OMEC MOTORS
OMT1 & OMT2 Mounting & Maintenance Instructions
Page 7
5.2.
Circuit
Normally our motors are provided with a terminal box with six connections, to which six
leads from the winding are connected either in a delta connection or in a star connection
by means of connection links.
Usually two voltages are indicated on the nameplate of these motors, which means that
the motor can be connected to a circuit having one of these voltages.
If the main voltage is corresponding with the lowest indicated voltage, the winding has to
be connected in delta connection (see figure 1); if it is corresponding with the highest
indicated voltage, the winding has to be connected in star connection (see figure 2).
A motor with e.g. 230/400V on its rating– plate is suited to be switched on directly, on a
circuit with a voltage of 230V between phases with the winding connected in a delta
connection, or on a circuit with a voltage of 400V with the winding connected in a star
connection.
But if the motor is switched on with a star– delta starter the motor is only suited for a
main voltage on the rating-plate, this is the delta voltage. In this case, the connection
strips on the terminal box have to be removed when the motor is connected; the star and
delta connection will be made successively in the starter during the run up. If only one
voltage is indicated on the rating– plate together with the delta sign, the motor can be
switched on directly at the indicated voltage or with a star/delta start.
Pole change motors (for two or more speeds) are connected according to a diagram sent
together with the motor.