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
GWA 4NEB 430 0999-02 DS 01
3-37
3.3.3 3RT12 Vacuum contactors
Unlike the 3RT10 and 3RT14 air-break contactors – whose main contacts
have to work in the air and under atmospheric conditions– The switching
paths of the 3RT12 vacuum contactors are in hermetically encapsulated vac-
uum-switching tubes. They don’t produce any open arching nor any switch-
ing gases.
Therefore a minimal clearance to grounded parts is not required.
The following graphic shows sectional view of the vacuum tube:
Fig. 3-14: sectional view: Vacuum-tube
Applications The main areas of application of the 3RT12 Vacuum contactor are:
• Frequent switching (AC-3, AC-4)
• Heavy starting
•1000V
Attention
Vacuum contactors are not generally suitable for switching DC current!
Operation notes for the
switching of motors
with rated voltages
>500V
A surge suppression module (RC-element and Varistor) connected on the
load side of the contactor (T1/T2/T3) is recommended in order to dampen
overvoltages and protect the insulation of the motor winding from multiple
arching when switching off three-phase induction motors.
This module isn’t required if the motors that are being switched have insula-
tion set up for the operation with converters.
Attention
The main circuit surge suppressors are not needed in converter circuits!
They can be destroyed by voltage peaks and harmonics and lead to phase to
phase short circuits.
Moving contact
Fixed contact
Metallic bell
Ceramic insulator
Metallic shield
Metallic bellows