# DC Shunt Motor

Jan 22, 2012
700

#### davenn

Moderator
Sep 5, 2009
14,011
can you post the diagram here

I have to register to see that link

Dave

#### vick5821

Jan 22, 2012
700
can you post the diagram here

I have to register to see that link

Dave

Here you go

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#### duke37

Jan 9, 2011
5,364
The shunt winding produces a magnetic field.
The armature is the rotating part.

There is no difference between a motor or generator in this configuration.
If the armature is rotated in the field, it will produce a voltage (back EMF). If this voltage is below the applied voltage, the motor takes current. If this voltage is at the applied voltage, there will be no current.

If there is no torque and no friction (some hopes!), then the speed will rise till the two voltages match and the armature current will be zero. There will of course need to be a shunt, field current.

#### vick5821

Jan 22, 2012
700
If there is no armature current, how the armature develop the voltage and rotate ? Hehe

#### duke37

Jan 9, 2011
5,364
A very good point. It will never happen because there will be friction to slow the armature down as I pointed out.

The only thing perfect in this world is me !

#### Merlin3189

Aug 4, 2011
250
If there is no armature current, how the armature develop the voltage and rotate ? Hehe
Because there is a current in the field winding producing a magnetic field. A coil rotating a a magnetic field generates an emf. At the ideal free-running speed this will exactly equal the applied Voltage, so no current flows.
Though, as has been said, this never really happens, so there will be some current to generate the torque to overcome the losses.

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