Why Slipring Motor is used in Crane?
Hello friends, in which post today we will know why we use slipring motor in crane? Meaning why slipping motor is always used inside the crane? Apart from this, in this post we will talk about some more important questions related to slipring motor.
Why Slipring Motor used in Crane?
Why slippering motor is used in Crane?
The answer is in just one line that in all our cranes or lifts, we need a motor whose starting torque is very high.
Now when some people hear the word torque in their mind, there must have been confusion that what is this torque in the motor, so friends, we understand it easily.
What is Torque in Motor?
To explain better what is the torque in the motor, we are running with 2 conditions.
Case 1- Suppose you have a bicycle and no one is sitting on this cycle and now you are asked to ride this cycle, then you will easily run it by giving a pedal in the cycle.
Here you will have to apply very little force to start a long cycle.
Case 2- But now if let's say in the second example that 3-4 people are now seated behind this cycle and you are now asked to start the cycle.
So in this second case we will find it much more difficult to start the cycle.
Now why is it getting difficult to start the cycle in the second example? So this is happening because in the second case, due to the sitting of 3-4 people on the cycle, we have to exert more force to start the cycle, which means we have to apply high pressure in starting.
So friends, what we have seen in both the examples, with the help of both, you can understand torque practically. Here in the first case, we were reading the need to apply a lot of pressure to start the cycle, meaning we needed very low torque, but when it came to starting the cycle by sitting 3-4 people, in that case we needed high torque. .
So friends, exactly the same thing happens with our cranes. Whenever we talk about a crane, we know that the motor of the crane already has a lot of weight on that motor and the motor has to rotate by lifting that load.
So at this time we need a motor for the crane which can run smoothly even with high load in starting, that means we need a motor whose starting torque is very high.
Friends, till now we have learned in this topic that we need a motor in the crane, whose starting torque is very high. So now after this when we check the motor kept with us, we see that our most used motor is squirrel cage induction motor, but its starting torque is very less, why is it less then We will understand this further.
But before that you should know that after all how is the starting torque of slip ring motor more?
Why Slipring motor starting Torque is High?
The reason behind the high torque of the slip ring motor is related to the construction and working of this motor, when you ever look at the slip ring motor you will see that this motor looks almost similar to the squirrel cage induction motor. But friends there is some difference between slip ring motor and squirrel cage motor.
Difference between Slipring and Squirrel cage motor
Difference between slippering motor and squirrel cage motor?
Friends Slipring and Squirrel cage The main difference between these two motors is in their rotor itself.
When you look at the rotor of both these motors, you will see that in our slip ring motor, winding is done on the stator as well as on its rotor and after winding on the rotor, another important thing is the rotor of the slipring motor. But that is Slipring.
What is slipring and what are its uses?
Friends, you can see in the picture what the slippering looks like in the motor.
But if we talk about its use, it works like a carbon brush in a way.
You must have seen the carbon brush installed inside many motors, in the same way slipping is also applied on the rotor of the motor. With the help of this slippering, we are able to connect the rotor of the motor with the resistance box kept outside.
On the other hand, if we talk about squirrel cage motor, on the other hand, winding is done on the rotor but the structure of its rotor is quite simple.
The winding on the squirrel cage rotor is done with the help of a conductor bar, which you can see in the picture. Apart from this, there is no other winding on this rotor, due to which the squirrel cage rotor is very simple.
But friends, now let's talk about a very important question. After all, why are we connecting the winding on its rotor inside the slippering motor, bringing that rotor winding through the resistance box?
What is the function of Resistance Box in Slipring Motor?
What is the use of resistance box in slippering motor? And at the same time the whole working of this motor is very easy. For this, you just have to always remember one simple thing.
That whenever we increase the resistance of the rotor of a motor, that means, if we add a rotor with more resistance to the motor, then due to this the current value of the motor decreases and due to the decrease of this current, we have to remove the motor from the motor. Very high torque is available.
So now we have come to know that if we want to take more torque from any motor, then for that we just have to add more resistance on the rotor of that motor. After which the current of the motor will decrease and we will easily get more torque. And we do the same thing with our slip ring motor.
Inside the slip ring motor, we put a slip ring on the rotor of our motor and the wire that comes out of the slipring, we connect it to the resistance box with the help of a contactor.
After this, whenever we need more torque from the motor, at that time we add extra resistance on the rotor with the help of slippering. Due to which the current of the motor decreases and we get more torque from the motor.
So friends, till now we have known what is slipring motor, how it works and what is the difference between squirrel cage and slipring motor. But now after this we talk on one last question, can we use squirrel cage motor on crane?
Can we use Squirrel cage Motor on Crane?
The answer to this question is in simple words yes, we can use Squirrel cage motor in crane. But now after hearing this answer, most of the people will think that if we can use squirrel cage motor, then why are we using crane slip ring motor?
So friends here you should know one thing, that if we ever want to use squirrel cage motor in crane, then at that time we have to take high starting torque from squirrel cage motor. Now the question comes how can we get more torque than squirrel cage motor?
So friends, to do this you have to connect VFD with this motor. Meaning that the variable frequency drive will have to be added.
If you want to see it practically, then you can see its use inside the train.
Whenever the train is started, a lot of torque is required to run the train at that time, and we easily take this torque requirement from our squirrel cage motor. Because inside the train we are using VFD.
But when we talk about industry, there we always use slippering motor, not squirrel cage motor, in places with high torque like inside crane. Because to get more torque from the squirrel cage motor, we have to install VFD and when we look at the price of VFD Drive, it is quite expensive. So for this reason only slippering motors are used in the industry where there is a need for more torque.