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    Torque and Power

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    Table 1 shows a set of torque-speed measurements for a d.c. electric motor intended for use in an electric wheelchair. Data of this type is used by manufacturers to help specify motor performance.

    Table1
    Speed /rpm..............600..........1200......1850..........2400.......3050.........3700
    Torque /Nm..............5.51..........4.53.......3.75..........2.94........2.09.........1.08

    (a) Use the data in Table 1 to plot a suitable graph and obtain the five missing pieces of information, labelled (i)-(v), in the motor specification chart shown in Table 2.

    Table 2
    .................Stall....................No Load................Maximum Efficiency (Effic)
    Operating
    Volt /V.......Torque...Current....Speed.....Current...Torque....Speed...Current...Output
    ................./Nm....... /A.........../rpm ......./A......... /Nm....../rpm....... /A......(Effic)/%

    24................(i)........140............(ii)..........5.2.........(iii).......4000.......(iv).........(v)

    (b) One of the design requirements for the wheelchair states that the motor must be able to supply 40 Nm of torque at 100 rpm. Determine whether this particular motor has the power to meet that requirement.

    © BrainMass Inc. brainmass.com December 24, 2021, 11:26 pm ad1c9bdddf
    https://brainmass.com/math/logic/torque-power-569070

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    SOLUTION This solution is FREE courtesy of BrainMass!

    Speed /rpm Torque/Nm
    0 6.31
    600 5.51
    1200 4.53
    1850 3.75
    2400 2.94
    3050 2.09
    3700 1.08

    4000 0.717

    slope = -0.001
    y intercept 6.31

    y = -.001x + 6.31

    y = -.001 ( 4000) + 6.31
    0.717
    y= -.001 (5000) +6.31
    -0.04

    The torque of motor is proportional to the current
    flowing through it ( T = i)

    The angular velocity of motor is proportional to the voltage across it ( w = v)

    The electrical power of current I and voltage is I s Pw = T X w

    Pw= power
    T= Torque
    w = angular velocity
    Angular speed =P/T

    Maximum Efficiency
    Operating Stall No load Current /A Torque/Nm Speed / rpmC Current/A Output power/W Efficiency/ %
    Voltage Torgue/Nm Current Speed

    24 i)0.144 140 ii)6350 5.2 iii) 7.53 4000 18 iv) 30120 v) 62.99

    20.37 oz -inch

    Speed = P/T
    T * Speed = P
    T = P/Speed
    T = (-20.37 /6350 * speed + 20.37
    T= (-20.37 /6350* 4000 +20.37
    7.538503937

    Power = T X angular speed
    Power = 7.53 * 4000
    30120

    Motor must supply 40 Nm of torque at 100 rpm.
    Power = T X angular speed
    Power = 40Nm X 100 rpm
    Power = 4000 Watt

    Divide the Speed with the load with the no load speed
    % Efficiency = 4000/6350 * 100%
    62.99212598

    Since the motor above has a total Output Power of 30120 Watts, it should be enough to meet the requirement of above

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 11:26 pm ad1c9bdddf>
    https://brainmass.com/math/logic/torque-power-569070

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