E-bike Project: Finding Torque for 25 kmph Vehicle with 120 kg Gross Weight

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Discussion Overview

The discussion revolves around determining the torque required for an e-bike project designed to achieve a speed of 25 km/h with a gross weight of 120 kg. Participants explore the necessary equations and calculations to assess whether a 250 Watts motor can meet these requirements, focusing on theoretical and practical aspects of torque and power in relation to vehicle performance.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant outlines the project requirements, including vehicle specifications and the need for torque calculations.
  • Another participant inquires about the methods already attempted to find the necessary torque.
  • A participant describes their approach using formulas to relate motor speed to vehicle velocity and attempts to calculate torque based on tractive effort and resistance factors, expressing uncertainty about their calculations.
  • There is a suggestion to consider the power output of a racing cyclist as a reference point for power generation.
  • Specifications for a different motor option are provided, highlighting its power and torque ratings, which may be relevant to the discussion.
  • A comment indicates that the thread may be referencing older discussions or information.

Areas of Agreement / Disagreement

The discussion does not present a consensus, as participants express varying levels of understanding and uncertainty regarding the calculations and requirements for the e-bike project.

Contextual Notes

Participants have not fully resolved the mathematical steps involved in calculating torque and power, and there are indications of missing assumptions or definitions related to resistance factors and tractive effort.

anas@pibeam
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This is my requirement for one of my projects on E-bike.
front wheel drive three wheeler with brushless DC geared motor.
vehicle speed = 25 kmph
Gross weight = 120 kg
front wheel dia = 30 cm
whether 250 Watts motor can able to achieve this requirement?
What equations has to be used to find out the torque required to drive the vehicle on flat road?
someone please help me out..
 
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What have you tried so far?
 
i have tried some basic formula to find whether the motor suits my requirements..but the answer is not coming
first i tried to find out the motor speed from velocity using
v=2*pi*r*N/60
then with that speed i found out the torque
p=2*pi*N*T/60
then i compared this one with
T=TE*r*RF
TE-Tractive effort
RF-Resistance factor
and P=F*v
F= mu*m*g
i am not sure where i had done the mistake
 
Do you need to use maths?

How much power can a racing cyclist generate? Google it.
 
Here's i given some specification-
  • Spoke to center (STC) technology allows better flex and traction on trails
  • Modern design with super slim profile
  • Industry-leading power-to-weight ratio
  • Power – 500W / 1000W
  • Torque – 25/50 Nm (18/37 lb-ft)
  • Weight – 3.9 kg (8.6 lb)
 
old thread alert.
 

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