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Overload relays are crucial safety devices that protect electric motors from damage caused by overcurrent conditions. Selecting the appropriate overload relay ensures motor longevity, prevents costly downtime, and maintains operational safety in industrial settings. Understanding the key features and specifications will help you make an informed purchase.
✅Package Content: 1 x Starter Relays 4.7 ohm 3Pin + 1 x Refrigerator Overload Protector 1/2HP.
✅Please note that this product is only compatible with QP-02-4.7 relay with 3 terminals. Not compatible with relays of other pin numbers. This kit is not suitable for all refrigerator compressors, only applicable to 110V compressors.
✅【Note】The maximum current that a 4.7 ohm relay can withstand is 12A. otherwise it will burn.
✅【Note】Please carefully compare the pictures we provide with your old parts. Please check if your old relay is 3 pins. To make sure it fits your refrigerator. please consider before buying.
This thermal overload relay can be used in a network frequency of 0-4000hz, the rated insulation is 600V cUL / 690V IEC, and tripping class 10, for protection of 3-phase motors for HVAC, elevators, pumps or compressors, and agriculture
It features a compact and modular design, making it an ideal solution for space-constrained applications and can be quickly and easily configured to meet the needs of your specific application
A reliable and cost-effective solution for protecting your motor against overloads, phase failures, and phase unbalances; durable, compact design to protect from dust and other environmental elements
The thermal overload relay has phase-break protection, manual and automatic reset, temperature compensation, trip indication, test button, stop button
🧊What You Get:2 pieces of 4.7 Ohm 1-pin PTC start relay and 2 pieces of 6750C-0005P refrigerator overload protector, totally 2 sets of 4 for you, convenient to replace the old or broken part of your refriger.All the sets comes with a White Paper Box to...
🧊Compatible models: suitable for most brands in the market that uses 1 Pin QP2 4.7 Ohm Resistance.The refrigerator overload protector can prevent the compressor in your refrigerator from overheating.Nice to replace part numbers like AP...
🧊PTC Starter Relay:It's the generic starter relay applied on various brands of mini fridges and coolers, saving your time and effort, this item is ONLY compatible with QP2-4.7 one-terminal relay.
🧊Easy Install Replace and Widely Applied: Easy to install for direct replacement, which will work and restore cool air to your refrigerator.Quickly repair mini fridges, compact refrigerators, beverage and wine/beer coolers, chest freezer，deep...
This thermal overload relay can be used in a network frequency of 0-4000hz, the rated insulation is 600V cUL / 690V IEC, and tripping class 10, for protection of 3-phase motors for HVAC, elevators, pumps or compressors, and agriculture
It features a compact and modular design, making it an ideal solution for space-constrained applications and can be quickly and easily configured to meet the needs of your specific application
A reliable and cost-effective solution for protecting your motor against overloads, phase failures, and phase unbalances; durable, compact design to protect from dust and other environmental elements
The thermal overload relay has phase-break protection, manual and automatic reset, temperature compensation, trip indication, test button, stop button
Package Content: you will get 1 piece of 4.7 Ohm 1 pin PTC start relay and 1 piece of 6750C-0005P refrigerator overload protector, totally 2 pieces for you, convenient to replace the old or broken part of your refrigerator; Please note the item is only...
Compatible Models: the refrigerator overload protector can prevent the compressor in your refrigerator from overheating, nice to replace part numbers like AP4439459, 1357963, AH3529540, EA3529540, PS3529540, you can check the product description for list...
PTC Starter Relay: the PTC start relay is the universal starter relay applied on mini fridges and coolers, saving your time and effort, this item is only compatible with QP2-4.7 one terminal relay, please do consider this before purchasing
Easy to Install: refrigerator starter relay is made of plastic, the overload protector is made of plastic and brass, both materials are durable, reliable and rust resistant, also easy to install for direct replacement, which will work and restore cool air...
Package Included: You will get 1x 4.7 Ohm 1 pin PTC start relay and 1x 1/2HP Refrigerator overload protector
Replaces part numbers like AP4439459, 1357963, AH3529540, EA3529540, PS3529540.
1 Pin Refrigerator Starter Relay with 6750C-0005P Refrigerator Overload Protector
Widely applied: Suitable for various of most mini fridges, compact refrigerators, beverage & wine/beer coolers, deep freezers, chest freezer, beer/wine refrigerators, Easy to install
RATED RANGE: This thermal relay can be used in the circuit of 50-60hz, the rated insulation voltage is 690V.
SPECIFIC FUNCTION: The overload protection relay has phase break protection, manual and automatic reset, temperature compensation, trip indication, test button, stop button.
GOOD PROTECTION: The relay is used for protecting the phase break when the electric motor is overload.
Last update on 2026-10-16 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Overload Relays
Understanding Overload Relay Types
Overload relays are primarily categorized by their tripping mechanism. The most common types include:
Thermal Overload Relays: These use bimetallic strips that bend when heated by excessive current, triggering a trip mechanism. They are popular due to their simplicity and cost-effectiveness.
Electronic Overload Relays: These offer more advanced features like adjustable trip settings, phase loss detection, and communication capabilities. They provide greater precision and flexibility.
Magnetic Overload Relays: These react to sudden short-circuit currents by using an electromagnet. They are typically used in conjunction with other relay types for enhanced protection.
Key Specifications to Consider
When choosing an overload relay, several specifications are vital:
Current Rating: The relay must be rated to handle the motor's full load amperage (FLA). Ensure the adjustable range covers your motor's requirements.
Trip Class: This indicates how quickly the relay will trip under varying overload conditions. Class 10 (trips within 10 seconds at 6 times FLA) is common, but Class 20 or 30 may be suitable for certain applications.
Voltage Rating: The relay's voltage rating must be compatible with your system's voltage.
Phase Loss Protection: Crucial for three-phase motors, this feature prevents damage if one phase of the power supply is lost.
Reset Type: Relays can be manual (requiring a button push to reset) or automatic (resetting when conditions return to normal). Manual reset is often preferred for safety to ensure the cause of the overload is identified.
Application and Environment
Consider the operating environment and the specific application. Relays designed for harsh environments may have higher IP ratings for dust and water resistance. For applications with frequent starts or high inrush currents, a slower trip class or an electronic relay with adjustable settings might be more appropriate to prevent nuisance tripping.
Comparison Tips
When comparing different models, look beyond the basic specifications. Consider:
Brand Reputation: Established manufacturers often offer reliable products and better support.
Integration: If you're using a motor control center, ensure the relay is compatible with other components.
Additional Features: Some relays offer remote reset, alarm contacts, or diagnostic capabilities. Evaluate if these add value to your specific setup.
Frequently Asked Questions
What is the difference between a thermal and electronic overload relay?
Thermal overload relays use bimetallic strips that heat up and bend to trip, offering simplicity. Electronic overload relays use solid-state components for more precise control, adjustable settings, and advanced features like phase loss detection.
What does 'Trip Class' mean for an overload relay?
Trip class defines the time it takes for the relay to trip under a specific overload condition, usually expressed as a multiple of the full load ampere (FLA). For example, a Class 10 relay will trip within 10 seconds at 6 times the FLA.
Why is phase loss protection important?
Phase loss protection is vital for three-phase motors. If one phase of the power supply is lost, the motor can overheat and sustain damage. This feature detects the loss and trips the relay to protect the motor.
Should I choose a manual or automatic reset overload relay?
Manual reset relays require a user to physically reset them after a trip, ensuring the cause of the overload is investigated. Automatic reset relays revert to normal operation when the overload condition is cleared, which can be convenient but may mask underlying issues.
How do I determine the correct current rating for my motor?
You should select an overload relay with a current rating that matches or slightly exceeds the motor's full load amperage (FLA), which is typically found on the motor's nameplate. The relay's adjustable range should encompass this FLA.
Can an overload relay protect against short circuits?
Overload relays are primarily designed to protect against sustained overcurrents that cause gradual overheating. They typically do not provide protection against instantaneous short circuits; separate short-circuit protection devices like fuses or circuit breakers are needed for that.
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