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The hum is generated by the magnetic field continually reversing at the frequency of the supply. 50Hz in Europe and 60Hz in the USA. This frequency is set by the speed of the turbines spinning magnets past wire coils of the alternators in the power stations.
The magnetic field in the AC machine or Transformers have coils which,although secured by being dipped in varnish, are still able to move slightly.The armature laminations are treated in a similar way but also vibrate at the line frequency and it is almost impossible to stop.You can only reduce it to a minimum by good design.
What else can I help you with?
What is the cause of Hum in AC Capacitors?
Hum is caused in (low frequency) AC capacitors by electrostatic forces between the capacitor's plates, causing them to vibrate.
What is AC welding machine?
An AC welding machine is one that uses electrical power from house or shop and has a controlled output in AC or Alternating Current.
Derive emf equation of a DC machine?
equation of ac machine
How AC is converted into DC in welding machine?
rectifyer
How does the variation of excitation of an alternator correct power factor?
The rotor of an alternator need a DC voltage applied to it to generate a magnetic field, this magnetic field will generate the AC power in the AC windings.The AVR(Automatic Voltage Regulator) is regulating this DC voltage so that the magnetic field is strong enough to maintain the output AC voltage. As soon as more current is drawn from the output, this output voltage will drop and a stronger magnetic field is needed to sustain the output voltage, so the AVR step up the exiting voltage to get a stronger magnetic field to compensate for the voltage loss in the AC windings.
What is the relationship between electrical frequency and magnetic field speed for an ac machine?
In an AC machine, the electrical frequency of the input power supply determines the rotational speed of the magnetic field, which interacts with the conductors in the machine to produce electrical power. The relationship between electrical frequency and magnetic field speed is directly proportional – an increase in electrical frequency results in a corresponding increase in the speed of the rotating magnetic field.
What is the cause of Hum in AC Capacitors?
Hum is caused in (low frequency) AC capacitors by electrostatic forces between the capacitor's plates, causing them to vibrate.
Can a DC motor work on an AC supply?
There is a motor that is known as Universal motor which works on DC or AC .You might find one in a drilling machine or a domestic grinding machine .But there is a disadvantage ,in that there will be sparking at the commutator between the brushes and the commutator segments due to a shift in the magnetic neutral axis while on AC operation.
How to Wind the stator of an AC machine?
How ti wind the stator of an ac machine
Is electromagnetism is possible with AC?
AC current creates an alternating magnetic field, consistent with the alternating voltage. The only way I know of using AC current to create a constant magnetic field is to rectify the AC into DC and then use that DC to create the magnetic field.
What is AC welding machine?
An AC welding machine is one that uses electrical power from house or shop and has a controlled output in AC or Alternating Current.
Definition of ac machine?
A machine that runs on an alternating current.
What is the name of a machine in which the magnetic field is provided by an electromagnet?
MRI machine
Why do power lines hum?
Power lines hum due to the vibration of the electrical current running through them, which creates a magnetic field that causes the wires to vibrate and produce a low-frequency sound.
What is used to read the information from the magnetic stripe?
Magnetic stripe readers
Do pickup covers make a different sound on a guitar?
reduces hum as it alters the magnetic field is what many will say
Derive emf equation of a DC machine?
equation of ac machine
