Lovato RF420250 is a three-pole Class 10A thermal overload motor protection relay with a 150-250 A operational current range and manual or automatic resetting.
SKU:RF420250MPN:RF420250
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Why Choose the Lovato RF420250 Motor Protection Relay?
The Lovato RF420250 is a high-capacity three-pole thermal overload motor protection relay designed to protect industrial three-phase motors against overload conditions. Part of the Lovato RF420 motor protection relay series, it provides an adjustable operational current range of 150–250 A for demanding motor control applications.
The RF420250 features a Class 10A thermal release, manual or automatic resetting, integrated test button and trip indicator. Designed for high-current motor protection systems, it supports reliable operation and straightforward maintenance in industrial electrical installations.
With a rated operational voltage of 690 V, rated insulation voltage of 1000 V and IP20 frontal protection, the RF420250 is suitable for large motor starters and industrial control panels. Its screw fixing arrangement and auxiliary contacts provide flexible installation and control integration.
Key Advantages
150–250 A adjustable operational current range for high-current motor protection.
Three-pole thermal overload relay for three-phase motor applications.
Class 10A tripping characteristic for reliable motor overload protection.
Selectable manual or automatic reset for flexible operation.
Integrated test button and trip indicator simplify commissioning and maintenance.
1NO + 1NC auxiliary contacts for control and signalling circuits.
Key Features
Lovato RF420 motor protection relay series.
150–250 A operational current range.
690 V rated operational voltage.
1000 V rated insulation voltage Ui.
6 kV rated impulse withstand voltage Uimp.
Class 10A thermal overload protection.
IP20 frontal protection rating.
Manual or automatic resetting.
Integrated test button and trip indication.
1NO + 1NC auxiliary contacts.
Reliable Thermal Overload Protection for Industrial Motors
Thermal overload relays protect motors by monitoring current levels and responding when sustained overload conditions occur. The Lovato RF420250 provides adjustable high-current protection for large three-phase motors used in industrial equipment and electrical installations.
With manual or automatic resetting, integrated testing facilities and auxiliary contacts, the RF420250 supports dependable motor starter operation while simplifying maintenance and fault identification.
Typical Applications
Large three-phase industrial motor protection.
Motor starters and motor control centres.
Industrial machinery and production equipment.
Pumps, fans and heavy-duty drive systems.
Electrical control panels and switchgear.
Industrial automation and process equipment.
Technical Specifications
HS Code
85364900
Manufacturer
Lovato Electric
Series
RF420
Model
RF420250
Product type
Thermal overload motor protection relay
Number of poles
3
Release type
Thermal
Operational current
150–250 A
Rated operational voltage
690 V
Rated insulation voltage Ui
1000 V
Rated impulse withstand voltage Uimp
6 kV
Operational frequency
50–60 Hz
Tripping class
10A
Phase failure detection
No
Reset mode
Manual or automatic
Test button
Yes
Trip indicator
Yes
Auxiliary contacts
1 NO + 1 NC
Frontal protection rating
IP20
Fixing type
Screw fixing
Power terminal type
Screw and flat washer
Power terminal size
M10
Auxiliary terminal size
M3.5
Operating temperature
-25–60 °C
Storage temperature
-50–70 °C
Maximum altitude
3000 m
Weight
2460 g
Frequently Asked Questions
What is the Lovato RF420250 used for?
The RF420250 is a three-pole thermal overload motor protection relay designed to protect high-current three-phase motors against overload conditions.
What is the current range of the Lovato RF420250?
The RF420250 has an adjustable operational current range of 150–250 A.
What tripping class does the RF420250 use?
The Lovato RF420250 has a Class 10A tripping characteristic.
Can the Lovato RF420250 be reset automatically?
Yes. The RF420250 supports both manual and automatic resetting.
Does the RF420250 include auxiliary contacts?
Yes. The relay includes 1 NO and 1 NC auxiliary contacts for control and signalling applications.
Trusted Motor Protection from Lovato Electric
The Lovato RF420250 provides high-current thermal overload protection, flexible resetting and integrated control features for reliable motor protection in demanding industrial applications.
HS Code
85364900
Manufacturer
Lovato Electric
Series
RF420
Model
RF420250
Product type
Thermal overload motor protection relay
Number of poles
3
Release type
Thermal
Operational current
150–250 A
Rated operational voltage
690 V
Rated insulation voltage Ui
1000 V
Rated impulse withstand voltage Uimp
6 kV
Operational frequency
50–60 Hz
Tripping class
10A
Phase failure detection
No
Reset mode
Manual or automatic
Test button
Yes
Trip indicator
Yes
Auxiliary contacts
1 NO + 1 NC
Frontal protection rating
IP20
Fixing type
Screw fixing
Power terminal type
Screw and flat washer
Power terminal size
M10
Auxiliary terminal size
M3.5
Operating temperature
-25–60 °C
Storage temperature
-50–70 °C
Maximum altitude
3000 m
Weight
2460 g
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Delivery
We offer fast UK delivery on all stocked items. Orders placed before 3pm Monday to Friday are eligible for next-day delivery.
Standard delivery: 2–3 working days
Next-day delivery: available on in-stock items when ordered before 3pm
Express options available — contact us for details
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2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...