Let’s say the machine lifts it up at a rate of 1 meter per second. So power needed would be 1000 x 1 = 1kW. But this is the power needed without frictional and other losses. Fairly assuming that the motor and pulley assembly is 80% efficient, actual power the motor pumps in from the source would be 1000/0.8 = 1.25kW.
How do you calculate elevator power?
The work done by the elevator over the 100 meters is easily calculable: W = mgh = (1000)(9.8)(100) = 9.8×105 Joules. The total time of the trip can be calculated from the velocity of the elevator: t = = = 25 s. Thus the average power is given by: P = = = 3.9×104 Watts, or 39 kW.
How do you calculate the power of a motor?
Power = (Force x Distance) / Time
For electric motors, power or horsepower can be calculated from the torque and speed. For example, if you have a motor rated for 3,000 RPM and 6 in-lbf then the horsepower is calculated below.
How is power calculated?
Power is a measure of the amount of work that can be done in a given amount of time. Power equals work (J) divided by time (s). The SI unit for power is the watt (W), which equals 1 joule of work per second (J/s).
Is work done on a person in an elevator?
The elevator has to perform more work in the moment the person is accelerating upwards, but then again less work when stopping at the top, i.e. decelerating. In total, the work performed by the elevator is therefore the same as if the person was standing still the whole time.
How much power does a elevator use?
The elevator controller uses about 83 watts all the time, even when the elevator is idle. That’s about $130 per year without even moving! Going up uses almost 40 times as much power as going down. Going up 5 floors uses about 500 kilowatt seconds and costs about $0.03.
How much power does a 7.5 hp motor consume?
Let us assume that motor is operating at full load so it will consume 7.5 hp or 5.59 or 5.6 kW approx. Let us assume motor has efficiency of 90 %, motor at full load gives around 90 % efficiency, so the power input to motor is 5.6/0.9=6.22 kW. Energy consumption in 2 hrs = 6.22×2=12.44 KWh or 12.44 unit.
What is the formula for calculating rpm?
How to Calculate Motor RPM. To calculate RPM for an AC induction motor, you multiply the frequency in Hertz (Hz) by 60 — for the number of seconds in a minute — by two for the negative and positive pulses in a cycle. You then divide by the number of poles the motor has: (Hz x 60 x 2) / number of poles = no-load RPM.
What is the efficiency of motor?
For an electric motor, efficiency is the ratio of mechanical power delivered by the motor (output) to the electrical power supplied to the motor (input). Thus, a motor that is 85 percent efficient converts 85 percent of the electrical energy input into mechanical energy.
What is the relationship between work and power?
Work is the energy needed to apply a force to move an object a particular distance, where force is parallel to the displacement. Power is the rate at which that work is done.
What would we need to know to calculate both work and power?
To find work we need to know energy and time; to find power we need to know energy and distance. To find work we need to know velocity and distance; to find power we need to know distance and time.
How much work can be done in 30 seconds by a 1000 watt microwave?
How much work can be done in 30 seconds by a 1000-watt microwave oven? 30,000 joules of work can be done.
Is normal force a conservative force?
The normal force is closely related to the friction force. Both are non-conservative forces, which can be seen when a ball bounces.
Why do you feel heavier in an elevator going up?
If you stand on a scale in an elevator accelerating upward, you feel heavier because the elevator’s floor presses harder on your feet, and the scale will show a higher reading than when the elevator is at rest. On the other hand, when the elevator accelerates downward, you feel lighter.
Can work be done by normal force?
No work is done by the normal force or gravitational force since the vectors are perpendicular to the direction of displacement. On the other hand, the friction force is parallel to the surface, and does work on the hockey puck. However, the friction force produces negative work.