# Making a DC electric Motor - Coil Wiring

Discussion in 'Sensors and Actuators' started by Samcj9, Jan 18, 2015.

1. ### Samcj9

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Jan 18, 2015
Hi, I am currently making a DC electric motor for a high school physics assessment. I have two questions:

1. In a two coil motor, should the coil be wound in the same direction for both coils and should this be in the direction that the current is flowing?

2. Should the soft iron core inside the coils be bigger than the magnets or smaller?

Thank you very much!

2. ### duke37

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769
Jan 9, 2011
1. You can wind the coil in either direction but it must be connected to produce the correct magnetic polarity.

2.I would think that the working area should be as big as possible. The air gap should be as small as possible.

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Nov 10, 2014
4. ### Samcj9

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Jan 18, 2015
I'm still a little confused at what you mean when you say that it must be connected to produce the correct magnetic polarity. Could you expand on this a little? Thanks.

5. ### Samcj9

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Jan 18, 2015
Also, when I am winding the coil around my iron core, is it best to wind the coil fully around to create one layer and then wind on top of it creating another layer? Or is one layer of coil enough?

6. ### duke37

5,364
769
Jan 9, 2011
If you wind clockwise then you will get the opposite magnetic polarity if you wind anticlockwise but if you swap the feed over, you will be back to the original polarity. It will be easier to wind in a consistent way and then connect to give the correct magnetic polarity.

The winding should have minimal resistance so one thin layer will be inefficient. Normally the wire will fill the available space and the wire thickness and number of turns will be set to suit the current the motor will take.

7. ### Bluejets

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Oct 5, 2014
Are you winding the armature or the field coils?

8. ### Samcj9

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Jan 18, 2015
Not exactly sure what you mean. Basically, I am winding a coil around an iron core. The two coils are attached to the armature, whilst the magnets remain stationary on the ground.