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Which the effect of the increase of the armature voltage on the speed of a direct-current separately excited motor in case of constant load?
Increasing the armature voltage would increase the speed. In a separately excited dc motor the speed adjusts so that the back emf generated by the armature is a little less than the supply voltage. The difference, divided by the resistance, gives the current drawn, which is also proportional to the shaft torque supplied to the load.
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What are the factors that influence the speed of the direct-current shunt motor with increasing load?
.The magnitude of the voltage and current of both the armature and shunt field coil. To decrease the speed when the load is increasing then increase the shunt field current while decreasing the armature voltage or current. To increase the speed while the load is increasing then increase the armature current while decreasing the shunt field current. The decreasing and increasing of these currents and voltages can be done by connecting a variable resistor in series or parallel with each of the armature and/or shunt field coil.
Why does voltage increase with current with separate excitation?
More current in the field coils means a stronger magnetic field for the armature to rotate in. This causes the output voltage for a generator to increase. For a motor, more magnetic field means that the supply voltage can be matched at a slower armature rotation speed, so the motor runs more slowly but can supply more torque.
How do you underspeed shunt motor?
To underspeed a shunt motor, you can reduce the armature voltage by using a variable resistor or rheostat in series with the armature circuit. This decreases the current flowing through the armature, thereby reducing the motor's speed. Additionally, you can also adjust the field current, as a decrease in field strength will increase the motor's speed, but this must be done carefully to prevent motor instability. Always ensure to monitor the motor to avoid overheating or damage.
What is a armature air gap?
The armature air gap refers to the space between the armature (the rotating part) and the stator (the stationary part) in electric machines such as motors and generators. This gap is crucial because it affects the magnetic field strength and efficiency of the machine. A smaller air gap generally leads to higher efficiency and performance, but it can also increase manufacturing complexity and costs. Managing the air gap is essential for optimal machine operation and longevity.
What are the causes of armature heating?
Armature heating in electrical machines is primarily caused by copper losses due to the resistance of the windings when current flows through them. Additional factors include iron losses from hysteresis and eddy currents in the magnetic core, which increase with frequency and magnetic flux density. Excessive load, poor ventilation, and inadequate cooling systems can further exacerbate heating. Lastly, short circuits or faults within the armature can lead to localized overheating.
What are the factors that influence the speed of the direct-current shunt motor with increasing load?
.The magnitude of the voltage and current of both the armature and shunt field coil. To decrease the speed when the load is increasing then increase the shunt field current while decreasing the armature voltage or current. To increase the speed while the load is increasing then increase the armature current while decreasing the shunt field current. The decreasing and increasing of these currents and voltages can be done by connecting a variable resistor in series or parallel with each of the armature and/or shunt field coil.
How can you increase density if mass is constant?
You can increase the density of an object with constant mass by decreasing the object's volume.
When does raising the temperature of a gas increase its preasure?
This is the Gay-Lussac law: at constant volume of a gas the temperature increase when the pressure increase.
How does the volume and pressure change in a tire after a long drive?
The volume is constant. The pressure will increase.The volume is constant. The pressure will increase.
What happens to the rate constant as activation energy increase?
The rate constant decreases.
How do you increase filtration rate under constant pressure?
increase the area of filtration
In an arithmetic sequence the constant rate of increase or decreas between successive terms is called the?
An arithmetic sequence does not have a constant rate of increase or decrease between successive terms, so it cannot be called anything!The constant increase or decrease is called the common difference.
What happens when load is removed from an operating series DC motor?
The speed will increase possibly to the point that it throws out the coils from the armature & self destructs.
Does the increase in heat result in an increase in pressure?
Yes, generally an increase in heat will result in an increase in pressure, assuming the volume remains constant. This is based on the ideal gas law, where pressure is directly proportional to temperature when volume is constant.
Why does voltage increase with current with separate excitation?
More current in the field coils means a stronger magnetic field for the armature to rotate in. This causes the output voltage for a generator to increase. For a motor, more magnetic field means that the supply voltage can be matched at a slower armature rotation speed, so the motor runs more slowly but can supply more torque.
What will increase voltage if current is increased?
a constant resistance
When are electromagnets used to increase or decrease the voltage of electric currents?
Electromagnets are never used to increase or decrease the voltage in a circuit. These magnets in conjunction with a rotating device (an armature) can create a voltage but the do not have any effect on a voltage.
