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What is the principle operation wound rotor induction motor?
Considering a split phase single phase motor: The basic motor has a run winding uses 2 poles (or some equivalent), so the motor is activated by the single phase at 180 degree times. This needs a spin to get it started. The direction is according to the direction of the starting spin. It is an induction motor, meaning the rotor has shorting bars. The stator field is connectd to the supply, and induces the required magnetic field in the rotor by transformer action, as for other induction motors. The starting circuit has the purpose of getting the motor to spin up to sufficient speed for the run winding to take over. The rotation needs some sort of flywheel (inertial) action to carry it through the periods of zero magnetic reaction. It might use a rotor with a commutator for starting, with a centrifugal device that shorts the rotor once the speed is sufficient, so it converts to an induction motor. This method is not used much nowadays. It can have high starting torque for use with compressors for example. A common approach is to have a second field winding for starting, with poles at 90 degrees to the run winding, so there are four (or equivalent) poles. This is a two phase motor, with a separate field winding for each phase. It can be used as a 2 phase motor with the phases separated by 90 degrees. The second phase is derived from the supply using a capacitor or inductor to cause the current to lead or lag by approximately 90 degrees. The inductor type might use the different inductance of the two windings to get some current separation, and so the starting torque might be lower as this is less than 90 degrees. These were popular because capacitors were expensive. The capacitor type has a capacitor in series with the start winding, and is the most likely type nowadays. Once the rotor is up to speed the start winding can be disconnected by a centrifugal or current operated switch. Some motors run with both windings continuously connected. Another principle now out of favour because of efficiency issues is used on small motors like fans. It is called a shaded pole motor. Here a special shading pole, part of each stator field pole, is fitted with a shorting winding which causes the field to shift as it builds up on each half cycle, so there is a flick in the correct rotational direction. This has low starting torque.
What is the difference between convergent divergent nozzle and venturi tube?
In case of venturi meter, at the diverging section mach number is less than 1. however in diverging section of a nozzle mach number is greater than 1.
What is a pulley system using pulleys to increase mechanical advantages?
A pulley system is a set of wheels and ropes designed to lift heavy loads with less effort. By arranging multiple pulleys in a block-and-tackle configuration, the system increases mechanical advantage, allowing a user to lift a weight by applying a smaller force over a longer distance. This setup reduces the effort needed, making it easier to move heavy objects vertically. The more pulleys used, the greater the mechanical advantage, but this also requires pulling the rope a greater length.
Can any pulley have a efficiency over 100?
No. A perfectly frictionless machine could have an efficiency of 100%. Anything less perfect must have can efficiency less than 100%.
Would a screw with more or less threads make work easier?
It is easier. The question is not complete enough to be answered. The word EASIER needs to be further defined. so the question should read: What is easier to [add information here]; more screw threads or less screw threads?
Does a starting winding has more or less turns than a running winding?
Starting winding has more resistance and less induction than main winding, this means has smaller diameter and less turns.
Which winding has the higher resistance start or run in single phase motors?
start winding is thicker with less number of winding whereas run winding is less thicker than start winding but with more number of winding. As we know inductance depends upon numbers of turns of winding so run winding will have more inductance.
Why armature winding resistance is less than field winding resistance?
An 'armature winding' is the rotor winding, and the 'field winding' is the stator winding.
How you determine the starting and running winding of a capacitor start single phase motor?
I think the resistance value of starting winding is less than the running winding of the single phase motor
Why power at the secondary winding is less than the power at the primary winding?
If power were greater at secondary you would have an unlimited source of power. It is less because there are always losses in a transformer.
The greater the what the less current there is for a given voltage?
Resistance is probably the missing word. I = e/R. If R is greater, I is less.
Why has the greater electrical resistance in wet skin?
Wet things are provide less resistance to electricity
When testing a power transformer with an ohmmeter which winding should have the largest ohmic value?
The higher-voltage winding has more turns (therefore its conductor will be longer) than the lower-voltage winding and, because it will carry less current, its conductors will have a lower cross-sectional area. Consequently, the higher-voltage winding will have a higher resistance than the lower-voltage winding.
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.
In free fall the object with less air resistance falls with a greater acceleration.?
False
What is the blank the value of the the coefficient of friction the greater the resistance to sliding?
The coefficient of friction represents the resistance to sliding between two surfaces. A higher coefficient of friction indicates greater resistance to sliding, while a lower coefficient of friction indicates less resistance.
Is the amount of friction greater between rough surfaces smooth?
smooth surfaces have less friction, take an ice rink for example, the resistance on that is less than the resistance on asphalt
