Table of Contents
- 1 How are Interpoles connected in relation to the armature?
- 2 What are the functions of Interpoles and how are the interpole windings connected?
- 3 Where are the commutating poles situated in a DC motor and how are they connected?
- 4 What is the relationship between field current field flux and output voltage?
- 5 What type of connection is made in between the inter pole and the field winding?
- 6 How are armature reactions corrected?
- 7 What is a main field pole?
- 8 What is commutation in a motor?
- 9 How are the interpoles connected to the armature?
- 10 Why are the magnetic poles of the Earth not the same place?
- 11 What happens to the field poles in a DC machine?
How are Interpoles connected in relation to the armature?
The interpoles are connected in series between the armature and series winding. It is physically located beside the series coil in the stator. It is made of wire that is the same gauge as the series winding and it is connected so that its polarity is the same as the series winding pole it is mounted behind.
What are the functions of Interpoles and how are the interpole windings connected?
Interpoles are wired in series with the armature. Any changes in the armature current due to armature reactance, loading, or self-inductance pass through the interpole windings. This creates a changing magnetic field equal to and opposite that of the armature, thereby cancelling the effect.
What is the function of inter pole?
Interpoles in DC machine has basically two functions: Automatic neutralization of cross magnetization due to armature reaction. To counter and cancel reactance voltage in the coil undergoing commutation.
Where are the commutating poles situated in a DC motor and how are they connected?
These are the small magnetic poles placed between main poles mounted to the stator of the machine. These are attached in series connection with the armature. As load current causes back e.m.f. , these commutating poles neutralizes the position of the magnetic field.
What is the relationship between field current field flux and output voltage?
By increasing the field current, field flux can be increased. By control ling the direction of field current through the coils, the magnetic polarity is established. Output voltage level is controlled by the speed of the rotating armature and strength of the magnetic field.
What is armature reaction proportional to?
Armature reaction drop is the effect of a magnetic field on the distribution of the flux under main poles of a generator. This effect is known as armature reaction and is proportional to the current flowing in the armature coils.
What type of connection is made in between the inter pole and the field winding?
03․ What type of connection is made in between the inter-pole and the field winding? Series.
How are armature reactions corrected?
The effect of armature reaction can be neutralized by use of compensating winding. It is always placed in series with armature winding. The armature ampere conductors under pole shoe must be equal to compensating winding ampere conductors which will compensate armature mmf perfectly.
What is a field pole?
[′fēld ‚pōl] (electromagnetism) A structure of magnetic material on which a field coil of a loudspeaker, motor, generator, or other electromagnetic device may be mounted.
What is a main field pole?
What is commutation in a motor?
The process of commutation in a synchronous motor is that of switching between the phases. It is possible to switch between the phases in such a way that the winding will alternately attract and repel the permanent magnets to create the desired motion through Lorentz Law.
What is the relationship between field current and armature current?
The field current (and hence flux) can be controlled by either adjusting the field circuit resistance or the field supply voltage. For a separately excited machine, the armature current equals the armature terminal current.
How are the interpoles connected to the armature?
Interpoles: Interpoles are the small auxiliary poles placed between the main field poles. Winding on the interpoles is connected in series with the armature. Each interpole is wound in such a way that its magnetic polarity is same as that of the main pole ahead of it.
Why are the magnetic poles of the Earth not the same place?
Earth’s magnetic field is tilted a little bit. If we pretend that Earth’s magnetic field is made by a giant bar magnet, that bar magnet would make an angle with Earth’s spin axis. That angle is about 11 . That’s why the magnetic poles and the geographic poles are not in the same place.
Why is the polarity of an interpole always the same?
This creates a changing magnetic field equal to and opposite that of the armature, thereby cancelling the effect. Polarity of an interpole depends on the direction of rotation. The interpole’s polarity will always be the same as that of the main pole which precedes it.
What happens to the field poles in a DC machine?
Field poles are de-energised. Now, when a DC machine is running, both the fluxes (flux due to the armature conductors and flux due to the field winding) will be present at a time. The armature flux superimposes with the main field flux and, hence, disturbs the main field flux (as shown in third figure the of above image).