Accleration time for electric supercharger

[arslanpersona]

Hello everybody..

I am stuck with a question here. I have to estimate time for an electric supercharger to reach from 40-120k rpm. Impeller inertia is negligible.
Max torque=2 Nm, bearing drag profile=0.001 Nm/krpm, diameter=30mm, Lenght=100mm
Shaft is solid steel with density =7.85 kg/cm3


Can anybody please help me with this. Thanks in advance

 

[berkeman]

Hello everybody..

I am stuck with a question here. I have to estimate time for an electric supercharger to reach from 40-120k rpm. Impeller inertia is negligible.
Max torque=2 Nm, bearing drag profile=0.001 Nm/krpm, diameter=30mm, Lenght=100mm
Shaft is solid steel with density =7.85 kg/cm3


Can anybody please help me with this. Thanks in advance

What is the context of the question? What is the application? What is your technical background? We can be of more help if we know more...

 

[arslanpersona]

I am a mechanical engineering graduate. Dont know much about electric motors but will understand if somebody put me in right direction.

 

[jim hardy]

You can calculate its moment of inertia

but what about the wind drag? It's a fan or pump of some sort. You are better versed in those than i am.

And what do we know of motor? All motors have a torque vs speed curve. It will accelerate until torque = drag, and torque = f(speed).

 

[alphysicist]

.Hello there,

I can provide a response to your question about estimating the time for an electric supercharger to reach 40-120k rpm. First, we need to consider the factors that affect the acceleration time of the supercharger. These include the torque, bearing drag, and the physical characteristics of the supercharger.

Based on the information provided, the maximum torque of the supercharger is 2 Nm, which means that the supercharger has enough power to accelerate quickly. However, the bearing drag profile of 0.001 Nm/krpm could potentially slow down the acceleration process.

The diameter and length of the supercharger also play a role in its acceleration time. A larger diameter and length may result in a longer acceleration time due to the increased inertia.

To estimate the acceleration time, we can use the following equation:

t = (2π√(I/τ)) / (ω1 - ω0)

where t is the acceleration time, I is the moment of inertia (calculated based on the physical dimensions and density of the supercharger), τ is the torque, ω1 is the final angular velocity (120k rpm), and ω0 is the initial angular velocity (40 rpm).

Based on this equation, we can see that the acceleration time is directly proportional to the moment of inertia and inversely proportional to the torque. This means that a higher moment of inertia or a lower torque will result in a longer acceleration time.

Without knowing the exact moment of inertia of the supercharger, it is difficult to provide an accurate estimate. However, based on the given dimensions and density, we can assume that the moment of inertia is relatively low, and the acceleration time should be relatively short.

I hope this helps with your question. Keep in mind that there may be other factors that could affect the acceleration time, such as the power source and efficiency of the supercharger. Further research and experimentation may be necessary to obtain a more precise estimate. Good luck with your project!