How can a DC motor be made to operate at its base speed? By connecting full voltage to both the armature and shunt field. … The resistance of the shunt field produces heat, which prevents the formation of moisture inside the motor.
How is a DC motor made to run above its base speed?
How can a DC motor be made to operate above its base speed? When full voltage is applied to the armature and reduced voltage is applied to the shunt field the motor operates above base speed.
How is the speed of a DC motor controlled below base speed?
Speeds above the motor base (nameplate) speed are obtained by weakening the motor shunt field with a rheostat or electronically. Speeds below the motor base speed are obtained by weakening the generator field. This, in turn, lowers the generator voltage supplying the DC motor armature.
What are the factors that control the speed of a DC motor?
Thus, there are three general methods of speed control of D.C. Motors.
- Resistance variation in the armature circuit: This method is called armature resistance control or Rheostat control.
- Variation of field flux Ф This method is called field flux control.
- Variation of the applied voltage.
What are the disadvantages of DC motor?
Disadvantages of DC motors
- High initial cost.
- Increased operation and maintenance cost due to the presence of commutator and brush gear.
- Cannot operate in explosive and hazard conditions due to sparking occur at brush (risk in commutation failure)
Which DC motor is preferred for constant speed?
Que 28. Which D.C motor is preferred for machine tools? Explanation: DC shunt motor is a constant speed motor tool machine such as lathe machine requires being run at a constant speed.
How can I reduce the speed of a 12v DC motor?
A couple of things you can do:
- Use gears to change ratio of speed, which is what you’re going to do. …
- Use a stepper motor, which are commonly used for high-torque, low RPM applications.
- Find some sort of PWM control circuit to slow it down, although you probably won’t be able to get it down to 5-10RPM.
Why is it necessary to control the speed of a DC motor?
DC Motors plays an important role in energy conversion process. It is a machine which converts electrical energy into mechanical energy. In mechanical system, speed varies with number of task so speed control is necessary to do mechanical work in a proper way. It makes motor to operate easily.