Product Description

Siemens 3RB3026-2QB0 Electronic Overload Relay – 6–25 A, Class 20E

The Siemens 3RB3026-2QB0 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable motor protection against overload, phase failure and phase asymmetry. It provides an adjustable current range of 6 to 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.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3026-2QB0 belongs to the Siemens SIRIUS 3RB30 electronic overload relay family, developed for electronic protection of three-phase motors.

The relay continuously evaluates motor current and provides inverse-time overload protection. Its compact S0 contactor-mounted design allows integration with compatible Siemens SIRIUS contactors in 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 6–25 A Current Range

The 3RB3026-2QB0 provides an adjustable current-response range of 6 to 25 A, with a 25 A thermal current. Siemens' current datasheet confirms these ratings for the exact article.

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

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

Class 20E Trip Characteristic

The exact 3RB3026-2QB0 is a Class 20E electronic overload relay. Siemens explicitly specifies Class 20E for this article.

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

Electronic Overload Protection

The primary function of the 3RB3026-2QB0 is electronic motor-overload protection.

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

This helps protect motors against:

• Prolonged overcurrent

• Excessive mechanical loading

• Motor overheating caused by overload

• Abnormal operating conditions

• Extended starting duration

Correct current adjustment is important for dependable motor protection.

Phase-Failure and Asymmetry Protection

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

Phase failure and current imbalance can increase motor heating and electrical stress. Electronic monitoring therefore provides broader protection for three-phase motors than overload protection alone.

1 NO + 1 NC Auxiliary Contacts

The 3RB3026-2QB0 provides 1 normally open (NO) and 1 normally closed (NC) auxiliary contact. The relay's auxiliary contacts can be used for contactor control, trip indication, PLC feedback and signalling.

Typical uses include:

• Contactor-control circuits

• Trip indication

• PLC feedback

• Alarm signalling

• Motor fault monitoring

• Control-system interlocking

Contactor Mounting

The 3RB3026-2QB0 is designed for contactor mounting and belongs to Size S0. Siemens specifies a compact 87 mm height, 45 mm width and 84 mm depth.

This arrangement allows the overload relay to be integrated directly into a compatible SIRIUS motor-starter assembly.

Screw-Terminal Connections

The 3RB3026-2QB0 uses screw-type terminals for both the main current circuit and auxiliary/control circuit. The auxiliary/control terminal is removable.

This provides a conventional wiring method for electrical panel builders and maintenance teams.

Manual and Automatic Reset

The exact 3RB3026-2QB0 supports manual and automatic RESET. Siemens specifies a typical recovery time of approximately 3 minutes after an overload trip with automatic reset, while manual and remote reset conditions can have a typical 0-minute recovery time.

The reset mode should be selected according to the machine and control-system requirements.

TEST Function and Self-Monitoring

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

These functions can assist with:

• Commissioning

• Functional testing

• Troubleshooting

• Preventive maintenance

• Control-panel servicing

Electrical Characteristics

The 3RB3026-2QB0 has a 690 V rated operating voltage, 50–60 Hz operating frequency, 690 V insulation voltage and 6 kV surge-voltage resistance. Siemens also specifies approximately 1.2 W total power loss at rated current in the hot operating state.

The operating ambient temperature range is -25 °C to +60 °C, with installation altitude up to 2,000 m under the specified conditions.

Industrial Motor-Control Applications

Pumps

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

Fans and Blowers

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

Compressors

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

Conveyors

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

Machine Tools

Its compact S0 design is suitable for motor-control assemblies used in machinery.

Process Automation

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

Suitable for OEMs and Panel Builders

The 3RB3026-2QB0 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 6–25 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 industrial motor-protection systems.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3026-2QB0

• Microprocessor-based electronic overload protection

• 6–25 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

• 690 V insulation voltage

• 6 kV surge-voltage resistance

Benefits

• 6–25 A adjustable range: Suitable for motors within the specified current range.

• 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: Support commissioning and maintenance.

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

Why Choose Siemens 3RB3026-2QB0?

The Siemens 3RB3026-2QB0 is a compact electronic overload relay for motor protection in the 6–25 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 industrial motor starters, OEM machinery and automation panels.

The exact Siemens datasheet confirms the 6–25 A current range, Class 20E, S0 size, contactor mounting and screw-terminal configuration, making this model a practical choice for compatible motor-control 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 3RB3026-2QB0?

It is a Siemens SIRIUS 3RB3 electronic overload relay for motor protection with a 6–25 A adjustable current range and Class 20E characteristic.

2. What is the current setting range?

The adjustable current range is 6–25 A.

3. What is the trip class?

The exact 3RB3026-2QB0 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 3RB3026-2QB0 is designed for S0 contactor mounting.

7. Does it use screw terminals?

Yes. Siemens specifies screw-type terminals for 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 3RB3026-2QB0 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.