Product Description

Siemens 3RB3113-4NB0 Electronic Overload Relay – 0.32–1.25 A, Class 5E–30E

The Siemens 3RB3113-4NB0 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable protection of motors against overload, phase failure and phase asymmetry. It provides an adjustable current-setting range of 0.32 to 1.25 A, selectable trip classes 5E, 10E, 20E and 30E, and S00 contactor mounting. Siemens specifies screw connections for the main and auxiliary circuits, along with internal ground-fault detection and flexible reset functions.

The compact relay is suitable for small-current motor applications where accurate electronic overload protection and adjustable trip characteristics are required.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3113-4NB0 belongs to the Siemens SIRIUS 3RB31 electronic overload relay family. Its microprocessor-based design electronically evaluates motor current and provides configurable protection characteristics.

Compared with conventional thermal overload relays, the 3RB31 series provides additional monitoring and protection functions, making it suitable for modern industrial motor-control systems.

Typical applications include:

• Small pumps

• Fans and blowers

• Small compressors

• Conveyors

• Machine tools

• Industrial machinery

• Process equipment

• Automation panels

• OEM motor starters

• Control cabinets

Adjustable 0.32–1.25 A Current Range

The 3RB3113-4NB0 provides an adjustable current range of 0.32 to 1.25 A. Siemens lists this exact setting range for the article.

This range makes the device suitable for motors with relatively low rated currents.

The current setting should be adjusted according to the protected motor's nameplate current and the requirements of the complete motor-protection system.

Selectable Class 5E–30E

The relay supports selectable trip classes:

• Class 5E

• Class 10E

• Class 20E

• Class 30E

Siemens identifies these as selectable trip classes for the 3RB31 electronic overload relay family.

The adjustable trip class allows protection to be matched to different motor starting times and operating requirements.

Electronic Overload Protection

The primary function of the 3RB3113-4NB0 is electronic protection against motor overload.

The relay continuously monitors the motor current and responds when the current exceeds the configured inverse-time overload characteristic.

This helps protect compatible motors against conditions such as:

• Prolonged overcurrent

• Excessive mechanical loading

• Motor overheating caused by overload

• Abnormal operating conditions

• Incorrectly selected motor-protection settings

Correct current and trip-class adjustment is essential for effective protection.

Phase-Failure and Asymmetry Protection

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

These functions are particularly relevant for three-phase motors, where a missing or unbalanced phase can result in increased current and thermal stress.

Internal Ground-Fault Detection

The 3RB3113-4NB0 includes activatable internal ground-fault detection. Siemens identifies internal ground-fault detection as part of the 3RB31 protection functions.

This provides an additional monitoring function for suitable motor-protection applications.

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

Manual and Automatic Reset

The 3RB31 series supports manual and automatic reset, along with an integrated electrical remote RESET function.

This allows the overload relay to be incorporated into different control strategies.

Manual reset is useful when operator intervention is required after a fault, while automatic or remote resetting can be applied where the control-system design permits it.

TEST Function and Self-Monitoring

Siemens specifies the 3RB31 family with a TEST function, switch-position indication and self-monitoring.

These features support:

• Commissioning

• Functional testing

• Troubleshooting

• Preventive maintenance

• Control-panel servicing

1 NO + 1 NC Auxiliary Contacts

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

These contacts can be used for:

• Contactor control

• Trip indication

• PLC feedback

• Alarm signalling

• Control-system interlocking

• Motor fault monitoring

The auxiliary contacts allow the overload relay's operating or trip status to be incorporated into the surrounding control system.

S00 Contactor Mounting

The 3RB3113-4NB0 is designed for mounting on S00 contactors. Siemens identifies the product in the S00 range as a device for mounting on contactors.

This enables a compact motor-starter configuration when used with a compatible Siemens SIRIUS contactor.

Screw-Terminal Connections

The 3RB3113-4NB0 uses screw connections for the main and auxiliary circuits. Siemens documentation identifies screw-terminal versions in the S00 range, with the 4NB0 article belonging to this configuration.

This provides a conventional wiring method for industrial control-panel installation and maintenance.

690 V Insulation Voltage

The product datasheet specifies an insulation voltage of 690 V and 6 kV surge-voltage resistance.

These ratings should be considered together with the actual motor-control system, protective coordination and installation conditions.

Compact S00 Design

The 3RB3113-4NB0 is a compact S00-size electronic overload relay. The available datasheet specifies approximately 79 mm height, 45 mm width and 73 mm depth, making it suitable for compact motor-control assemblies.

Industrial Motor-Control Applications

Small Pumps

The relay can protect suitable low-current pump motors against overload and phase-related abnormalities.

Fans and Blowers

Its selectable trip classes allow the protection characteristic to be matched to the motor starting requirements.

Small Compressors

Electronic overload protection can help protect compressor motors from excessive current.

Conveyors

The relay can be integrated into low-current conveyor motor-control systems.

Machine Tools

Its compact S00 format is suitable for machine-control panels and small motor starters.

Process Automation

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

Suitable for OEMs and Panel Builders

The 3RB3113-4NB0 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 0.32–1.25 A adjustable current, Class 5E–30E selection, phase-failure and asymmetry protection, internal ground-fault detection, flexible reset functions and S00 contactor mounting makes it suitable for low-current industrial motor-protection applications.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3113-4NB0

• Microprocessor-based electronic overload protection

• 0.32–1.25 A adjustable current range

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

• S00 size

• Contactor mounting

• Screw connections

• 690 V insulation voltage

• 6 kV surge-voltage resistance

• Overload protection

• Phase-failure protection

• Phase-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 motor-current monitoring and configurable protection.

• 0.32–1.25 A range: Suitable for low-current motor applications.

• Class 5E–30E selection: Allows the trip characteristic 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 assist commissioning and maintenance.

• Auxiliary signalling: 1 NO + 1 NC contacts provide control and trip-feedback functions.

• Contactor mounting: Supports compact SIRIUS motor-starter assemblies.

• Screw connections: Provides a familiar industrial wiring solution.

Why Choose Siemens 3RB3113-4NB0?

The Siemens 3RB3113-4NB0 is a compact electronic overload relay designed specifically for motors requiring protection within the 0.32–1.25 A setting range.

Its Class 5E, 10E, 20E and 30E adjustable trip characteristics provide flexibility for different motor starting conditions. The relay also combines overload, phase-failure and asymmetry protection with activatable internal ground-fault detection, flexible reset functions, TEST capability and self-monitoring.

With S00 contactor mounting, 1 NO + 1 NC auxiliary contacts and screw connections, it provides a compact motor-protection solution for OEM machines, control panels and industrial automation 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 3RB3113-4NB0?

It is a Siemens SIRIUS 3RB3 microprocessor-based electronic overload relay with a 0.32–1.25 A adjustable current range and Class 5E–30E selectable trip classes.

2. What is the current setting range?

The adjustable current range is 0.32–1.25 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 and automatic RESET, and the series also provides integrated electrical remote RESET.

8. Is it contactor-mounted?

Yes. The 3RB3113-4NB0 is designed for S00 contactor mounting.

9. What type of terminals are used?

The 4NB0 version uses screw connections for the main and auxiliary circuits.

10. Where can I buy Siemens 3RB3113-4NB0 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.