Duplex Lap Winding of DC Motor Armature

Duplex lap winding is two wound layers in parallel instead of one wound layer.

At the same applied voltage it increases the total current thru the windings.

"keeping the winding design same"? If you mean the same wire size and windings, you can change to duplex, but it is not the same and will not improve anything if the armature is already near saturation. Your question indicates that you do not know enough to re-design the armature windings, so unless you have it re-designed, you should best leave them the same.

What are you trying to accomplish?

Duplex windings had two circuits in parallel , simplex only one. The commutator bars and width of the brushes must match the intended armature connection.

Simplex, Duplex, Triplex, etc will depend of the current handled and the armature-commutator-brush rigging design.

Attempting change of the original circuits will require proper redesign of all the involved machine elements including the equalizing system.

As recommended above, if you have only basic knowledge of DC machines, do not attempt any re-design which could turn into a big catastrophe.

As suggested. it would be catastropic to change from Simplex to Duplex Winding.

But I would like to know - why duplex winding is used?

Duplex lap winding is one in which the end lead of a coil is connected two bars away form the beginning lead.

There is no advantage other than the fact it is done when it is desired to run the motor at a lower voltage, the brush area now must contact at least two commutator bars

Yes U can if only u intend to use the motor in a voltage lower than the previous.

Dickson. Abuja, Nigeria

Pls. note Lap, Duplex Lap, Triplex Lap are only ways or partern of connecting armature wires on commutators bars. Normal Lap Winding is for the intended voltage, Duplex Lap is for a lower voltage than the voltage of the normal Lap and Triplex Lap has to do with further reducing the voltage.

In Normal Lap winding, the brush must span at least more than one slot.

In Douplex Lap winding, the brush must span at least more than two slots.

In Triplex Lap winding, the brush must span at least more than three slots.

Please note ur previous ratings and look for a good rewinding book.

Dickson. Abuja, Nigeria.