What is a Motor Winding: Types and Its Calculation, Part Winding Start, Power Engineering, Machines,Motor Winding Connection, What are "motor windings".
We need to discuss motor connection and starting terminology for three phase motors in order to understand the wye-delta motors.The most economical way to start a three phase squirrel cage is with a full voltage starter.The starting method is referred to as:
A motor with only three leads is suitable for full voltage starting.The internal connections of the motor coil are known as wye.This type of motor does not require a connection diagram because the electrician simply connects the three motor leads to the starter terminals.The figure is for the connection schematic.
Most distributors like to stock motors that can be used with power supplies.Many motors are rated for dual voltage.The 9 lead, dual voltage motor is the most common domestic motor.The ration is 1:2.The coils are connected in parallel for both 230 and 460 volt operations.
There are many foreign countries with power supplies of 220 and 380 volts.The relationship between a wye connected motor and a delta connected one is shown in the following schematic.The type of motor has six leads.
The motor is connected to the power supply and can be used for wye-delta or star-Delta.The motor is connected to the starter in the starting mode.Since we only apply 220 volts, the motor will only develop 33% Torque and draw only 1/3 of the normal starting current.The starter changes the motor coil from wye to delta, which is the full voltage running connection.
One of the "S" contactors is shown dotted in the figure since some starter manufacturers use only two instead of three.A 3/50/ 220/380 motor could also be called a wye-delta start.
Sometimes a customer doesn't know what they want.A request for a three phase motor may state that the power supply is 50hertz.This usually means three phase and single phase.
If the request is for a 3/50/ 220/380 motor, the customer may want to use the motor on a 220 volt power supply with a wye-delta starter.Depending on the country, he may sell the motors to different countries.
We get requests for 3/50/380/660 motor.We can't give a motor in size ratings that are suitable for wye-start, delta-run.The reason we can't provide such a motor is because our random wound insulation system is only approved for 600 volts, plus 10%.There are only two countries in the world that have a 660 watt power supply.Some power plants use a 660volt distribution for their in-plant equipment.
There are some distributors who like to sell dual voltage wye-start, delta run motors.This type of motor requires twelve leads and is connected parallel wye-delta for low and high voltages.The figure is below.
Part winding.The method used only a portion of the motor winding, increasing the impedance seen by the power system.It must not be left on the start connection for more than 2 to 3 seconds.The motor is not expected to accelerate on the start connection.