Product Description

Siemens 3RB3026-2SB0 Electronic Overload Relay – 3–12 A, Class 20E

The Siemens 3RB3026-2SB0 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable motor protection in industrial automation and motor-control applications. It provides an adjustable current range of 3–12 A, a Class 20E trip characteristic, Size S0 construction and contactor mounting. The exact Siemens product data specifies screw terminals for both the main and auxiliary circuits, with manual and automatic reset.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3026-2SB0 belongs to the Siemens SIRIUS 3RB30 electronic overload relay family, developed to protect three-phase motors against overload, phase failure and asymmetry.

Its electronic design continuously monitors motor current and provides a defined Class 20E overload response. The relay is designed for S0 contactor mounting, allowing it to be integrated into compatible Siemens SIRIUS motor-starter assemblies.

Typical applications include:

• Industrial motor control

• Pumps

• Fans and blowers

• Compressors

• Conveyors

• Machine tools

• Production machinery

• Process equipment

• Industrial automation

• OEM control panels

Adjustable 3–12 A Current Range

The 3RB3026-2SB0 provides an adjustable current-setting range of 3 to 12 A. Siemens' current product data confirms this range.

This allows the overload relay to be adjusted according to the rated current of the protected motor.

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

Class 20E Trip Characteristic

The exact 3RB3026-2SB0 is a Class 20E electronic overload relay. Siemens identifies the article specifically under the 3RB30 Class 20E range.

The Class 20E characteristic provides a defined overload tripping response suitable for motors with corresponding starting requirements.

The selected trip class should be matched to the motor's starting time and actual application conditions.

Electronic Overload Protection

The primary function of the 3RB3026-2SB0 is electronic motor-overload protection.

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

This helps protect motors against:

• Prolonged overcurrent

• Excessive mechanical loading

• Motor overheating caused by overload

• Abnormal operating conditions

• Excessive starting duration

Correct adjustment of the current setting is important for reliable motor protection.

Phase-Failure and Asymmetry Protection

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

These functions are important for three-phase motors because phase loss or significant current imbalance can result in increased motor heating and operating stress.

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

1 NO + 1 NC Auxiliary Contacts

The 3RB3026-2SB0 incorporates 1 normally open (NO) and 1 normally closed (NC) auxiliary contact. Siemens specifies the NC contact for contactor disconnection and the NO contact for the “tripped” message.

These auxiliary contacts can be incorporated into:

• Contactor-control circuits

• 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 surrounding control system.

Contactor Mounting

The 3RB3026-2SB0 is designed for contactor mounting and belongs to Size S0. Siemens specifies the mounting method and dimensions as 87 mm height, 45 mm width and 84 mm depth.

This allows the relay to be integrated into a compact motor-starter assembly with a compatible SIRIUS contactor.

The exact compatible contactor should always be verified before installation.

Screw-Terminal Connections

The 3RB3026-2SB0 uses screw-type terminals for both the main current circuit and auxiliary/control circuit. Siemens also specifies a removable terminal for the auxiliary and control circuit.

This provides a familiar wiring method for industrial panel builders and maintenance teams.

Manual and Automatic Reset

The exact 3RB3026-2SB0 supports manual and automatic RESET. Siemens identifies both reset modes in its product description.

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

TEST Function and Self-Monitoring

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

These functions can support:

• Commissioning

• Functional testing

• Troubleshooting

• Preventive maintenance

• Control-panel servicing

Electrical Characteristics

The 3RB3026-2SB0 is designed for industrial motor-control applications and provides an auxiliary-contact rating appropriate for control circuits. Siemens specifies auxiliary-contact operational currents of 4 A at 24 V, 110 V, 120 V and 125 V AC-15, and 3 A at 230 V AC-15. For DC-13, the specified values include 2 A at 24 V and 0.3 A at 110 V.

For the complete application, the connected control circuit must be designed according to its actual voltage, utilization category and protection requirements.

Suitable for Small Industrial Motor Applications

The 3RB3026-2SB0 is suitable for motors within its 3–12 A adjustment range.

Pumps

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

Fans and Blowers

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

Compressors

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

Conveyors

It can protect compatible conveyor motors against excessive mechanical loading and phase-related abnormalities.

Machine Tools

Its compact S0 design is suitable for machine-control panels and motor starters.

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 3RB3026-2SB0 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 3–12 A adjustable current range, Class 20E protection, S0 contactor mounting, 1 NO + 1 NC auxiliary contacts, screw-terminal connections and flexible reset options makes it suitable for compact industrial motor-protection systems.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3026-2SB0

• Microprocessor-based electronic overload protection

• 3–12 A adjustable current range

• Class 20E

• Size S0

• Contactor mounting

• Screw terminals for main and auxiliary circuits

• Removable auxiliary/control terminal

• Overload protection

• Phase-failure protection

• Asymmetry protection

• 1 NO + 1 NC auxiliary contacts

• Manual RESET

• Automatic RESET

• TEST function

• Self-monitoring

• Switch-position indication

• Suitable for compatible SIRIUS contactor assemblies

Benefits

• 3–12 A adjustable range: Suitable for a range of low-to-medium current industrial motors.

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

• Electronic monitoring: Provides continuous motor-current evaluation.

• Phase protection: Helps protect against phase failure and 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: Supports commissioning and maintenance.

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

Why Choose Siemens 3RB3026-2SB0?

The Siemens 3RB3026-2SB0 is a compact electronic overload relay for motor protection in the 3–12 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 industrial motor starters, OEM machinery and automation panels.

The Siemens data sheet also identifies the article as a 12 A-rated device at 480 V and 600 V for three-phase AC motor applications, with compatible motor applications around 1.5–5.5 kW at 400 V, subject to the actual motor and application data.

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 3RB3026-2SB0?

It is a Siemens SIRIUS 3RB3 electronic overload relay for motor protection with a 3–12 A adjustable current range and Class 20E characteristic.

2. What is the current setting range?

The adjustable current range is 3–12 A.

3. What is the trip class?

The exact 3RB3026-2SB0 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. The NC contact is used for contactor disconnection and the NO contact for the “tripped” indication.

6. Is it contactor-mounted?

Yes. The 3RB3026-2SB0 is designed for S0 contactor mounting.

7. Does it use screw terminals?

Yes. Siemens specifies 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. Siemens specifies TEST functionality, switch-position indication and self-monitoring for the 3RB30 Class 20E range.

10. Where can I buy Siemens 3RB3026-2SB0 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.