Friends, today in this article we will learn about the types of induction wattmeters. I am going to give information about all these in a very good way. So let’s start.
Types of induction wattmeters-
(1) Core Type Induction Wattmeter
(2) Double Magnet Type Induction Wattmeter
(1) Core Type Induction Wattmeter-
The moving system in the core type induction wattmeter is an aluminum cylinder which is installed on a cross-shaped laminated core. A coil is made on this laminated core. This coil acts as a current coil. It is nailed to the bearing from the axis of the cylinder. This cylinder is placed in the gap of two polar electromagnets. The electromagnet on it acts as a pressure coil.
The driving torque (T₁) is proportional to the power and the spring control torque is proportional to the angle of rotation. Hence, the control (T) is also proportional to the power of the load. Compared to the dynamometer type wattmeter, the voltage or pressure coil (PC) of this type of wattmeter has high inductance which is suitable for operating this type of instrument.
(2) Dual magnet type induction wattmeter
The dual magnet induction wattmeter has two electromagnets, voltage or pressure magnet and current magnet or series magnet. Between which an aluminium (or copper) disc is installed as shown in the figure. A short path copper ring is installed for phase adjustment of the voltage magnet. They are damped from eddy current by damping magnet.
The current range is from 5 to 50A and voltage range is up to 750 V. The range of the instrument can be increased by using C.T. and P.T.
Errors in induction wattmeter-
Due to change in temperature, the moving element becomes resistant due to which the working torque is affected by changing the eddy current.
Due to change in frequency, the change in reactance of voltage coil affects the value of current and then the rotating torque is affected and the indicator shows the error.
Advantages of induction wattmeter-
Its scale has a spread of up to 300°.
Its stray magnetic field has no effect on it.
Damping is effective in these.
Disadvantages of induction wattmeter-
Power loss is high in these.
These work only on A.C.
Serious error can occur due to temperature change in these.
Due to high deflection in these, high stress acting on the spring can cause fatigue in the spring in a short time.
What did you learn today:-
Now you must have known the types of induction wattmeters. You must have got the answer to all these questions well.
I hope you liked the information given by me. If you have any question/suggestion in your mind, then you can tell me by commenting below. I will definitely answer your comment. If you liked this post, then you can also share it with your friends and relatives.