# Torque required to maintain velocity

• teage
In summary, a person is trying to find the power required to maintain a constant velocity using three values: 1) the torque to accelerate the drum, 2) the torque needed to hold the mass, and 3) the torque to accelerate the mass. The starting torque depends on what value you choose for acceleration. Assuming no friction, the person finds that the power required is 28.75 Kw.
teage
Hi guys,

I am designing (homework) a winch drum and am having a brain fart. i am trying to find the power required to maintain a constant velocity.

i have figured out that the torque required to lift the mass is in 3 parts:

1. torque to accelerate the drum = 241 N.m

2. torque required to hold the mass = 3531 N.m

3. torque required to accelerate the mass = 540 N.m

so the torque required to accelerate everything is 4312 N.m

power required to accelerate is 28.75 Kw

now i need to find the power to maintain a constant 4 m/s or 6 2/3 rad/sec with a drum diameter of 1.2m. i have found N to be 64rpm but I am not sure which torque to use to calculate the power.
i assume that the inertia torque can be left out along with the torque to hold the weight of the mass.
If so i am left with P=3.6Kw to maintain velocity. it doesn't seem to be enough considering the starting torque is 28.75Kw.

assume no friction.

Is this right?

Thanks

Hi teage,

As I understand you have the mass needed to be lifted (hopefully up) and it's intended velocity. That should suffice for your power computation.

teage
teage said:
If so i am left with P=3.6Kw to maintain velocity. it doesn't seem to be enough considering the starting torque is 28.75Kw.
Is this right?

The starting torque depends on what value you choose for acceleration, which you haven't stated. Please use the homework template or this thread will be closed.

Consider two cars, a Ferrari and a Toyota Corolla. They both require the same power to maintain highway velocity but Ferrari level acceleration requires Ferrari level power and results in a Ferrari level price tag.

Does the spec. require a Ferrari type winch or have you chosen too high an acceleration value?

Acceleration is now irrelevant. It has been accelerated and is traveling at a steady 4 m/s. have found the power required to accelerate using the total torque multiplied by omega. My question is which torque value out of the 3 do I need in order to calculate the power required for constant velocity. First u assumed I should use torque 3 but after sleeping on it I think logically that I should use the torque required to hold the mass which would give me a power of 23.54Kw to maintain velocity and 28.75 to accelerate. Does that sound right?

You don't need to use any torque value. The quickest way is via
P = Fv
Power equals force times velocity.

teage
teage said:
Acceleration is now irrelevant. It has been accelerated and is traveling at a steady 4 m/s. have found the power required to accelerate using the total torque multiplied by omega. My question is which torque value out of the 3 do I need in order to calculate the power required for constant velocity. First u assumed I should use torque 3 but after sleeping on it I think logically that I should use the torque required to hold the mass which would give me a power of 23.54Kw to maintain velocity and 28.75 to accelerate. Does that sound right?
The 23.54 kW is close enough. The holding torque was all that was needed. You could have obtained the mass from it and then go by Billy Joule's way for obtaining practically the same thing.

teage

## 1. What is torque required to maintain velocity?

Torque required to maintain velocity is the amount of force needed to keep an object moving at a constant speed in a circular motion.

## 2. How is torque related to maintaining velocity?

Torque is directly related to maintaining velocity because it is the force that causes an object to rotate, which is necessary for maintaining circular motion and a constant velocity.

## 3. What factors affect the torque required to maintain velocity?

The factors that affect the torque required to maintain velocity include the mass of the object, the radius of the circular motion, and the angular velocity of the object.

## 4. How can torque be calculated for maintaining velocity?

The formula for calculating torque required to maintain velocity is T = I*α, where T is torque, I is the moment of inertia, and α is the angular acceleration. This formula can be used for both linear and angular motion.

## 5. Can torque be reduced to maintain velocity?

Yes, torque can be reduced to maintain velocity by decreasing the radius of the circular motion or by decreasing the angular velocity of the object. In other words, reducing the distance from the axis of rotation or the speed of the object will decrease the torque required to maintain velocity.

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