the back emf increases so that high currents doesn't pass through the field windings
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.
it is kept at minimum position to produce more torque which is required for starting a motor
initial torque to overcome the friction in generator and then to keep constant speed of stator within the generator. Minimum 50NM
For a shunt dc motor the rheostat would vary from zero ohms to a value that produces the required minimum field current, but rheostats are not common with shunt motors except as a crude way of controlling the speed. Series dc motors normally use rheostats for starting, especially in trams etc. because the starting torque and current is very high. The rheostat resistance starts at a value equal to the supply voltage divided by the maximum allowable current drawn, and is reduced as the speed builds up.
If you have the Maximum clock frequency, then you can figure out the minimum clock period using this formula: 1/(minimum clock period) = (Maximum clock frequency).
the back emf increases so that high currents doesn't pass through the field windings
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.
A generator, rated at 16 MW, should be able to continuously supply a load of 16 MW. You don't need to compute its 'minimum load', because the minimum load will be zero watts! In other words, you can run the generator with no load whatsoever if you wish to waste fuel.The point is that the power supplied by a generator is determined by the load, NOT by the generator itself -so it is important that the generator is capable of supplying the maximum load applied to it. A generator's 'rated power output' simply tells us the maximum load it is capable of supplying.
It is a variable resistor. Basically, the same as when you turn up or down the heat on an electrical oven or radio.
it is kept at minimum position to produce more torque which is required for starting a motor
The extrema are the maximum and minimum values.The extrema are the maximum and minimum values.The extrema are the maximum and minimum values.The extrema are the maximum and minimum values.
The term is "resting position" (also equilibrium position).
The opposite of minimum is maximum.
Maximum:
A parabola's maximum or minimum is its vertex.
Minimum-Maximum was created in 2005-06.
A maximum or minimum is generally referred to as an extrema.