Product Description

Siemens 3RB3026-2NB0 Electronic Overload Relay – 0.32–1.25 A, Class 20E

The Siemens 3RB3026-2NB0 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable protection of low-current three-phase motors against overload, phase failure and asymmetry. It provides an adjustable current range of 0.32 to 1.25 A, a Class 20E trip characteristic, Size S0 construction and contactor mounting. Siemens specifies screw terminals for both the main and auxiliary circuits and manual/automatic reset for this exact article.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3026-2NB0 belongs to the Siemens SIRIUS 3RB30 electronic overload relay family, designed for electronic motor-current monitoring and protection.

Its microprocessor-based electronic design continuously evaluates motor current and provides a defined overload response. The compact S0 contactor-mounted construction allows the relay to be integrated with compatible Siemens SIRIUS contactors in motor-starter assemblies.

Typical applications include:

• Small industrial motors

• Pumps

• Fans and blowers

• Small compressors

• Conveyors

• Machine tools

• Production machinery

• Process equipment

• Industrial automation

• OEM control panels

Adjustable 0.32–1.25 A Current Range

The 3RB3026-2NB0 provides an adjustable current-setting range of 0.32 to 1.25 A. Siemens' product data confirms this exact adjustment range.

This makes the relay 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.

Class 20E Trip Characteristic

The exact 3RB3026-2NB0 is a Class 20E electronic overload relay. Siemens identifies the article under the 3RB30 Class 20E range.

The Class 20E characteristic provides a defined overload tripping response for motors with corresponding starting requirements. The appropriate trip class should be matched to the motor starting time and application conditions.

Electronic Overload Protection

The primary function of the 3RB3026-2NB0 is electronic motor-overload protection.

The relay continuously monitors motor current and responds when the configured overload characteristic is exceeded.

This helps protect compatible motors against:

• Prolonged overcurrent

• Excessive mechanical loading

• Motor overheating caused by overload

• Abnormal operating conditions

• Extended starting duration

Correct current adjustment is essential for reliable motor protection.

Phase-Failure and Asymmetry Protection

The Siemens 3RB30 Class 20E family provides overload, phase-failure and asymmetry protection.

These functions are important for three-phase motors because phase loss or current imbalance can increase motor heating and electrical stress.

The relay therefore provides broader motor protection than overload protection alone.

1 NO + 1 NC Auxiliary Contacts

The 3RB3026-2NB0 provides 1 normally open (NO) and 1 normally closed (NC) auxiliary contact. Siemens specifies this arrangement for the 3RB30 Class 20E range.

These auxiliary contacts can be used for:

• Contactor control

• Trip indication

• PLC feedback

• Alarm signalling

• Motor fault monitoring

• Control-system interlocking

The auxiliary contacts provide a practical interface between the overload relay and the associated control system.

Contactor Mounting

The 3RB3026-2NB0 is designed for contactor mounting and belongs to Size S0. Siemens' product data specifically identifies the article as an S0 overload relay for contactor mounting.

This allows the relay to form a compact motor-starter assembly with a compatible Siemens SIRIUS contactor.

Screw-Terminal Connections

The 3RB3026-2NB0 uses screw-type terminals for both the main current circuit and auxiliary/control circuit. Siemens product documentation confirms screw connections for both circuits.

The auxiliary/control terminal is removable, supporting practical wiring, commissioning and maintenance.

Manual and Automatic Reset

The exact 3RB3026-2NB0 supports manual and automatic RESET. Siemens identifies both reset modes for this article.

Manual reset can be used when operator intervention is required following an overload trip, while automatic reset can be used where permitted by the complete machine-control design.

TEST Function and Self-Monitoring

The Siemens 3RB30 Class 20E family includes:

• TEST function

• Switch-position indication

• Self-monitoring

These functions can support commissioning, functional testing, troubleshooting and preventive maintenance.

Electrical Characteristics

The 3RB3026-2NB0 has an insulation voltage of 690 V and a 6 kV surge-voltage resistance. Siemens' datasheet specifies approximately 0.1 W total power loss at rated current in the hot operating state, or approximately 0.03 W per pole.

The device is intended for industrial motor-control applications and should be installed according to the specified electrical, wiring and environmental requirements.

Compact S0 Design

The 3RB3026-2NB0 is a compact S0-size overload relay with approximate dimensions of 87 mm height, 45 mm width and 84 mm depth.

Its compact construction is suitable for:

• Motor starters

• Automation cabinets

• Machine-control panels

• OEM electrical assemblies

• Industrial control systems

Industrial Motor-Control Applications

Small Pumps

The relay can protect compatible low-current pump motors against overload, phase failure and asymmetry.

Fans and Blowers

The Class 20E characteristic can be used for motors with corresponding starting requirements.

Small Compressors

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

Conveyors

The relay can protect compatible low-current conveyor motors against excessive mechanical loading and phase-related abnormalities.

Machine Tools

Its compact S0 construction is suitable for machine-control panels and motor-starter assemblies.

Process Automation

The relay can be integrated into automated systems for motor protection, trip signalling and contactor control.

Suitable for OEMs and Panel Builders

The 3RB3026-2NB0 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 range, Class 20E protection, S0 contactor mounting, 1 NO + 1 NC auxiliary contacts, screw terminals and manual/automatic reset makes it suitable for compact low-current motor-protection systems.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3026-2NB0

• Microprocessor-based electronic overload protection

• 0.32–1.25 A adjustable current range

• Class 20E

• Size S0

• Contactor mounting

• Screw terminals for main and auxiliary circuits

• 1 NO + 1 NC auxiliary contacts

• Overload protection

• Phase-failure protection

• Asymmetry protection

• Manual RESET

• Automatic RESET

• TEST function

• Self-monitoring

• Switch-position indication

• 690 V insulation voltage

• 6 kV surge-voltage resistance

Benefits

• 0.32–1.25 A adjustable range: Suitable for low-current industrial motors.

• Class 20E: Provides a defined overload characteristic for compatible motor-starting requirements.

• Electronic monitoring: Provides continuous motor-current evaluation.

• Phase protection: Helps protect against phase failure and current asymmetry.

• 1 NO + 1 NC contacts: Provides control, signalling and trip-feedback paths.

• Contactor mounting: Supports compact S0 motor-starter assemblies.

• Screw terminals: Provides a familiar industrial wiring method.

• Manual/automatic reset: Supports different motor-control strategies.

• TEST and self-monitoring: Support commissioning and maintenance.

• Compact S0 construction: Helps optimize control-panel space.

Why Choose Siemens 3RB3026-2NB0?

The Siemens 3RB3026-2NB0 is a compact electronic overload relay designed for motor protection in the 0.32–1.25 A range with a Class 20E trip characteristic.

Its combination of electronic overload, phase-failure and asymmetry protection, S0 contactor mounting, 1 NO + 1 NC auxiliary contacts, screw connections and manual/automatic reset makes it suitable for small industrial motor starters, OEM machinery and automation panels.

Siemens product data identifies it as an active SIRIUS 3RB3 electronic overload relay with 0.32–1.25 A adjustment, S0 contactor mounting and screw connections, making this exact article suitable for compatible low-current motor-protection applications.

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 3RB3026-2NB0?

It is a Siemens SIRIUS 3RB3 electronic overload relay for motor protection with a 0.32–1.25 A adjustable current range and Class 20E characteristic.

2. What is the current setting range?

The adjustable current range is 0.32–1.25 A.

3. What is the trip class?

The exact 3RB3026-2NB0 is Class 20E.

4. Does it provide phase-failure protection?

Yes. The Siemens 3RB30 range provides phase-failure and asymmetry protection in addition to overload protection.

5. How many auxiliary contacts does it have?

It provides 1 NO + 1 NC auxiliary contacts.

6. Is it contactor-mounted?

Yes. The 3RB3026-2NB0 is designed for S0 contactor mounting.

7. Does it use screw terminals?

Yes. It uses screw-type terminals for both the main and auxiliary circuits.

8. What reset options are available?

It supports manual and automatic RESET.

9. Does it have diagnostic functions?

Yes. The 3RB30 Class 20E range includes TEST functionality, switch-position indication and self-monitoring.

10. Where can I buy Siemens 3RB3026-2NB0 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.