can anyone help ?
Hello
Its been years since the grey matter was used for this type of math. Its true what they say if you don't use it you lose it. I can say that I cannot remember how to integrate.
So onto the problem, its a simple Time/Speed/Distance problem.
I have an A.C. motor that I need to accelerate to a certain rpm with a certain torque. Here is some figures
Torque = Nominal torque * ( Base speed / Max Speed )
Max Torque = Max torque * ( Base speed / Max Speed )
Nominal Torque = 175kNm
Max Torque = 438kNm ( for 15 seconds )
Nominal Torque @ Max Speed = 63kNm
Max Torque @ Max Speed = 156kNm
So in essence as the rpm increases the available torque decreases.
I now have a load to put on the motor.
If I have a torque of 260kNm ( This equates to a acceleration rate of 2.5m/s2) and I want to get to an rpm of 700rpm
At 700 rpm I only have available 75kNm nominal and 188kNm maximum
So I dont have enough power to accelerate at 2.5m/s2
The break point is at 505rpm.
From 0 505 rpm I can accelerate at a constant 2.5m/s2 because I have the max torque available
From 505 700 rpm for every increase in rpm I get a decrease in available torque.
Therefore from 505 700 the accelerate rate will reduce as the rpm increases.
What I need to calculate is the time it takes to accelerate from 0 700 rpm, Also the distance travelled to do this acceleration.
So I hope this made sense to someone, I am hoping someone can help me with a solution My goal is to put this into excel so I can automatically calculate these figures for different input data.
One other problem I can see, is for example if the example above 10 seconds and 7 meters to get to the required rpm. What if I were only 'allowed' 6 meters I would have to calculate what speed I could achieve and how long would it take.
I understand I'm probably asking a lot so if anyone could help that would be amazing. Even if you cannot solve it all put give me a few pointers that would also be fantastic.
Thanks