The motor should run on Star connection or Delta connection?
motor-star-connection-and-delta-connection-difference
You may have seen many times that we use the motor running from our three-phase supply by connecting it in two ways of methods, so today we have a difference between these two methods and when to run the motor in star connection and when in delta connection. The motor should run on delta connection or star connection?
How is the star and delta connection of the motor done?
We all know that there are 6 terminals in the connection box of a three-phase motor.
When we have to drive the motor in star connections.
Star-connected-motor
Here we short the three terminals of one side (W2, U2, V2) and give our electrical supply to the remaining three points. As shown in the above image.
Delta-connected-motor
And when we do delta connection. So in this, we short the two points opposite to each other in front of the motor terminal box. As you can see in the above photo and then we give electrical supply to these three terminals. In this way, it becomes a delta connection.
The main reason for connecting the motor to delta or star connection is the efficiency of that motor.
For example, if the efficiency of our motor is decreasing, then we run the motor in star connection to correct the efficiency of that motor.
What is efficiency in Motor?
The meaning of efficiency is quite easy to understand. For example, we have a motor. Now that the motor is working as much as its capacity or not, we know from its efficiency only. Meaning if our motor is 6HP - 6 Horsepower = 4,474.19 Watts, then it is actually giving as much power as 6HP or not.
Motor Efficiency
What does the efficiency of a motor mean?
Electric motor efficiency is the ratio between power output and power input.
If the efficiency of the motor is good, then it means that the motor is giving full power and if the efficiency of the motor is poor means less, then it is not giving its full power.
How to Calculate Motor Efficiency? How to know motor efficiency?
Finding the efficiency of any motor is a very difficult task.
What is the motor efficiency formula?
If ever you want to calculate the efficiency of a motor, you have to divide the output power by the input power of the motor.
But now we are talking about star and delta connections. So in this, we just have to keep in mind that if we have added less load on our motor, then due to this the motor efficiency decreases.
How to know if the motor is on load or offload?
For this, we just have to look at the rated current of the motor. We get this current easily on the nameplate of the motor.
Motor Nameplate rated current
Now we have to find out whether our motor is running on the same load as its rated current or not.
Example- Like on motor nameplate is written 15 amperes rated current, then if this motor is taking 12-13 ampere current then it is correct which means motor on load. But if the motor is drawing less than 40% of its rated current, then this motor is connected on no load, which means the load on the motor is connected less.
What to do if the motor is not loaded?
Having a no-load condition means that we have added very little load to the motor. If our load is going to remain the same in future also. Then we would consider it right to replace this motor and put a low power motor in this place.
But if after a few days the load on the motor can increase back, then at this time we will run the motor by connecting it to the star connection for a few days.
How to check our motor load or unload condition?
All we have to remember is that our motor is drawing 40% or less of its rated current in a Delta connection. So we have to connect this motor in star connection so that the efficiency of our motor can be increased.
Can we use the electric motor in the star connection?
So if it is an electric motor with 230Volt windings and does not require special launches - probably because it drives a small load of equipment then running on a star would be fine.
Can we use Delta motor on Star connection?
The answer to your question is no. One rotation point for each star is connected within the center. The neutral connection is internal, hence it cannot be opened to make a delta connection.
Should the motor engine run on Star Connection or Delta Connection?
Once the engine has achieved a certain rotation speed the launcher will switch to a delta-connected configuration that will allow the engine to produce full power. If the engine is left connected to the Star it will operate at the right speed but will have 1/3 of less power than when the Delta was connected.
Why are the motors connected in Delta connection?
The delta connection to the motor is used because it provides additional power and initial torque. But the current start is high. A star connection is used where you may want to slow down the car start to speed up and connect to the delta in normal operating mode.
Is the delta connection neutral?
In the Delta connection, there is no neutral point. The end of each coil is connected at the start of another coil which means the opposite terminals of the coils are connected together.
Why are High Voltage motors connected to a star connection?
In a high-powered car, the current is usually small, and the level of engine installation is required to be high, so the installation of a star with a star connection is better and more economical.
Why use Star and Delta Connection in motors?
Star / Delta connection launchers are probably the most frequently reduced power starters. They are used in an attempt to reduce the initial power applied to the motor for the first time as a way to reduce interference and interruptions in the supply of electricity.
What are the benefits of Delta Connection?
The advantage of Delta connectivity is high reliability. If one of the three main winding fails, the second one will still produce full voltage at all three phases. All that is needed is for the remaining two sections to be able to carry the load.
Does a 3 phase motor require neutrality?
A three-phase engine does not require neutrality as it is an equal load in three phases. Whether the engine is connected to a star or a delta configuration, each phase pulls the same current power, and the total current power at any given time equals the negative current in the other phases.
When using a star-connected engine?
The star connection is usually used in HT motors, those motors are used where low initial torque is required. Since the torque is equal to the square of the voltage, so the star connection is used because in a star connection the voltage across each winding is small.
Which draws the current star connection or Delta connection?
This means that the star engine has a low starting current, but will slow down, bringing less torque as well as power. The delta wound engine motor flows heavily into the corresponding connected windows, so it consumes most of the current start-up and has high speed, torque, and power output.
Why does Delta not need neutrality?
In a balanced system, where all the currents and their strengths are the same, the total phasor for all line currents is 0A. That is why there is no need for a neutral cord in a balanced system.
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