超深數學提. 計時速

fatchickterian 發表於 2011-5-17 12:31

                               
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回復 hinwong 的帖子

oic, so which part is the sensor suppose to be sensing? the spur or the pinion  ...

應該係, 不過要裝到果塊野, 企起度,真係超難....

回復 fatchickterian 的帖子

All these factors are reflected in the measured revolutionary speed of belt (1300 rpm).
Yes, the power supplied by the motor are lost due to all the factors you mentioned. And this will reduce the final speed of the car. But these are all reflected in the measured speed, whether in the car or in the belt.
They are discussing a speed conversion question here (more or less a unit conversion), not really an Energy conversion question that you learnt in yr high school physics.

回復 buzzybee82 的帖子

No need. Because friction helps to turn the wheels and keep the car moving forward. Without friction, the wheels will slip... and all the calculations will be useless.
Air resistance will reduce the speed. However, this factor is reflected in the measured speed of belt already. Power supply from motor is lost, and it reduces the final speed of the whole transmission chain as a result.

回復 hinwong 的帖子

This may help. Let's define a few variables first:

G = Gear teeth on yr Diff (e.g. 38T)
B = Belt teeth on yr belt (e.g. 522T)
D = diameter of yr wheel with tyre on ( in mm)
Pi = 3.1416
W = measured revolutionary speed of belt (in rpm)
V = speed of car (in km/h)

V =  Pi x D x W x (B/G) x (60/1000000)

The final gear ratio plays no role in yr question. That's related to the conversion between motor's rotation and wheels' rotations.  

p.s. Measured speed of wheels = Actual speed of car (unless the tyre slips)

回復 singlau714 的帖子

Sorry no dis-respect, but could you please explain it again in chinese!!

回復 fatchickterian 的帖子

http://translate.google.com/

回復 singlau714 的帖子

ok the goole translator was useless!!

After reading your comment a couple of times (Sorry on dis-respect again!!), I think what you're trying say is that, the measurement of the speed (on the belt) has already included lost(s), so the final result should have already included all the lost(s).

And sorry, I must have missed out my unit conversions during high shool!! (did'nt pay attention until uni ha ha)

回復 fatchickterian 的帖子

Yes that's what I mean. btw, u can use the word "loss" to replace yr "lost(s)".
Modified from google translator:

所有你所提到的因素都反映在皮帶的測量速度（1300轉）。
是的，由 Motor 的能量轉換 將有 能量丟失, 這將減少最終車的速度。但這些均反映在測量速度，無論是在汽車速度或在皮帶速度。
他們正在有討論一個 速度轉換問題（或多或少是 單位轉換），而不是一個真正的能量轉換問題，和你高中物理學到的不同。

回復 singlau714 的帖子

oooh, thank you for the conversion and the grammar lecture!!

回復 singlau714 的帖子

Just because I love my energy and your knowledge is beyond my high school physics, it leads to my next question (sorry!).  So you saying to measurement of speed on the belt has already content lost factors.  How about anything after the belt? like the diff pulleys, is there any sound on the pulleys, is there any heat as well?? if there are sound and heat, does it mean there are "losses" as well?? I know these questions can go on and on. That's why I said earlier on "the factors are never clear"

回復 fatchickterian 的帖子

it can be anything that you can think of.  Limitation is that the sensor and the object to be tested must be within 1 mm.
I prefer to check the RPM of the spur gear.

回復 fatchickterian 的帖子

let us put it this way.
if there are no energy lost, the belt would have spin faster  > 1300 RPM
Because of the energy lost that you have mentioned, the belt turned at 1300 RPM only

Energy input  into the car = mechanical energy of car (belt spin at 1300 RPM) + energy lost ( sound, vibration , heat , etc)

hinwong 發表於 2011-5-15 23:25

                               
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sakura s
22t + 80t 大減, 齒比等於6.91
皮帶牙 20t (原裝)

Diff pulley teeth number/center pulley teeth number=a
spur gear teeth number/motor gear teeth number=b
motor rotation speed=c (in rpm)
Wheel circumference=d (in metre)
c/b=e
e/a=f
f*d=g
g/60=speed (m/s)

回復 OzAndy 的帖子

Ha ha ha 99.99 marks because there is no 100 markd for this type of answer ha ha

Sorry if I have offended anyone, just my area of interest, and can help putting my 5 cents worth in!! Thanks for your discussions!!

回復 fatchickterian 的帖子

never mind la.
anyone contribute a little bit, so that everyone can learn something from it

用雷槍測試最為準確,???

回復 chiyuen 的帖子

要問差人借....

是不是行車轉數（1300轉）

回復 yiuli2003 的帖子

皮帶轉數..