User Guide
Table Of Contents
- 3 3RT1 contactors/ 3RH1 control relays
- 3.1 Specifications/regulations/approvals
- 3.2 Device description
- 3.3 Application and areas of use
- 3.3.1 3RT10 contactors with 3 main contacts for switching motors
- 3.3.2 3RT14 contactors with 3 main contacts for switching resistive loads (AC-1)
- 3.3.3 3RT12 Vacuum contactors
- 3.3.4 3RT13 and 3RT15 contactors with 4 main contacts
- 3.3.5 3RT16 capacitor contactors
- 3.3.6 Contactors with an extended operating range
- 3.3.7 3RH1 control relays
- 3.3.8 3RT10 contactor relays for switching motors (interface) and 3RH11 control relays for switching auxiliary circuits
- 3.3.9 3RA13 Contactor combinations for reversing
- 3.3.10 3RT14 Wye-delta combinations
3RT1 contactors/3RH1 control relays
SIRIUS System Manual
3-66 GWA 4NEB 430 0999-02 DS 01
Frame size S2
Fig. 3-31: Wye-delta combination (frame size S2)
Field of application The wye-delta combination is used to start three-phase induction motors
which require a low load torque during startup.
Starting current ratio Wye-delta starting can only be used when the motor normally operates in
delta mode, starts with no load, or if the load torque during the wye startup
is small and does not increase rapidly.
In the wye stage, the motors can be loaded with approximately 50 %
(torque class KL16) and 30 % (KL10) of its rated torque.
The starting torque is reduced to approximately 1/3 of the value at direct
power-up.
The starting current is approximately 2 to 2.7 times the rated current for the
motor.
Switch-over Switching from the wye to the delta stage can only be carried out once the
motor has completed startup to the rated speed.
The required switch-over time delay and interlock is included in the contac-
tor combination.
Important
Motors that require an early switch-over are not suitable for wye-delta start-
ing.
Overload protection The fully assembled combinations are not equipped with overload protec-
tion. Overload relay (3RU11) and tripping devices for thermistor motor pro-
tection must be ordered separately.
The overload relays can be attached to the contactor directly or set up sepa-
rately. The overload relay is set to 0.58 times the set current I
e
. See
Chapter 4 on overload relays for further information.
Timing relay, at the side