When the operating voltage is lower than the transformer rated voltage, in general, the transformer will not have any adverse effects, of course, can not be too low. Mainly due to user has certain requirements on voltage quality.
When the transformer operating voltage is higher than the rated voltage, the saturation of the core will increase as the voltage increases, resulting in serious distortion of the voltage and flux waveforms, no-load current increases accordingly. After the core is saturated, the harmonic value in the voltage waveform is also greatly increased. What's the effect?
First, cause the user current waveform distortion, increase the additional loss on the motor and the line.
Second, the harmonic resonance phenomenon may be occurred in the system, lead to overvoltage damage to the insulation.
Third, the line of high harmonics on the telecommunications lines will produce interference and affect the normal work of telecommunications.
Therefore, the rise of operating voltage on the transformer is unfavorable for user and transformer, therefore, regardless of where the voltage tap position, the transformer plus a voltage should generally not exceed the rated voltage of 105%.
