Usually when our washing machine has no power and does not spin, it is because the capacitor which uses the washing machine engine is defective and must be replaced. If you want to know which is the right capacity for the capacitor you have to buy we suggest you make the following calculation that will solve the problem of how to calculate the capacitor capacity of a washing machine motor.
Firstly you must observe the power of the washer engine. In domestic washing machines it is usually in the range of 150 watts to 300 watts, and it is usually on a plate attached to the motor. Once you've found your motor plate washer, grab a calculator and performs the following calculation:
Imagine that we have a 150 W motor and cos fi = 0.85 (a typical value)
Power = V x I x cosfi
I = 230 x 150 x 0.85
I = 0.767 Amperes
The apparent power (sum of active power + reactive power 150W ) = V x I = 176 VA
Calculation of inductive reactance (XL):
Apparent power = I ^ 2 x XL;
XL = apparent power / I ^ 2 = 176 / 0.76 ^ 2 = 305 Ohm
We calculate the coefficient of Rectifiers (L)
XL = 2 pi f L
We will take European frequency value 50 Hz, be careful because there are a lot of countries in which this value is 60 Hz.
305 = 2 x 3.1415 x 50 x L
L = 0.97 Henries
Calculating the capacity of the capacitor of the washer engine:
XL = 1 / (2 x pi x frequency x C)
C = 1 / (2 x pi x frequency x XL)
C = 1 / (2 x 3.14159 x 50 x 305) = 10.43 uF (micro Farad)
The value that we have found in this calculation is the typical capacitor that is usually placed in parallel to the motor of the washer. I hope this theoretical tutorial has been helpful.