Figure —Armature reaction. Now you have two fields — the main field, view A, and the field around the armature coil, view B. View C of figure shows . These interpoles, being midway between main poles, are just opposite the The interpole windings are connected in series with the armature. Stator of a DC machine. ▫ Stator is the stationary part. ▫ Main poles as field winding. ▫ Further windings. ▫ Interpole. ▫ Compensation eliminate unwanted effects.

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LOAD on a motor is the physical object to be moved by the motor. Pages through By reversing either field or armature connections. If the ordinary resistance diverter were used, a sudden surge of current caused by a sharp increase in load would not divide between the interpole path and the diverter path in inverse proportion to their respective resistances; but, because of the high reactance of the interpole path, a disproportionately large portion of the surge current would flow through the diverter.

If their polarities be made the same as those of the armature poles opposite to them, and if their strength be made equal to that of the interpolf poles, then the distortion of the windingx field at the commutating point, as in Fig.

It maintains a constant speed under varying loads. This EMF opposes the applied voltage, and limits the flow of qindings current. Its speed varies widely between full-load and no-load.


Kimberly To avoid the commutation difficulty actually encountered in old-style generators, narrow poles called interpoles or commutating poles are used, as indicated in Fig. Such an improper division would cause the interpole field to fail interpoke rise in proportion to the armature current to be commutated, and would probably cause the commutator to flash over at the brushes.


Increasing shunt-field circuit resistance increases motor speed. Adding resistance in series with the armature windings reduces initial current.

All about EEE: What is the function of interpoles and how are its winding connected?

The armature poles are attracted to field poles of opposite polarity, causing the armature to rotate. It is very difficult for a designer to calculate the exact number of turns to be placed on the interpoles, and it is sometimes necessary to connect an adjustable diverter around the interpole windings to permit shunting of a part of the total armature current around those coils.

In a generator the interpoles must be of the same polarity as the main poles which they precede in the direction of rotation. The brushes are located on the no-load neutral plane.

The field strength varies with changes in armature current. They are the Gramme-ring and the drum-wound types. When the interple current is reversed, the current through the interpole is also reversed.

There are no differences. Controlling the starting resistance in a DC motor is accomplished either manually, by an operator, or by any of several automatic devices. It may then be removed after counter EMF has been built up. Excessive current will flow when DC voltage is first applied unless current is limited in some way. Automatic starters are not covered in detail in this module. High torque turning force at low speed. Nearly all DC motors have drum-wound armatures.

Therefore, the interpole still has the proper polarity to provide automatic commutation.

Motor will slow down. The device to be driven by the motor. The field strength is independent of the armature current.


Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. Interpoles and compensating windings are used to reduce the effect of armature reaction on motor operation. Direction of conductor movement rotationdirection of flux, and the direction of current flow. The following information provides a summary of the main subjects for review. The inductance of the coil tends to retard the wiindings of the coil current by generating a prolonging voltage.

It is not necessary to shift the brushes when there is an increase or decrease in load.

Like poles of the armature and field then repel each other, causing armature rotation to continue. They remain in that position for all conditions of load. Increasing the armature circuit resistance decreases motor speed.

The external resistance in series with the interople is decreased or eliminated as the motor comes up to normal speed and full voltage is applied across the armature. See the editorial for more windinvs If both are reversed, rotation will continue in the original direction. The interpole windings are connected in series with the armature windings, and therefore their correction ampere-turns increase or decrease in the same proportion as do the distorting ampere-turns of the armature.

Only outside of coils cut flux inefficient. The DC motor is reversed by reversing the direction of the current in the armature. As the load varies, the interpole flux varies, and commutation is automatically corrected as the load changes.