts are measures of the same thing - power. I guess if one measures temperature in Fahrenheit then it is not possible to know what the temperature is in Centigrade? Ever see a European engine power rating?

How many horsepower in a 60w light bulb?

That is one way, as long as the rpm does not decrease more than the torque increases. You could also have more power without increasing the torque at all. Or you could increase the torque and lose power.

Or you could attempt to read what I actually wrote. Where I stated that the rpm remained the same, guess you missed that part? Must have been too busy patting yourself on the back.

People want a saw that has more power at the same RPMs. The way to have more power is to have more torque.

 

[thomas1]

can some one calculate how long it will take to cut a piece of red oak 22" using just this Graff?

I'd guess 3 seconds less than it took that jred in your 361 video.

 

[Mastermind]

can some one calculate how long it will take to cut a piece of red oak 22" using just this Graff?

Nope......

Just a purty graph.......to me it means nothing. It is fun to whip out and show off at certain times.

Wait.......we are still talking about chainsaws......right?

 

[Gypo Logger]

Randy, what do you mean by potato?
Just asking.

 

[Chris-PA]

Really ???
1. Then please explain how a neutral has full current without any voltage, and has been known to actually kill people who had your train of thought (on this matter)
2. Now you just eliminated eddy currents for everyones enjoyment, if what you stated was true


A shunted coil .......... just like I stated in my previous post



So if he used a non-electronic scale, what would you have to say ?


I love reading your posts, and usually agree with you on most things, but I just about have my PE in electrical engineering. Peace, my friend

I respect that you're going for your PE - I never did. I have spent 26 years designing equipment to measure current, voltage, power, etc on 3-pahse systems. If you believe there can be current flow in a conductor with no potential difference across it then I encourage you to review. There are a few laws that would be violated if that happened. I assure you that if current flows in the neutral, there is a voltage driving it.

I actually have no idea what point you are trying to make - I don't care in the least what method is used to measure torque or rpm or power. Use a spring scale instead of an electronic one - that indirectly measures force by pushing against a spring, and one must then calculate torque using a distance indirectly measured with calibrated marks on a stick.

All such methods will be indirect, and none of it is relevant to the point I was making - that whole thing was just Thomas doing his usual tactic of fishing for a "gotcha" angle so he could claim I'm wrong on some point and that then anything I say is wrong.

Rather than the way things are measured or how to use the equation, the point I was trying to get to was the meaning of the terms. Work is energy, which is power times time. Torque and rpm are just parts of what makes up power, are of equal importance, and in fact through gearing one can be converted into the other. If you want to do more work, you can increase either torque or rpm.

What changes the usefulness of the saw power band is how peaky it is - the shape of the plot of HP vs. rpm.

 

[wyk]

can some one calculate how long it will take to cut a piece of red oak 22" using just this Graff?

Lil more than 10 seconds:

 

[Chris-PA]

How many horsepower in a 60w light bulb?

A 60W bulb draws 0.081hp. Why?

 

[Moparmyway]

I assure you that if current flows in the neutral, there is a voltage driving it.

Please go to a neutral in any single phase 120 or 277 operating circuit and measure both the current and the voltage ................. I assure you that you are in for a surprise

I actually have no idea what point you are trying to make

^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

OK, because proper terminology matters.

 

[thomas1]

All such methods will be indirect, and none of it is relevant to the point I was making - that whole thing was just Thomas doing his usual tactic of fishing for a "gotcha" angle so he could claim I'm wrong on some point and that then anything I say is wrong.

No, I asked you a simple question, "How do you directly measure HP?"

You gave two methods to do so, neither of which directly measure HP. Now, rather than just saying you were wrong, you write in convoluted circles in an attempt to direct the attention away from the fact that you were wrong. Now your contention is that we don't directly measure anything.

Maybe if you spent a little more time actually paying attention, rather than trying convince everyone how smart you are, you'd be better off? Is the view that much better from your high horse?

 

[Trx250r180]

I measure tourque with one of these ,but i am a dumb junk man