Separately Excited dc Motor

[mufcforever7]

what is a separately excited dc motor? Izzit using a normal dc motor to connect become separately or how?

I have searched in the internet but i dun quite understand it.

Please guide me on this.

Thank you very much!

 

[crutschow]

I believe you are referring to a shunt-wound dc motor which uses a separate dc voltage to excite the field windings. In a series-wound motor the armature and field windings are in series so there is no separate excitation for the field.

 

[cr0sh]

I believe you are referring to a shunt-wound dc motor which uses a separate dc voltage to excite the field windings. In a series-wound motor the armature and field windings are in series so there is no separate excitation for the field.

Shunt-wound vs series-wound refer to how the stator (field) and rotor coils are connected; in parallel for the shunt-wound motor, in series for a series-wound motor. A shunt-wound motor can have a separately excited field winding (for speed control, for instance), but it doesn't necessarily have to be this way (both could be driven from the same supply in parallel).

 

[mufcforever7]

Hi crutchow and crOsh,

im doing a project titled speed control of separately-excited dc motor. After i do some research on the separately-excited dc motor i don't really understand how to connect the motor.

Are we just using a normal 12V or 24V dc motor?

Please guide me.

Thank you!

 

[kinarfi]

I'm probably making some errors here, you'll need to do own research, As I remember from days gone by of working on a dragline, many dc generators were driven by a couple thousand horse sync motor. The stator and the rotor had separate controllable voltages. the more current, excitation, through the stator created more torque, and slower, for a constant rotor voltage. Once spinning, if stator is disconnected, the rotor would run away, going so fast it would fly apart. The variable stator/field is like weaker or strong permanent magnets and the rotor voltage does the same as in a PM motor.

 

[crutschow]

im doing a project titled speed control of separately-excited dc motor. After i do some research on the separately-excited dc motor i don't really understand how to connect the motor.

Are we just using a normal 12V or 24V dc motor?

You need a DC motor with a separate connections for the field windings. You connect a variable voltage supply to the field to vary field current and thus the speed of the DC motor. And contrary to intuition, the higher the field current, the slower the motor runs.

Typical 12V or 24V dc motors do not have those separate field connections available.