Contents
How is PU value calculated?
Per Unit Calculation | Per Unit System Examples
- The per unit (PU or P.U.)
- The PU system of calculations was more prevalent in the past years.
- A PU value can readily be converted back to a voltage, power, or any other value as long as the base value is known.
- Per Unit = (Present value) ÷ (base value)
How do you calculate motor parameters?
For the calculated Lm = 754 uH, motor leakage inductances Lls = Llr = 76 uH and resistance Rs = Rr = 24 mΩ, the optimal slip is calculated equal to s = 5.1 Hz at rated motor speed.
How is pu impedance calculated?
Any per unit impedance will have the same value on both the primary and secondary of a transformer and is independent of voltage level. A network of per unit impedances can then be solved using standard network analysis. There are four base quantities: base MVA, base KV, base ohms, and base amperes.
What is the purpose of load test of induction motor?
The load test on induction motor is performed to compute its complete performance i.e. torque, slip, efficiency, power factor etc.
How to calculate the operating parameters of an induction motor?
Note: it is relatively straightforward to obtain the equivalent circuit parameters by testing. Typically this would involve a d.c. test, no-load test and locked rotor test. The simplified equivalent circuit allows us to calculate the operating parameters for an induction motor. Note: calculations are vector quantities.
What can you do with an induction motor equivalent circuit?
The simplified equivalent circuit allows us to calculate the operating parameters for an induction motor. Note: calculations are vector quantities. Should complex representation be used, then phase shift, power factors, etc. automatically fall out of the calculations.
Can a transformer be used to model an induction motor?
From the preceding, we can utilise the equivalent circuit of a transformer to model an induction motor. In the equivalent circuit R1 represents, the resistance of the stator winding and X1 the stator leakage reactance (flux that does not link with the air gap and rotor).
What is the phase impedance of an induction motor?
For the same induction motor at no load test example, the Volts per Hertz ratio is set 5 times lower than the nominal, that is 0.053. The respective results taken from Roborun+ utility are shown below: , while the equivalent phase impedance is Z = 0.081 Ω according to equation (4).
https://www.youtube.com/watch?v=tiSXUqez-Bs