Product Description

Siemens 3RB3133-4UW1 Electronic Overload Relay – 12.5–50 A, Class 5E–30E

The Siemens 3RB3133-4UW1 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable protection of three-phase motors in industrial automation and motor-control systems. It provides an adjustable current range of 12.5 to 50 A and selectable trip classes 5E, 10E, 20E and 30E. Siemens specifies this model for Size S2 stand-alone installation, with a straight-through transformer in the main circuit and screw terminals in the auxiliary circuit.

The relay provides electronic overload protection together with phase-failure and phase-asymmetry protection, while internal ground-fault detection can be activated when required. The 3RB31 family also includes manual/automatic reset, integrated electrical remote reset, switch-position indication, TEST functionality and self-monitoring.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3133-4UW1 belongs to the Siemens SIRIUS 3RB electronic overload relay family, designed to protect motors against excessive current and other abnormal operating conditions.

Its electronic measurement and microprocessor-based evaluation provide configurable protection characteristics for different motor applications.

Typical applications include:

• Industrial motor control

• Pumps

• Fans and blowers

• Compressors

• Conveyors

• Machine tools

• Production machinery

• Process equipment

• Industrial automation

• OEM control panels

Adjustable 12.5–50 A Current Range

The 3RB3133-4UW1 provides an adjustable current-setting range of 12.5 to 50 A. This allows the relay to be configured according to the rated current of the protected motor.

The current setting should be selected according to the motor nameplate current and the requirements of the complete motor-protection system.

Selectable Class 5E–30E

The relay offers four selectable trip classes:

• Class 5E

• Class 10E

• Class 20E

• Class 30E

Siemens identifies these trip classes as adjustable features of the 3RB31 electronic overload relay range.

The selectable class allows the relay to be matched to different motor starting characteristics and operating requirements.

Electronic Overload Protection

The main function of the 3RB3133-4UW1 is protection against motor overload.

The relay electronically monitors motor current and responds when the measured operating condition exceeds the configured overload characteristics.

This helps protect motors against conditions such as:

• Prolonged overcurrent

• Excessive mechanical loading

• Motor overheating caused by overload

• Abnormal operating conditions

• Incorrectly matched starting characteristics

Correct current and trip-class settings are important for reliable protection and to avoid unnecessary tripping.

Phase-Failure and Asymmetry Protection

The Siemens 3RB31 family provides phase-failure and phase-asymmetry protection in addition to overload protection.

These functions are important for three-phase motors because phase abnormalities can cause unbalanced current and additional motor heating.

The 3RB3133-4UW1 therefore provides broader motor protection than an overload-only relay.

Internal Ground-Fault Detection

The 3RB31 family includes activatable internal ground-fault detection.

This function can provide additional protection against certain ground-fault conditions without requiring a separate external detection device in suitable applications.

The complete electrical protection scheme should always be designed according to the installation requirements.

Manual, Automatic and Remote Reset

The relay supports flexible reset arrangements. The 3RB31 family provides:

• Manual RESET

• Automatic RESET

• Integrated electrical remote RESET

These options allow the relay to be incorporated into different machine-control strategies.

Manual reset can be useful where operator intervention is required after a fault, while automatic or remote reset can be used in appropriately designed automated systems.

TEST Function and Self-Monitoring

The 3RB3133-4UW1 benefits from the TEST function and self-monitoring provided by the 3RB31 family.

These functions can assist during:

• Commissioning

• Troubleshooting

• Preventive maintenance

• Functional checks

• Control-panel servicing

The switch-position indicator also provides a visual indication of the relay state.

1 NO + 1 NC Auxiliary Contacts

The Siemens 3RB31 family provides 1 normally open (NO) and 1 normally closed (NC) auxiliary contact.

These contacts can be incorporated into motor-control and automation circuits for:

• Contactor control

• Trip indication

• PLC feedback

• Alarm signalling

• Interlocking

• Motor fault monitoring

This allows the overload relay to communicate its operating condition to the associated control system.

Stand-Alone Installation

The 3RB3133-4UW1 is designed for stand-alone installation. Siemens specifies a straight-through transformer in the main circuit and an auxiliary circuit with screw terminals.

This configuration allows the overload relay to be installed separately from a contactor and integrated into a customized motor-control-panel layout.

Screw-Terminal Auxiliary Connection

The auxiliary circuit uses screw terminals, providing a conventional connection method for industrial electrical panels.

This makes the relay convenient for panel builders and maintenance teams working with standard control-circuit wiring.

Size S2 Design

The 3RB3133-4UW1 is a Size S2 overload relay. Siemens identifies S2 as both the overload-relay size and the compatible contactor size for this model.

Its stand-alone format is suitable for:

• Motor-control cabinets

• Automation panels

• Machine-control systems

• OEM equipment

• Industrial motor starters

Industrial Motor-Control Applications

The 3RB3133-4UW1 can be applied to a variety of industrial motors.

Pumps

It can protect pump motors against overload, phase failure and asymmetry.

Fans and Blowers

The selectable trip class can be matched to the motor's starting characteristics.

Compressors

Electronic overload monitoring can help protect compressor motors against excessive current.

Conveyors

The relay can protect conveyor motors against excessive mechanical loading and phase abnormalities.

Machine Tools

It can be integrated into motor-control panels for industrial machinery.

Process Automation

The combination of electronic protection, reset options and auxiliary signalling makes it suitable for automated process equipment.

Suitable for OEMs and Panel Builders

The 3RB3133-4UW1 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 12.5–50 A adjustable current, Class 5E–30E selection, phase-failure and asymmetry protection, internal ground-fault detection and stand-alone installation makes it a versatile motor-protection solution.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3133-4UW1

• Microprocessor-based electronic overload protection

• 12.5–50 A adjustable current range

• Class 5E, 10E, 20E and 30E adjustable

• Stand-alone installation

• Size S2

• Straight-through transformer in main circuit

• Screw terminals for auxiliary circuit

• Overload protection

• Phase-failure protection

• Asymmetry protection

• Activatable internal ground-fault detection

• 1 NO + 1 NC auxiliary contacts

• Manual and automatic RESET

• Integrated electrical remote RESET

• TEST function

• Self-monitoring

• Switch-position indication

Benefits

• Microprocessor-based protection: Provides electronic evaluation for configurable motor protection.

• 12.5–50 A range: Covers a broad range of compatible motor currents.

• Class 5E–30E selection: Allows protection characteristics to be matched to motor starting requirements.

• Phase protection: Helps detect phase failure and asymmetry.

• Ground-fault detection: Adds an additional protection function when activated.

• Flexible reset: Supports manual, automatic and remote reset strategies.

• Diagnostic functions: TEST and self-monitoring support commissioning and maintenance.

• Auxiliary signalling: 1 NO + 1 NC contacts provide control and fault-feedback signals.

• Stand-alone installation: Provides flexibility for customized motor-control panel layouts.

• S2 design: Suitable for compatible SIRIUS motor-control arrangements.

Why Choose Siemens 3RB3133-4UW1?

The Siemens 3RB3133-4UW1 is a flexible electronic overload relay for motor protection in the 12.5–50 A range.

Its Class 5E, 10E, 20E and 30E selectable trip characteristics allow the device to be adapted to different motor starting conditions. The relay also combines overload protection with phase-failure and asymmetry protection, plus activatable internal ground-fault detection.

With manual/automatic/remote reset, TEST functionality, self-monitoring and 1 NO + 1 NC auxiliary contacts, it provides a comprehensive protection and monitoring solution for industrial motor-control systems.

Delivery Across India

SB Smart supplies Siemens industrial electrical and automation products across Faridabad, Gurgaon/Gurugram, Delhi NCR, Haryana, Noida, Punjab, Mumbai and major cities across India.

Major delivery locations include:

• Faridabad

• Gurgaon/Gurugram

• Delhi

• Delhi NCR

• Noida

• Greater Noida

• Haryana

• Punjab

• Mumbai

• Pune

• Ahmedabad

• Bengaluru

• Hyderabad

• Chennai

• Kolkata

• Jaipur

• Chandigarh

• Lucknow

• Indore

• Surat

• Vadodara

• Nagpur

• Coimbatore

• And other major cities across India

Frequently Asked Questions

1. What is Siemens 3RB3133-4UW1?

It is a Siemens SIRIUS 3RB3 electronic overload relay for motor protection with a 12.5–50 A adjustable current range and Class 5E–30E selectable trip classes.

2. What is the current setting range?

The adjustable current range is 12.5–50 A.

3. Which trip classes are available?

The relay supports Class 5E, 10E, 20E and 30E.

4. Does it provide phase-failure protection?

Yes. The 3RB31 family provides phase-failure and asymmetry protection in addition to overload protection.

5. Does it have ground-fault detection?

Yes. It provides activatable internal ground-fault detection.

6. How many auxiliary contacts does it have?

The 3RB31 family provides 1 NO + 1 NC auxiliary contacts.

7. What reset options are available?

The relay supports manual, automatic and integrated electrical remote RESET.

8. Is it designed for stand-alone installation?

Yes. Siemens specifies the 3RB3133-4UW1 for stand-alone installation with a straight-through transformer in the main circuit.

9. What type of auxiliary terminals does it use?

The auxiliary circuit uses screw terminals.

10. Where can I buy Siemens 3RB3133-4UW1 in India?

You can explore the Siemens industrial electrical and automation product range at SB Smart for electronic overload relays, motor-protection devices, contactors and related control components.