What happens to the direction of the magnetic field about an electric current when the direction of the current is reverse?
What happens to the direction of the magnetic field about an electric current when the direction of the current is reversed? The magnetic field reverses direction at every point. A clockwise pattern of concentric circles becomes a counterclockwise pattern of concentric circles and vice versa.
What happens if you reverse the direction of the electric current?
The two poles of the permanent magnet remain the same, but the poles of the electromagnet reverse when the direction of electric current reverses. This pulls the electromagnet towards the permanent magnet. When the electric current changes direction, the same end of the electromagnet becomes its south pole.
Does a power supply can reverse the flow of current in the circuit Why?
A diode placed in series with the positive side of the power supply is called a reverse protection diode. It ensures that current can only flow in the positive direction, and the power supply only applies a positive voltage to your circuit.
What is the purpose of a reverse current cutout relay?
What is the purpose of a reverse current cutout relay? A) It eliminates the possibility of reversed polarity of the generator output current.
Where is the regulator on an A type field circuit generator?
A Type-A circuit has the voltage regulator on the ground side of the field coil. A Type-B circuit has the voltage regulator located on the power side of the field coil. In many late model vehicles the regulator is controlled by the PCM.
What happens in the series field coils of a DC generator when there is an increase in current flow?
If another load is added, more current flows and the pole pieces produce more magnetic lines of flux, which again increases the output voltage. Each time a load is added to the series generator, its output voltage increases.
Can a series motor be operated with no load connected?
At no-load very less current will be flowing in the winding i.e. very less flux will be developed in the machine and speed and flux being inversely proportional to each other speed rises to a dangerous value. So, it is not advised to start a series motor at no-load.
What do you understand by self excitation mode in DC?
Self-excited DC Generator is a device, in which the current to the field winding is supplied by the generator itself. In self-excited DC generator, the field coils may be connected in parallel with the armature in the series, or it may be connected partly in series and partly in parallel with the armature windings.
Can a series motor may be operated with no load connected?
Counter-electromotive force (CEMF) and back-EMF are names for the voltage induced into the armature of a DC motor. A series motor may be operated with no load connected.
What type of motor should never be operated at no load?
A series motor should never be started at no load. With no mechanical load on the series motor, the current is low, the counter-EMF produced by the field winding is weak, and so the armature must turn faster to produce sufficient counter-EMF to balance the supply voltage. The motor can be damaged by overspeed.
Which type of load is connected to the DC series motor?
DC Series Motors The series winding will have relatively few turns of larger wire or copper strip which are capable of carrying the full load current of the motor. On starting, because the windings are low resistance, a large current can be drawn producing a high starting torque.
When load is removed motor will run at the highest speed?
1 Answer. When load is removed, series motor will run at the highest speed.
What will happen with the increase in speed of a DC motor?
What will happen, with the increase in speed of a DC motor? a) Back emf increase but line current falls. So, with the increase in speed, the back emf also increases. Therefore, armature current is also decreased, in case of series motor, armature current is equal to the line or load current.
Which motor has best speed regulation?
DC Motor
Can DC motor run on AC supply?
The current in the armature winding is in phase with the magnetic field produced by the field winding. However, a dc series motor does not operate well on ac power. The motor has a low-efficiency power factor and runs with considerable sparking a low the brushes.