Connecting a three-phase motor according to a star and delta circuit

The current-carrying windings of the electric motor are routed into a distribution box. The terminals of the windings form two parallel rows, each marked with the letter C and numbers from 1 to 6. This is done in order to mark the beginning and end of all three windings.
The connections are quite complicated. This can be found out using a simple tester. Calling the terminals of the windings, we will find that only two of them are connected along a large diagonal. The rest are connected along small diagonals.
Ringing the windings is necessary when using an old electric motor; in a new one, such work is unlikely to be required. After checking, the motor can be connected either in a star or delta configuration.
Note: a combined star-delta circuit is also used to connect electric motors with a power of more than 5 kW.

Turning on the windings with a star

The "star" circuit involves connecting the ends of the windings at one point, which is called the neutral, and applying supply voltage to the beginning of each of the windings.The "triangle" circuit provides for a series connection of windings.

For a star connection, two jumpers (three jumpers are included with the electric motor) are installed on the terminals in the same row. Then the jumpers are fixed with nuts. Wires from a three-phase network are connected to the three terminals of the second row.

Switching on the motor windings with a triangle

The “triangle” circuit is used to connect the electric motor to a single-phase 220 V network. Three jumpers connect the terminals located opposite each other. On one side, the jumpers are fixed with nuts, on the opposite side we connect wires from the network to two terminals, and to the third - a wire from the working capacitor (the capacitance must be calculated correctly).

Tip: when purchasing an electric motor, it is advisable to check the number of wires in the junction box. The presence of 6 wires to the contacts indicates the possibility of connecting the motor according to any scheme. Three wires mean that the winding contacts are already connected in a star configuration and connection to a single-phase network in a delta configuration is impossible. In this case, you will have to open the engine and remove the missing ends. This will be quite difficult to do.
Each connection scheme has its own characteristics. The electric motor, when connected in a star configuration, operates smoothly, but cannot develop the power that is indicated in the product data sheet.
The "triangle" circuit allows the electric motor to achieve maximum power, but to reduce the value of the resulting starting currents, it is necessary to use a starting rheostat.

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