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Why is the field rheostat of a DC motor kept at minimum position while starting?
Wiki User
∙ 11y ago
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.
Wiki User
∙ 9y ago
Wiki User
∙ 11y agoAt starting, to reduce the starting current, the armature resistance is high. To produce better starting torque, we require the value of field resistance to be minimum.
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Why motor rheostat kept minimum position generator rheostat maximum position?
the back emf increases so that high currents doesn't pass through the field windings
Why field rheostat of dc shunt motor kept in minimum position?
it is kept at minimum position to produce more torque which is required for starting a motor
What will happen if field rheostat of dc shunt motor is kept at maximum position while starting?
First remember this rheostat is connected in series with the armature to increase the total resistance to limit the starting current, thus achieving max starting torque from the motor
How do you select field rheostat range for dc motor?
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.
Why the armature voltage E changes when the field rheostat is varied?
This depends on how the motor and wiring. You'll need to provide more information. Series / compound / shunt / differential / self or separately excited / is the rheostat in parallel or series to the field / is the rheostat on the shunt field or series field (if compound)
Why motor rheostat kept minimum position generator rheostat maximum position?
the back emf increases so that high currents doesn't pass through the field windings
Why field rheostat of dc shunt motor kept in minimum position?
it is kept at minimum position to produce more torque which is required for starting a motor
When the rheostat position is changed from minimum position to maximum position in motors what will happens?
the back emf increases so that high currents doesn't pass through the field windings
What will happen if field rheostat of dc shunt motor is kept at maximum position while starting?
First remember this rheostat is connected in series with the armature to increase the total resistance to limit the starting current, thus achieving max starting torque from the motor
How do you select field rheostat range for dc motor?
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.
Why the armature voltage E changes when the field rheostat is varied?
This depends on how the motor and wiring. You'll need to provide more information. Series / compound / shunt / differential / self or separately excited / is the rheostat in parallel or series to the field / is the rheostat on the shunt field or series field (if compound)
Why the generator field rheostat kept at maximum position?
There is nothing to limit current until opposing magnetic fields build up at generator operating speed-windings will overheat and burn.
What are the values of armature and field rheostat to be maintained during starting of a d.c motor?
you want full field while starting 0 Ohms and maximum series on armature then bring the armature resistance to zero as it approaches running speed its a good idea to run with armature at 0 ohms armature will use the same amount of power as the resistor If you want to run at more than base speed you can now weaken the field
Can a starting pitcher complete 1 inning then move to another position on the field for 1 inning and then return to the pitching position the following inning?
Yes, the pitcher and any other player may move to any position on the field and back to his original position, or any other position at any time during the game.
What is the minimum GPA of East field College?
The minimum GPA of east field Collage is 3.2.
What does entry level position mean?
To discus about different things ---------------- It usually means they want someone just out of college or someone making a career change and they are starting at the bottom. Entry level means you'll get less pay as well because you they look for applicatants with no to little working experince in that paticular field.
What are some good paying jobs one can get without going to college to long?
The nursing field only requires a minimum of two years for a RN position.
