 Hello everyone welcome to this session I am Priyanka Bansore and today we are going to study about working of TACO generator. These are the learning outcomes of this video lecture at the end of this session students will be able to explain construction principle and operation of TACO generator and explain types of TACO generator. These are the contents we will be covering in this session. Before moving towards pause this video for few seconds and you have to think and write the difference. Do you know the difference between TACO meter and TACO generator? Let us see the difference between TACO meter and TACO generator. So first TACO meter consist of TACO generator and TACO generator is usually referred as permanent magnet DC brush generator. Then next a TACO meter is just a display for human readings and a TACO generator can be a part of control loop. Then next a TACO meter is an instrument that measures and displays rotational speed. But TACO generator is an electric generator that generates a voltage that is accurately proportional to the speed of the shaft. Now we will see in detail about TACO generator. The word TACO generator comes from the Greek word TACO. So TACO generator consist of two words that is TACO plus generator. In Greek TACO means speed and the generator means an instrument which generate power. So here the figure shows the TACO generator and shaft. TACO generator is a device which is used for measuring the speed of shaft and converting this speed into a voltage so that it can be measured. So voltage is measured through this voltmeter. Common voltage signal used with TACO generators is 0 to 10 volts. We see the types of TACO generator. There are two types of TACO generator. So first AC TACO generator and second DC TACO generator. First we see about AC TACO generator. The AC TACO generator is a small brushless alternator with a rotating multiple permanent magnet. In AC TACO generator the armature is provided with an AC winding either single phase or three phase winding and the output voltage is measured by a voltmeter although the varying frequency will affect the accuracy of this instrument. Now we see the construction and working of AC TACO generator. So here the AC TACO generator consists of permanent magnet then rectifier for converting AC output into the DC then smoothing circuit moving coil voltmeter and the rotor where the speed is to be measured. When the rotor is stationary no AMF is induced in the output winding and primary winding excited by an AC input voltage. The induced voltage in secondary is 0 due to relative position of two windings being placed at 90 degrees to each other. Then as the rotor rotates a voltage is induced in the secondary winding whose magnitude is proportional to the rotor speed and then EMF is induced in the quadrature coil and this EMF is directly proportional to the rotor speed. So here the equation is VT is equal to kT phi of T where VT is the voltage and phi of T is the rotor speed and kT is nothing but it is the TACO generator constant and is in phase with applied voltage to the reference coil. We see about DC TACO generator. A DC TACO generator is a small DC generator which has to generate electrical voltage corresponding to the speed of rotating machine. Then the produced voltage is dynamically induced EMF. Dynamically induced EMF means what? When the conductor is in motion and the field is in stationary and EMF is induced in the conductor and this type of EMF is called dynamically induced EMF. The requirement of this EMF is to establish necessary flux in the field and also system of conductors is required so that a relative motion between the flux and the conductor create rate of change of flux linkage and generate the DC voltage. So the field system may be in the form of electromagnet or permanent magnet and it is stationary part of the DC TACO generator. So now we see the construction and working of DC TACO generator. So here the DC TACO generator consists of permanent magnet, moving coil voltmeter and shaft for speed measuring. Same as the AC TACO generator but here no need of rectifier because already output is in DC form. Then the series resistance is used to limit the current under output short circuit condition. Then the polarity of output voltage indicates the direction of rotation. Then the commutator collects the current from the armature conductors and converts internally induced AC EMF into the DC EMF. Then brushes are used to collect current from commutator and make it available to external circuitry of the DC TACO generator. So this is the construction about the DC TACO generator actually DC TACO generator is based on the principle of Faraday's law of electromagnetic induction. According to the law when a conductor move in a magnetic field it cut the magnetic lines of force due to which an EMF is induced in the conductor. We know that the magnitude of induced EMF depends upon the rate of change of magnetic flux linkage with the conductor. Now we see the working principle of DC TACO generator. So first the armature of DC TACO generator is kept in a permanent magnetic field and the armature of TACO generator is coupled to the machine whose speed is to be measured. When the shaft of the machine revolves the armature of the TACO generator also revolves in the magnetic field producing EMF which is proportional to the product of flux and speed to be measured. As the field of permanent magnet is fixed the EMF generated is proportional to the speed directly. And this generator EMF is measured using moving coil rule meter. We see the difference between AC and the DC TACO generator. So first difference is in AC TACO generator speed is measured only in one direction and in DC TACO generator speed is measured in both direction. Then next in AC TACO generator rectifier is needed because here we have to convert AC output into the DC but in DC TACO generator already output is in DC form. So no need of rectifier. Then next here ripples are reduced in AC TACO generator and small ripples are appearing at the output in DC TACO generator. And then the last one maintenance is difficult in AC TACO generator and maintenance is easy in DC TACO generator. So these are the some points between the AC TACO generator and the DC TACO generator. Now we see the advantages of TACO generator. First it is simple in construction and design then it is not expensive. It has a linear relationship between output and the rotational speed. It requires less maintenance and temperature compensation is also simple. It is advantages of TACO generator. So first it is limited to low speed and tachometers are hard to calibrate. These are the applications of TACO generator. So first is majoring rotating speed of disk or shaft. This is the main application of TACO generator. Then it is used in automobile speedometer. It is used in industries and rail for controlling motor and speed respectively. These are the some references of this video lecture. Thank you.