Solid State Speed Control Static Ward Leonard drives are being used these days because of the drawbacks of the classical method. All four in series each motor receives one quarter of the line voltage Two parallel groups of two in series each motor receives half the line voltage All four in parallel each motor receives the full line voltage This provided three Speed control of dc shunt motor speeds with minimal resistance losses.
Speed control methods of DC motor Speed control of Shunt motor 1.
When supply voltage V and armature resistance Ra are kept constant, the Speed is directly proportional to armature current Ia. They are smaller, lighter, more efficient and reliable than other singly-fed electric machines. AC line and Armature fuse supplied separately. This is applied for DC shunt motor.
A simulation example can be found here  and .
The Generator voltage can be varied by means of generator field regulator. The rapid switching wastes less energy than series resistors.
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Thus the final speed characteristic of a DC shunt motor, looks like. Field Voltage Control This method requires a variable voltage supply for the field circuit which is separated from the main power supply to which the armature is connected. Speed of the shunt DC motor also decreases when the motor is operated at lower voltage than its rated voltage, but this makes it inefficient with a tendency to become overburdened and overheat.
Although electronic thyristor controllers have replaced most small to medium Ward-Leonard systems, some very large ones thousands of horsepower remain in service. Tapped Field Control This is another method of increasing the speed by reducing the flux and it is done by lowering number of turns of field winding through which current flows.
An important feature of these chassis drives is its active bridge circuitry, which limits inrush current during AC line startup and prevents control runaway due to a shorted output transistor.
So the Voltage across armature is changed with the help of a suitable switchgear devises. The motor starts rotating as the magnetic field of the armature and shunt winding interact. Permanent-magnet motors[ edit ] Permanent-magnet types have some performance advantages over direct-current, excited, synchronous types, and have become predominant in fractional horsepower applications.
Armature speed is approximately proportional to the voltage across the armature. This can also be a problem with railway motors in the event of a loss of adhesion since, unless quickly brought under control, the motors can reach speeds far higher than they would do under normal circumstances.
This method is employed in electric traction. This shunt field rheostat moderates the shunt current and the flux. Speed control of series motor 1. Several models are offered, which provide the user a choice of input voltage and output current.In this system the armature of the DC Shunt motor is directly connected to a generator driven by a constant speed AC motor.
The field of the generator is supplied from the exciter (E). The field of shunt motor is supplied from a constant voltage exciter.
DC Shunt Motor Speed Control Methods. In this post, we will discuss about various speed control methods of dc shunt motor. The speed of the dc shunt motor is given by. The KBRG Series of DC Drives are rated for 1/8 to 5 horsepower DC, Permanent Magnet and Shunt motors.
These are full-wave regenerative controls, which allows forward and reverse torque in both speed directions. Shunt Wound DC Motor | DC Shunt Motor on 24/2/ & Updated on 28/8/ The shunt wound DC motor falls under the category of self excited DC motors, where the field windings are shunted to, or are connected in parallel to the armature winding of the motor, as its name is suggestive of/5(10).
A Ward Leonard control is usually used for controlling a shunt or compound wound DC motor, and developed as a method of providing a speed-controlled motor from an AC supply, though it is not without its advantages in DC schemes.
A shunt DC motor has a feedback mechanism that controls its speed. As the armature rotates in a magnetic field, it induces electricity. This EMF is generated in a reverse direction, thus limiting the armature current.Download