Product Description

Siemens 3RB3036-1UB0 Electronic Overload Relay – 12.5–50 A, Class 10E

The Siemens 3RB3036-1UB0 is a microprocessor-based electronic overload relay from the Siemens SIRIUS 3RB3 series, designed for reliable protection of industrial motors against overload, phase failure and phase asymmetry. It provides an adjustable current range of 12.5 to 50 A, a Class 10E trip characteristic, Size S2 construction and contactor mounting. Siemens specifies screw terminals for both the main and auxiliary circuits, along with manual and automatic reset.

Siemens SIRIUS 3RB3 Electronic Overload Relay

The 3RB3036-1UB0 belongs to the Siemens SIRIUS 3RB30 electronic overload relay family, designed for electronic monitoring and protection of industrial motors.

The relay continuously evaluates motor current and provides a defined Class 10E overload response. Its S2 contactor-mounting design allows integration into compatible Siemens SIRIUS motor-starter assemblies.

Typical applications include:

• Industrial motor control

• Pumps

• Fans and blowers

• Compressors

• Conveyors

• Production machinery

• Machine tools

• Process equipment

• Industrial automation

• OEM control panels

Adjustable 12.5–50 A Current Range

The 3RB3036-1UB0 provides an adjustable current-setting range of 12.5 to 50 A, with a specified thermal current of 50 A.

This range allows the overload 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.

Class 10E Trip Characteristic

The exact 3RB3036-1UB0 is a Class 10E electronic overload relay. Siemens' current 2025/2026 core catalog lists 3RB3036-1UB0 under the S2, 12.5–50 A, Class 10E contactor-mounted electronic overload relays.

Class 10E provides a defined overload tripping characteristic for motors with corresponding starting requirements. The selected trip class should be matched to the motor starting time and application conditions.

Electronic Overload Protection

The primary function of the 3RB3036-1UB0 is electronic motor-overload protection.

The relay continuously monitors 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

• Unsuitable motor-starting conditions

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

Phase-Failure and Asymmetry Protection

The Siemens 3RB30 electronic overload relay family provides overload, phase-failure and asymmetry protection. Siemens' product documentation lists these as core protection functions of the 3RB30 range.

Phase failure or significant current imbalance can result in abnormal motor heating and operating stress. Electronic monitoring therefore provides broader protection for three-phase motors than overload protection alone.

1 NO + 1 NC Auxiliary Contacts

The Siemens 3RB30 Class 10E range provides 1 normally open (NO) and 1 normally closed (NC) auxiliary contact for control and signalling functions.

These 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 3RB3036-1UB0 is designed for contactor mounting and belongs to Size S2. Siemens' current catalog specifically places this article in the S2, 12.5–50 A Class 10E contactor-mounted range.

This allows it to form part of a compact motor-starter assembly with a compatible Siemens SIRIUS contactor.

Typical applications include:

• Motor starters

• Industrial control panels

• Automation cabinets

• OEM machinery

• Process-control systems

Screw-Terminal Connections

The 3RB3036-1UB0 uses screw connections for the main and auxiliary circuits. Siemens' current datasheet specifies screw terminals for both circuits.

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

Manual and Automatic Reset

The exact 3RB3036-1UB0 supports manual and automatic RESET. Siemens' datasheet identifies both reset modes for the product.

The specified typical recovery time after an overload trip is approximately 3 minutes with automatic reset, while manual and remote reset conditions are specified at 0 minutes under the relevant conditions.

The appropriate reset method should be selected according to the machine and control-system design.

TEST Function and Self-Monitoring

The Siemens 3RB30 electronic overload relay range includes TEST functionality, switch-position indication and self-monitoring.

These functions can support:

• Commissioning

• Functional testing

• Troubleshooting

• Preventive maintenance

• Control-panel servicing

Electrical and Environmental Characteristics

The 3RB3036-1UB0 has an insulation voltage of 690 V and 6 kV surge-voltage resistance. Siemens specifies approximately 1.8 W total power loss at rated current in the hot operating state, or about 0.6 W per pole.

The relay is specified for an operating ambient temperature range of -25 °C to +60 °C, with temperature compensation over that range, and an installation altitude of up to 2,000 m.

These characteristics should be considered during motor-control-panel design and installation.

Industrial Motor-Control Applications

Pumps

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

Fans and Blowers

The Class 10E characteristic can be used for motors with corresponding 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.

Production Machinery

The S2 construction is suitable for medium-current industrial motor-control assemblies.

Process Automation

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

Suitable for OEMs and Panel Builders

The 3RB3036-1UB0 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 12.5–50 A adjustable current range, Class 10E protection, S2 contactor mounting, phase-failure and asymmetry protection, screw-terminal connections and manual/automatic reset makes it suitable for a wide range of industrial motor-protection applications.

Key Features

• Siemens SIRIUS 3RB3 electronic overload relay

• Article number 3RB3036-1UB0

• Microprocessor-based electronic overload protection

• 12.5–50 A adjustable current range

• Class 10E

• Size S2

• 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

• 12.5–50 A adjustable range: Suitable for a broad range of medium-current industrial motors.

• Class 10E: Provides a defined overload characteristic for compatible motor-starting requirements.

• Electronic monitoring: Provides continuous evaluation of motor current.

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

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

• Contactor mounting: Supports compact S2 motor-starter assemblies.

• Screw terminals: Provides a familiar industrial wiring method.

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

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

• Compact S2 design: Helps integrate the relay into industrial control panels.

Why Choose Siemens 3RB3036-1UB0?

The Siemens 3RB3036-1UB0 is a practical electronic overload relay for motor protection in the 12.5–50 A range with a Class 10E trip characteristic.

Its combination of electronic overload protection, phase-failure and asymmetry protection, S2 contactor mounting, 1 NO + 1 NC auxiliary contacts, screw connections and manual/automatic reset makes it suitable for motor starters, industrial automation panels and OEM machinery.

The current Siemens catalog also confirms this exact article as the 12.5–50 A Class 10E S2 contactor-mounted version, distinguishing it from the nearby 3RB3036-1WB0, which is the 20–80 A version.

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 3RB3036-1UB0?

It is a Siemens SIRIUS 3RB3 electronic overload relay for motor protection with a 12.5–50 A adjustable current range and Class 10E characteristic.

2. What is the current setting range?

The adjustable current range is 12.5–50 A.

3. What is the trip class?

The exact 3RB3036-1UB0 is Class 10E.

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 3RB3036-1UB0 is designed for S2 contactor mounting.

7. Does it use screw terminals?

Yes. Siemens specifies screw connections 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 family.

10. Where can I buy Siemens 3RB3036-1UB0 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.