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Thermal Overload Relays for AC Motor Protection
KRIPAL manufactures thermal overload relays as direct-mount protection devices for UKC contactors, providing Class 10A and Class 20 tripping characteristics with phase-loss sensitivity and ambient temperature compensation per IEC 60947-4-1. The UKH series spans 0.1A to 630A with adjustable setting ranges, offering both direct mounting on UKC contactors and separate mounting with terminal blocks for panel installations. Each relay includes one NO and one NC auxiliary contact for trip indication and control circuit integration in motor starter assemblies.
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UKH-150 Thermal Overload Relay 34-150A Contact Rating 3P 1NO + 1NC
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-220 Thermal Overload Relay 65-240A Contact Rating 3P 1NO + 1NC
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-630 Thermal Overload Relay 220-630A Contact Rating 3P 1NO + 1NC
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-100 Thermal Overload Relay 34-125A Contact Rating 3P 1NO + 1NC
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-22 Thermal Overload Relay 0.1-22A Contact Rating 3P 1NO + 1NC UL Listed
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-40 Thermal Overload Relay 4-40A Contact Rating 3P 1NO + 1NC UL Listed
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH-85 Thermal Overload Relay 7-85A Contact Rating 3P 1NO + 1NC UL Listed
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
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UKH Mini Thermal Overload Relay 0.1-16A Contact Rating 1NO + 1NC
UKH Thermal Overload Relay is manufactured in compliance with the GB/T 14048.4 standard.
Ask a QuoteThermal Overload Relay Selection Guide for Motor Protection
A thermal overload relay detects sustained overcurrent conditions and initiates a circuit trip sequence before motor windings exceed safe thermal limits. The KRIPAL UKH series utilizes bimetallic, temperature-compensated mechanisms to provide precise phase current monitoring, built specifically to integrate with industrial export motor starter assemblies.
Technical Specifications of the UKH Series
Amperage Range: 0.1A to 630A
The UKH-22 through UKH-630 frame sizes, alongside dedicated miniature models, accommodate a comprehensive spectrum of motor loads for deployment within compact control panel architectures.
Direct Plug-In Mounting
Engineered for seamless mechanical coupling. These thermal units plug directly into the load terminals of UKC1, UKC2, and UKC5 contactors, eliminating the requirement for secondary wiring loops.
Class 10A and 20A Trip Curves
Calibrated to match specific mechanical profiles. Class 10A secures standard squirrel-cage motor loads, while Class 20A accommodates the extended acceleration parameters of high-inertia drives.
North American UL Compliance
The UKH-22, UKH-40, and UKH-85 hardware platforms maintain comprehensive UL listings, fulfilling strict regulatory demands for motor starter components exported into the United States and Canada.
Enhanced Phase-Loss Sensitivity
The specialized UKK variant integrates an advanced phase-loss detection mechanism designed for rapid circuit isolation during single-phase fault conditions. This provides critical protection against catastrophic motor failure, ensuring operational reliability in unbalanced load environments.
Global OEM Motor Protection with UKH Overload Relays
KRIPAL UKH thermal overload relays provide precise bimetallic protection for three-phase induction motors across global OEM equipment platforms—from compact fractional-horsepower drives to heavy industrial motors requiring Class 10 and Class 20 trip characteristics.
OEM Motor Control Panel Integration
UKH relays pair with UKC contactors as standardized motor starter combinations in OEM control panels exported worldwide. Direct mounting to the contactor eliminates separate DIN rail space and simplifies panel layout for high-volume equipment manufacturers.
High-Inertia Load Motor Protection
Class 20 UKH models protect motors driving centrifugal fans, flywheel-equipped presses, and large conveyor systems where extended acceleration times would trip a standard Class 10 relay before the motor reaches running speed.
Multi-Motor and Group Installation Protection
UKH relays protect individual motors in multi-pump skids, HVAC fan arrays, and conveyor system motor groups where selective trip coordination ensures a single motor fault does not cascade into a full system shutdown.
Standardize Your Motor Protection Worldwide
- Global Compliance Ready: UKH relays carry essential CE and IEC certifications, ensuring seamless regulatory acceptance across European, Asian, and Middle Eastern markets to simplify your equipment’s international market entry.
- Dedicated Application Engineering: Our team reviews your motor list and load characteristics to specify the correct relay class, setting range, and mounting configuration for each drive in your equipment.
- OEM Volume & Inventory Programs: Benefit from factory-direct pricing and managed safety stock. We ship against your production forecast, helping you optimize your supply chain and minimize the working capital tied up in component inventory.
UKH Overload Relay Manufacturing: Calibration and Global Logistics
KRIPAL UKH thermal overload relays are manufactured on the same integrated production lines as our UKC contactors. Each unit undergoes rigorous bimetallic calibration to ensure consistent trip characteristics across the entire 0.1A to 630A range. By offering both Class 10 and Class 20 options for standard and high-inertia applications, we provide OEMs and panel builders with a reliable, single-source motor protection partner.
Temperature-Compensated Bimetal Calibration
UKH relays are calibrated in ambient-temperature-controlled test stations that compensate for environmental conditions, ensuring the trip curve remains accurate whether the relay is installed in an air-conditioned control room or a Middle Eastern pump house.
Single-Phase Sensitivity Verification
The differential trip mechanism that detects phase loss is tested on every production batch. A motor running on two phases draws 1.73x normal current in the remaining windings | the UKH differential trip catches this before winding insulation breaks down.
Class 10 and Class 20 Trip Curve Options
Standard Class 10 for general-purpose motors, Class 20 for high-inertia loads | both manufactured and calibrated on the same production line with consistent quality standards across the range.
Direct Mount to UKC Contactors Without Tools
UKH relays snap directly onto UKC contactors without adapter plates or tools, sharing the contactor’s three-phase terminals. This reduces panel assembly labor and eliminates the wiring errors that occur with separately mounted overloads.
OEM Motor Protection Standardization Worldwide
For equipment manufacturers exporting to multiple regions, UKH relays carry CE and IEC certifications accepted across Europe, Asia, and the Middle East | one relay series covers your global markets without regional variants.
Distributor Stock with Pre-Set Overload Ranges
KRIPAL warehouses UKH relays in the most-demanded current ranges for distributors who need off-the-shelf availability. Popular ranges ship same-day; custom ranges ship within agreed lead times.
Private Label with Trip Setting Dial Marking
Your brand and part number laser-etched on the relay body, with the trip setting range clearly marked. KRIPAL’s factory identity does not appear on the finished product.
Direct Motor Protection Engineering Support
OEM and panel builder engineers speak directly with KRIPAL’s motor protection team for trip class selection, coordination with upstream protection devices, and application-specific mounting guidance | no distributor-intermediated technical communication.
Frequently Asked Questions
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AC Contactors and Thermal Overload Relays Selection Guide with Star Delta Solutions
Master the selection of contactors and overload relays in your Star Delta starter setup to avoid sizing errors and ensure optimal performance.
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