Page 64 - 1SBC104119C0202_MainCatalog_R contactors

Slip-ring motor control with rheostats
FOR contactors

Application
Three kinds of contactors are used to control three-phase slip-ring motors: the stator contactor, the acceleration contactor(s),
and the rotor short-circuit contactor.

Example of a three-stroke starter (star (Y) connection diagram)

Stator Rotor short-circuit Acceleration
contactor contactor contactor

R2 R1

M
3

5

The starting resistances should be star (Y) or V connected acc. to the following wiring diagrams. Contactors have to be se-
lected accordingly.

V

Stator contactor
The standard R contactor selection is based on the motor rated current acc. to the AC-2 utilization category, as well as on the
rated operational voltage and the on-load factor.

Acceleration contactor and rotor short-circuit contactor
FOR contactor selection is based on the contactor rated operational current Ie acc. to the AC-1 utilization category.

At the time of slip-ring motor starting and as soon as the motor nominal speed is reached, these contactors are used for the
short-circuiting of the rotor current limitation starting resistances (e.g. vapour-liquid rheostats).
These contactors are derived from the standard R contactors and are available in 2, 3, 4 or 6-pole versions acc. to the appli-
cable connection diagram required (Y, V).
They can control rotor currents up to 3800 A and rotor voltages up to 4200 V (with increased insulation) acc. to the
IEC 60947-4-1 standard requirements. For rotor voltages ≥ 4200 V, please consult us.
Although the breaking of the rotor circuit is normally carried out in "off-load" conditions, the contactors are equipped with blow-
out devices and can occasionally break "on-load".
Ordering details, dimensions : please consult us.

The LOR couplers may be used for applications where equipment is breaking in "Off-load" conditions only.

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