voltage drop on the output side of a transformer can effect the input side (primary ).

Question

While repairing a ac to dc power linear power supply I saw an issue of less voltage than rated value on one phase on the input(primary) side of transformer and a question arose in my mind that can voltage drop on the secondary coil of transformer (by some reason) can cause the voltage drop on the primary coil. However the issue was due to a fuse isn't proper installed.

aswinvenu · Accepted Answer

When you say primary - it means the mains line (110 or 230Volts) voltage right? Drop in the secondary side is understandable. Open circuit voltage in the secondary will be higher than the voltage when you load the circuit. Not sure about the drop in the primary! If your mains line has enough capacity it should not drop. Only If you are loading your power supply to some crazy wattage and your mains can't handle such high load then primary will voltage will drop. Can't think of any other situation where the primary voltage dips.

aswinvenu · Answer

Sorry, So you are saying that the 20Amp fuse on the primary was causing the issue? If you don't mind can you explain what you meant by "not properly installed". Loose contact?

voltage drop on the output side of a transformer can effect the input side (primary ).

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