Why 230VAC is written with Delta-connection on Motors nameplates

[Engr. Laeeq]

Hello everyone, I want to know that why 230VAC is written with Delta connection & 400VAC is written with Y-connection on every motor's nameplate. I can't find any answer to this.:-(

 

[kak111]

Look these three pictures...








Under IEC standards, all motors are described in terms of their operating and design characteristics using
a motor nameplate attached to body of the motor’s housing.
Nameplates which can display the following specific pieces of information:

1. Manufacturer name and manufacturer-specific ordering code.
This code will typically contain information about frame size and mounting arrangement.
2. Rated volts - The voltage at which the motor is designed to operates and give optimum performance.
3. Full load amps –.used to facilitate cable sizing, starter selection and motor protection.
4. Rated frequency in Hertz, and rated full load speed in revs/minute at that frequency.
5. Rated temp rise or insulation class – Industry standard specification of the thermal tolerance of the motor insulation.
6. Rated power (kW).
7. Electrical connection and associated operating parameters –
i.e. three phase motors can be connected in a ‘star’ (Υ) or ‘delta’ (Δ) configuration.
In a star configuration the current flowing from the supply is reduced as is the torque.
8. Power factor for the motor.
9. Efficiency class – IEC nameplates quote EFF ratings at full load.
It is a measure of how well the motor converts electrical energy to mechanical power.

 

[FvM]

The diagram shows the two connection options but possibly doesn't answer your question about the meaning of the typeplate marking.

A motor with 230/400V marking as you refer to has to be connected in Y circuit to a standard 400 V power supply (left side of the diagram). The circuit on the right side circuit applies to a motor specified with 400/690 V. The latter can be also operated with a wye/delta starter.