Understanding Delta & Star Load Connections

In summary: You would have to use a three phase transformer to step down the voltage to single phase, and then use a switch to turn the single phase power on and off when you want to use it.In summary, you can't just wire your single phase load in parallel with the three phase power system. You would need a three phase transformer to step down the voltage to single phase, and then use a switch to turn the single phase power on and off when you want to use it.
  • #1
amaresh92
163
0
why do we require delta and star load connection ?
thanks.
 
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  • #2
Perhaps you should first tell us what type of alternative load connections you are proposing.
 
  • #3
amaresh92 said:
why do we require delta and star load connection ?
thanks.
Those are the two basic ways that three phase is connected with. Note that a delta load can usually be connected with a star (wye) three phase power system by just not using the neutral.

Is there more to you question that I didn't really understand?
 
  • #4
Skaperen said:
Those are the two basic ways that three phase is connected with. Note that a delta load can usually be connected with a star (wye) three phase power system by just not using the neutral.

Is there more to you question that I didn't really understand?

why we can't connect it as simple parallel and series as in case of single phase ac?
thanks
 
  • #5
amaresh92 said:
why we can't connect it as simple parallel and series as in case of single phase ac?
thanks

You can connect in series in certain cases. If you have 3 transformers, each with their primaries powered by separate pases in a normal three phase system, you can wire the secondaries in series. You do have to perform some vector arithmetic (or simply plot it geometrically) to see what you would get in various configurations. With two of them in series (assuming each is 240 volts), you can get a total of 240 volts in one case, or about 415.692 volts in the other case. Three of them in series can be configured for a number of voltages from zero to 480.

Paralleling the secondaries would result in very high circulating currents because of the phase angle difference. But one configuration of three secondaries can form a closed delta with minimal circulating currents (at least at the primary frequency).

If you have a simple single phase load, such as one heating element, and want to power it from all phases to keep things in balance ... sorry, you cannot do that.
 

What is the difference between delta and star load connections?

The main difference between delta and star load connections is the way the three phases are connected. In a delta connection, all three phases are connected in a triangle, while in a star connection, the three phases are connected in a star shape. This difference affects the voltage and current distribution in the circuit.

How do delta and star load connections affect voltage and current?

In a delta connection, the voltage across each load is equal to the line voltage, while in a star connection, the voltage across each load is equal to the line voltage divided by the square root of 3. In terms of current, in a delta connection, the line current is equal to the load current, while in a star connection, the line current is equal to the load current multiplied by the square root of 3.

What are the advantages of using a delta connection?

One advantage of using a delta connection is that it requires fewer wires compared to a star connection, making it more cost-effective. Additionally, the delta connection can handle higher loads and is more suitable for three-phase motors.

When should I use a star connection instead of a delta connection?

A star connection is more suitable when the loads are balanced and do not vary greatly. It also provides a neutral point, which can be used for grounding and balancing the voltage. Star connections are commonly used for lighting and small appliances.

Can I convert a delta connection to a star connection?

Yes, it is possible to convert a delta connection to a star connection by adding a neutral wire and connecting it to the center point of the delta. However, it is important to consider the voltage and current ratings of the loads before making any changes to the connection.

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