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What else can I help you with?
Define the term critical field resistance?
critical resistance is the maximum resistance beyond which the generator failed to exite. it can b found form the occ of the generator.
Define generator short circuit ratio?
Checked Stephen J. Chapman's Electric Machinery Fundamentals page 287. It says: Short Circuit Ratio (SCR) for the synchronous generator is the ratio of the field current required for the rated voltage at OPEN circuit to the field current require for the rated armature current at SHORT circuit.
Why is the field rheostat of a DC motor kept at minimum position while starting?
If you are talking about the field rheostat on a generator, once you have the correct voltage output set, it is very unlikely that it has to be touched again. If it is the generator's first start up, then it is best to set the field on the low side so as not to over excite the generator and drive the output voltage higher that what the generator's specifications are rated at. The field excitation voltage does not have to be set at the minimum position on every start up once it is set for the correct output voltage. A good example of this is a hospital standby generator, it starts up with no human intervention needed.
Why is it required to vary the field current in only one direction while performing the open circuit test on dc generator?
rectification to the negative voltage
What are stationary part of dc motor?
The stationary part of any motor or generator is termed the 'stator', and the rotating part is termed the 'rotor'.The stator comprises the main frame (chassis), the magnetic circuit, and field windings.
Define the term critical field resistance?
critical resistance is the maximum resistance beyond which the generator failed to exite. it can b found form the occ of the generator.
Is the critical resistance of shunt field less or more than the field resistance of generator?
More due to the impedance levels in the generator
How will a shunt generator behave if the field resistance is greater than the critical resistance?
the shunt generator wont be started .hehe
What happens to the generated voltage of a self excited generator if shunt field resistance is greater than the critical resistance?
it doesn't develop emf ..........
What is Critical resistance of field?
Critical field resistance is the limiting resistance, above which a field will not excite
What are probable causes for not have build up voltage in a shunt generator?
1. Field Flashing. 2. Resistance of the filed winding should be less than critical field resistance. 3. Speed of the motor should be greater than critical speed. 4. Interchange the field connections. 5. Check the commutator surface and brush.
What are the possible reasons for failing the voltage of a dc shunt generator to build up during starting?
Possible reasons for failure of voltage buildup... 1) No residual Magnetism, 2) Field connection may be in reverse manner, 3) Field resistance is greater than critical resistance, 4) Speed is less than Critical speed.
What are the condition of building up a self excited shunt generator?
self excited generator must be started without any external load attached ,an external load will continuously drain off the build up voltage and prevent the generator from reaching its proper operating voltage. also the presence of residual magnetism plays an important role And the field current resistance should be less than critic field circuit resistance
What are the causes for the fall in terminal voltage of adc shunt generator on load?
The fall in terminal voltage of an ADC shunt generator under load can be attributed to several factors. Firstly, the armature reaction causes a distortion of the magnetic field, leading to reduced effective field strength. Secondly, voltage drop due to armature resistance and field winding resistance becomes significant when the generator is loaded. Additionally, increased load current can cause saturation of the magnetic circuit, further diminishing voltage output.
Define generator short circuit ratio?
Checked Stephen J. Chapman's Electric Machinery Fundamentals page 287. It says: Short Circuit Ratio (SCR) for the synchronous generator is the ratio of the field current required for the rated voltage at OPEN circuit to the field current require for the rated armature current at SHORT circuit.
What is the purpose of SPST switch connected in the field circuit of the generator?
The purpose of an SPST (Single Pole Single Throw) switch connected in the field circuit of a generator is to control the excitation of the generator. By opening or closing the switch, the operator can enable or disable the flow of current to the field windings, which directly affects the generator's output voltage and reactive power. This allows for safe operation and maintenance, as well as the ability to adjust the generator's performance as needed. Additionally, it helps in protecting the generator from potential overloads or faults.
What is the excitation of the generator?
The rotor must have a magnetic field in order to generator voltage in stator winding. The exciter circuit generates this DC filed in the rotor.
