FCMOV Product Introduction

Current Status of Overvoltage Protection

Metal Oxide Varistors (MOVs) have long been a widely used solution for overvoltage circuit protection. They are highly cost-effective and an ideal choice for transient surge protection. However, prolonged and repeated exposure to overvoltage can generate excessive current, which may lead to thermal runaway. Unfortunately, the thermal-protection alternatives available in the market are often bulky and expensive.

MOVs can also be affected by continuous abnormal voltages from the power grid, not just short transient events. If a varistor is subjected to sustained abnormal overvoltage or overcurrent conditions (such as those required under the UL 1449 safety standard), it may enter a state of thermal runaway, leading to overheating, smoking, and even fire hazards. Beyond the failure of a low-cost component, such events may result in massive compensation claims, lawsuits, and other serious consequences.

For products to comply with UL 1449 safety standards, MOVs must provide a certain degree of fail-safe protection. In essence, this refers to a varistor’s ability to withstand power-frequency overvoltage. Whether or not an MOV can endure such power-frequency overvoltage in low-voltage systems directly affects the safety of electrical systems. Therefore, transient overvoltage tolerance is a critical safety characteristic. If a varistor cannot withstand power-frequency overvoltage, short circuits and breakdown failures will inevitably occur, which can cause overheating around the MOV and potentially trigger fire or even larger hazards.

Our Solution – FCMOV

FCMOV is a combination of a PPTC resettable fuse and a Metal Oxide Varistor (MOV). By integrating overcurrent and overvoltage protection, it ensures safer circuit operation. When exposed to sustained overcurrent, this hybrid device will trip and open the circuit, thereby protecting the MOV and greatly reducing the risk of catastrophic failure.
In addition, since the PPTC functions as an embedded sensing element, it provides a more accurate and reliable mechanism compared to other temperature-sensing devices. It suppresses the destructive effects of high surge currents, thereby extending not only the lifespan of the MOV but also the overall service life of the equipment.

FCMOV1

As a resettable electronic protection component, the PPTC automatically resets once the fault condition is cleared. In the case of temporary faults, this greatly reduces maintenance requirements. Today, it is widely used in industrial automation, urban lighting, and other related applications.

PPTC: Inactive
Remain at low resistance status and let the current flow through.
MOV: Activated
Resistance drop, absorb the transient Voltage & energy and dissipates it as heat.
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PPTC: Inactive → MOV: Activated → Partial Operation
The temperature decreases to a non-catastrophic level, thereby preventing the varistor from entering thermal runaway (thermal cycling).

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FCMOV Features and Comparison with Other MOVs

Hybrid Component Design: Utilizes patented Polymer Positive Temperature Coefficient (PPTC) and Metal Oxide Varistor (MOV) technologies
Standard Disk Sizes: Available in 10 mm, 14 mm, and 20 mm packages
Integrated Protection: Provides high-level overvoltage and overcurrent protection
Voltage Sharing: When the PPTC trips, it also shares voltage with MOV

FCMOV vs TMOV vs MOV

	FCMOV	Competition TMOV	Regular MOV
Protection Mechanism	PPTC(Current & Thermal)	TCO(Thermal)	None
Reponse Time	Typically < 1 sec (Better)	2-25 Sec
Safety Level	High	Med	Low
Resettable	Yes	No
Cost	Med	High	Low
Custom Design	Custom design available	Standard part only

Hybrid Design: Incorporates patented PPTC technology
Standard Packages: Available in 10 mm, 14 mm, and 20 mm MOV diameters
Integrated Protection: Provides high-level overvoltage and overcurrent protection
Voltage Sharing: When the PPTC trips, voltage is divided across the circuit
Customizable: Can be tailored to meet specific application requirements
Faster Response: Offers quicker protection than typical TMOV (MOV with built-in fuse) devices
Resettable: Reusable design reduces maintenance work
Extended Lifespan: Overcurrent protection helps extend the life of both the MOV and the end product

FCMOV Product Introduction

Current Status of Overvoltage Protection

Our Solution – FCMOV

FCMOV Features and Comparison with Other MOVs

Conventional Metal Oxide Varistor (MOV) – Abnormal Voltage Condition

Conventional Metal Oxide Varistor (MOV) – Abnormal Voltage Condition (10A Actual Test)

FCMOV Hybrid Varistor – Abnormal Voltage Condition (i)

FCMOV Hybrid Varistor – Abnormal Voltage Condition (ii)

FCMOV vs. TMOV

FCMOV Product Summary