In KW control mode the engine load output is the vital factor,speed is controlled for safety purpose.
That is the engine output load is maintained with a reference load.while the engine speed is maintained within safe region.
KW control mode is used in power plants.
Tuesday, May 22, 2012
What is Resistance thermometer or resistance temperature detectors (RTDs)
Resistance thermometer or resistance temperature detectors (RTDs) is a temperature sensor to measure temperature by the property of changing resistance of the metal used in RTD's.
The RTD is made of pure metal,whose resistance change property with temperature is linear.Different resistance and corresponding temperature data is documented to use RTD as a thermometer.
Generally platinum is used as the metal in RTD's.
The RTD is made of pure metal,whose resistance change property with temperature is linear.Different resistance and corresponding temperature data is documented to use RTD as a thermometer.
Generally platinum is used as the metal in RTD's.
What is Thermistor and difference with RTD
Thermistor=Thermal+resistor -the naming of thermistor.
Difference between Thermistor and RTD:
- As construction material only ceramic or polymer is used in thermistor,where RTD is made of pure metal.
- As temperature response RTD's are useful over larger temperature range and thermistor for -93 to 130c.
Monday, May 21, 2012
Principle and theory of motor operation
The discovery that led to the invention of the electric motor was simply this:
A current carrying conductor will experience a force when placed in a magnetic field. The conductor can be any metal—iron, copper, aluminum, and so on.
The direction of the force is perpendicular to both the magnetic field and the current .
A demonstration of this principle is easy to perform with a strong magnet, flashlight battery, and a wire and is highly recommended! Place the wire between the magnet poles and alternately connect and disconnect the wire from the battery. Each time you complete the circuit, you should feel a little tug on the wire.
The magnitude of the force on the wire can be calculated from the following equation:
F = IBL sin θ
where
F = force on the conductor (in Newtons)
I = current through the conductor (in amperes)
B = magnetic flux density (in gauss)
L = length of the wire (in meters)
θ = angle between the magnetic field and current
A current carrying conductor will experience a force when placed in a magnetic field. The conductor can be any metal—iron, copper, aluminum, and so on.
The direction of the force is perpendicular to both the magnetic field and the current .
A demonstration of this principle is easy to perform with a strong magnet, flashlight battery, and a wire and is highly recommended! Place the wire between the magnet poles and alternately connect and disconnect the wire from the battery. Each time you complete the circuit, you should feel a little tug on the wire.
The magnitude of the force on the wire can be calculated from the following equation:
F = IBL sin θ
where
F = force on the conductor (in Newtons)
I = current through the conductor (in amperes)
B = magnetic flux density (in gauss)
L = length of the wire (in meters)
θ = angle between the magnetic field and current
Advantage of AC motor over DC motor
AC motors have some advantages over DC motors:
AC motors tend to be smaller, more reliable, and less expensive. However, they generally run at a fixed speed that is determined by the line frequency.
DC motors have speed-control capability, which means that speed, torque, and even direction of rotation can be changed at any time to meet new conditions. Also, smaller DC motors commonly operate at lower voltages (for example, a 12-V disk drive motor), which makes them easier to interface with control electronics.
AC motors tend to be smaller, more reliable, and less expensive. However, they generally run at a fixed speed that is determined by the line frequency.
DC motors have speed-control capability, which means that speed, torque, and even direction of rotation can be changed at any time to meet new conditions. Also, smaller DC motors commonly operate at lower voltages (for example, a 12-V disk drive motor), which makes them easier to interface with control electronics.
What is ac and dc motor
Motors are classified as either DC or AC, depending on the type of power they use.
What is an actuator
An indispensable component of the control system is the actuator. The actuator is the
first system component to actually move, converting electrical energy into mechanical
motion. The most common type of actuator is the electric motor.
Subscribe to:
Posts (Atom)