![ADVANCES IN INTERPRETING PARTIAL DISCHARGE TEST RESULTS FROM](http://s1.studyres.com/store/data/008910220_1-1648e02bdb2aaf7e6f1819255c5ce4f6-300x300.png)
1 Chapter.2 DESIGN OF DC MACHINES Details to be specified
... arcing between commutator segments increases. The arc between the segments in turn may bridge the positive and negative brushes leading to a dead short circuit of the armature or flash over. 9. Labour charges As the number of poles increases cost of labour increases as more number of poles are to be ...
... arcing between commutator segments increases. The arc between the segments in turn may bridge the positive and negative brushes leading to a dead short circuit of the armature or flash over. 9. Labour charges As the number of poles increases cost of labour increases as more number of poles are to be ...
Electric generator
... single-pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic. He also may have formulated the concept of the dynamo in 1861 (before Siemens and Wheatstone) but didn't patent it as he thought he wasn't the first to realize this.[2] ...
... single-pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic. He also may have formulated the concept of the dynamo in 1861 (before Siemens and Wheatstone) but didn't patent it as he thought he wasn't the first to realize this.[2] ...
DC Motors - UET Taxila
... When the motor is running on no load, small torque is required to overcome the friction and windage losses. Therefore, the armature current Ia is small and the back e.m.f. is nearly equal to the applied voltage. (ii) If the motor is suddenly loaded, the first effect is to cause the armature to slow ...
... When the motor is running on no load, small torque is required to overcome the friction and windage losses. Therefore, the armature current Ia is small and the back e.m.f. is nearly equal to the applied voltage. (ii) If the motor is suddenly loaded, the first effect is to cause the armature to slow ...
Experiment 2 - Rensselaer Polytechnic Institute
... as the top of the cradle remains open. Also, other materials can be added. For example, a small wire (spring) can be used to hold the coil in the cradle as long as it is not connected electrically to the cradle. Final performance testing must be done with either the battery or the DC power supply an ...
... as the top of the cradle remains open. Also, other materials can be added. For example, a small wire (spring) can be used to hold the coil in the cradle as long as it is not connected electrically to the cradle. Final performance testing must be done with either the battery or the DC power supply an ...
Herbert Stemmler
... CSIs) are the most commonly used basic circuits for large drives. They are simple and easy to build for high-power applications. With regard to their characteristics they, however, are inferior: When implemented at the mains side they draw a 120° square wave current, which lags the voltage by 0° to ...
... CSIs) are the most commonly used basic circuits for large drives. They are simple and easy to build for high-power applications. With regard to their characteristics they, however, are inferior: When implemented at the mains side they draw a 120° square wave current, which lags the voltage by 0° to ...
EE 448
... required. When running at no-load, the motor is always noisier than at full-load because only under full-load does it run as a true two-phase machine. If the proper value of capacitance is chosen, the power factor can be close to 100% under full load conditions. However, the starting torque is quite ...
... required. When running at no-load, the motor is always noisier than at full-load because only under full-load does it run as a true two-phase machine. If the proper value of capacitance is chosen, the power factor can be close to 100% under full load conditions. However, the starting torque is quite ...
NCEA Level 3 Physics (90523) 2012 Assessment Schedule
... coils of the motor changes, inducing an EMF across the ends of the coil. • The EMF is proportional to the rate of change of flux so the faster the motor spins the greater the EMF. • The induced EMF will oppose the EMF from the battery, so it will limit the current in the coil. (This limits the amoun ...
... coils of the motor changes, inducing an EMF across the ends of the coil. • The EMF is proportional to the rate of change of flux so the faster the motor spins the greater the EMF. • The induced EMF will oppose the EMF from the battery, so it will limit the current in the coil. (This limits the amoun ...
View - The IJST
... neutral point can vary from zero to 300 V. The allowable common mode voltage for a comparator is typically a few volts, i.e. 5 V. Obviously, the voltage divider will reduce the signal sensitivity at low speed, especially at start-up where it is needed most .On the other hand, the required low pass f ...
... neutral point can vary from zero to 300 V. The allowable common mode voltage for a comparator is typically a few volts, i.e. 5 V. Obviously, the voltage divider will reduce the signal sensitivity at low speed, especially at start-up where it is needed most .On the other hand, the required low pass f ...
Typical Current Transformer
... the design of the current transformer is such as to provide a maximum secondary current corresponding to a full-scale deflection on the ammeter. In most current transformers an approximate inverse turns ratio exists between the two currents in the primary and secondary windings. This is why calibrat ...
... the design of the current transformer is such as to provide a maximum secondary current corresponding to a full-scale deflection on the ammeter. In most current transformers an approximate inverse turns ratio exists between the two currents in the primary and secondary windings. This is why calibrat ...
from archives-ouvertes.fr - Supelec
... Furthermore, the typical advantages of DTC are not sufficient. EV induction motor drive has also to possess high efficiency in order to extend the running distance per battery charge. Therefore, DTC should be associated to a lossminimization strategy to maximize the drive efficiency. Indeed, EV moto ...
... Furthermore, the typical advantages of DTC are not sufficient. EV induction motor drive has also to possess high efficiency in order to extend the running distance per battery charge. Therefore, DTC should be associated to a lossminimization strategy to maximize the drive efficiency. Indeed, EV moto ...
UNIT – VI UNIT-6: SPECIAL MACHINES Explain the constructional
... losses because of its highly resistive nature. Hence a centrifugal switch (SC) is used to disconnect the auxiliary winding from the circuit when the motor picks up speed. The torquespeed characteristic of this motor is shown in fig, which also shows the speed ‘N0’ at which the centrifugal switch ope ...
... losses because of its highly resistive nature. Hence a centrifugal switch (SC) is used to disconnect the auxiliary winding from the circuit when the motor picks up speed. The torquespeed characteristic of this motor is shown in fig, which also shows the speed ‘N0’ at which the centrifugal switch ope ...
Electrical Installations Level 3 - Pearson Schools and FE Colleges
... The e.m.f. produces circulatory currents within the rotor bars, which in turn result in the production of a magnetic field around the bars. This leads to the distortion of the magnetic field as shown in Figure 6.08. The interaction of these two magnetic fields results in a force being applied to the ...
... The e.m.f. produces circulatory currents within the rotor bars, which in turn result in the production of a magnetic field around the bars. This leads to the distortion of the magnetic field as shown in Figure 6.08. The interaction of these two magnetic fields results in a force being applied to the ...
sns college of engineering
... familiar with this fact that the current flowing through the capacitor leads the voltage. So, in capacitor start inductor motor and capacitor start capacitor run induction motor we are using two winding, the main winding and the starting winding. With starting winding we connect a capacitor so the c ...
... familiar with this fact that the current flowing through the capacitor leads the voltage. So, in capacitor start inductor motor and capacitor start capacitor run induction motor we are using two winding, the main winding and the starting winding. With starting winding we connect a capacitor so the c ...
Commutator (electric)
![](https://commons.wikimedia.org/wiki/Special:FilePath/Universal_motor_commutator.jpg?width=300)
A commutator is the moving part of a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. The commutator is one component of a motor; there are also two or more stationary electrical contacts called ""brushes"" made of a soft conductor like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature are connected to the commutator segments. Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (torque) is produced. In a generator the commutator picks off the current generated in the windings, reversing the direction of the current with each half turn, serving as a mechanical rectifier to convert the alternating current from the windings to unidirectional direct current in the external load circuit. The first direct current commutator-type machine, the dynamo, was built by Hippolyte Pixii in 1832, based on a suggestion by André-Marie Ampère. Commutators are relatively inefficient, and also require periodic maintenance such as brush replacement. Therefore, commutated machines are declining in use, being replaced by alternating current (AC) machines, and in recent years by brushless DC motors which use semiconductor switches.