An Overview of Power Supplies for OVC III Applications


Power system overvoltage can wreak havoc with a power supply, leading to higher risks of damaged hardware and equipment. Therefore, equipment needs to run at a steady voltage on an ongoing level to operate properly. In the case of overvoltage, more pressure is put on the overall power supply as the voltage suddenly increases and exceeds its design limit.

Power system overvoltage can be divided into two main categories: internal and external. Depending on the cause, internal overvoltage can be further divided into switching and temporary overvoltage. Independently from the exact causes, overvoltage impacts the reliability of a power supply system while shortening the equipment's lifespan through overheating and increased power consumption.


Overvoltage is not an uncommon occurrence and it most frequently happens when a high volume of power is consumed or in the case of a sudden break in currents. Electrical engineers should consider this aspect during their electrical projects' design and implementation process. Below we will review how equipment is usually divided into four main categories based on its overvoltage resistance levels.


Overvoltage Categories (OVC)

With electrical systems becoming increasingly complex, the chances of incurring overvoltage also increase. In accordance with IEC specifications, four overvoltage categories are defined for guaranteeing adequate user safety. Each installation category is labeled by a Roman numeral according to the potential for transient overvoltage to occur. The Overvoltage Category (OVC) I describe the environments with the lowest transient overvoltage, where OVC IV refers to the worst and most demanding applications.

Overvoltage Categories

Below we will briefly review the main differences between each power supply overvoltage category:

● OVC I refers to the overvoltage of the electrical equipment connected to the circuit, which has taken measures to suppress the transient overvoltage to a level where no hazard can be caused;

● OVC II refers to the energy-consuming equipment intended to be supplied from the building wiring, including both plug-connected and permanently connected equipment (for example, the various household appliances or similar loads);

● OVC III refers to the overvoltage for equipment intended to form part of a building wiring installation or with higher requirements for reliability and availability (for example, socket-outlets and distribution boards);

● OVC IV refers to the overvoltage of the equipment used at the entrance of a building or in the main distribution board (for example, electricity meters and primary overcurrent protection equipment).


OVC III Applications

OVC III equipment can be used for a wide range of applications, especially where high reliability is a crucial necessity. OVC III equipment is often implemented in the following environments:


OVC III Applications

1. Industrial applications

OVC IIImachineryincludesthe hard-wired equipment fitted inside a switch cabinet or distribution panel. Some OVC III power supplies applications include relays, circuit breakers, and fixed-installation power supplies. An example could include industrial machinery which is hard-wired to the AC supply. Besides fixed-installation equipment, OVC III power supplies can also be used for robots and other machine controllers, which need a greater degree of protection from input voltage line transients. In these applications, OVC III power supplies enable direct connection to the incoming AC distribution panel, saving the cost and space of an isolation transformer.


2. Domestic applications

OVC III equipment can be seen in a house fuse panel or similar environments. In these applications, OVC III converters can appear in the energy distribution panel to support the transmission of power from an OVC IV power meter. OVC III converters enable safe and reliable energy transfer to OVC II outlets, where many plug-in household appliances obtain power. In these locations with more severe transient amplitudes and energy levels, power converters need to provide additional overvoltage protection compared to that required for a plug-in power supply.


More generally, OVC III also applies to equipment subjected to special requirements in terms of reliability and availability. In fact, OVC III power systems are often used in indoor applications where the negative consequences of overvoltage can impact the equipment's lifespan and the safety of the people involved.


Besides higher reliability, the benefits of using OVC III power supplies include decreased size and cost of the final system, thus leading to increased market competitiveness.


MORNSUN's OVC III Power Supply Solutions

Selecting a reliable power supply system belonging to the most suitable OVC is the best way to protect the equipment from damage and power interruptions resulting from overvoltage. For example, MORNSUN has a range of standard power converters for OVC II and OVC III applications.


MORNSUN's OVC III Power Supply Solutions

MORNSUN's power supplies are known in the industry for their high reliability and long-lasting performance. The LH-R2 series is a collection of AC/DC converters that are designed with higher input-overvoltage capability for use in category III fixed applications. The LD-R2 series is not only compatible with category III applications, as it allows for a wide range of uses across I/II/III overvoltage category environments. With its wide application range, this series of AC/DC converters provide one of the highest cost-performance ratios.


The LD-R2 incorporates compact and robust design features, a wide input-voltage range up to 305 VAC, an operating temperature range spacing from -40 ° C to + 85 ° C, and an up to 87% high efficiency. This series of EMI-Class-B MORNSUN AC/DC converters also conforms to IEC/EN/UL62368/EN60335/EN61558 standards.


Contact us to see how MORNSUN's power supply solutions can help you manage the effect of overvoltage on your power supply.   

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