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UV-C Ballast Start Types

While UV-C germicidal technology tends to get all the attention, UV-C ballasts are literally driving the UV-C revolution. One of the main design features of a UV-C ballast is the starting mechanism or ballast start type. There are three main ballast start types: Instant Start Ballasts (IS), Rapid Start Ballasts (RS) and Programmed Start Ballasts (PS). Understanding these three features is critical when designing an application or device that utilizes UV-C lamps. Typically, the UV-C lamps that will require a UV ballast are either Mercury or Amalgam based.

UV-C ballasts need to be tailored to the application’s use case. The on/off duty cycle of the lamp within an application is critical in determining the proper ballast start type. Each ballast start type is optimized for different working conditions. Due to various use cases and duty cycles, some ballasts are designed to maximize the life of the lamp, while others are made as simple as possible to reduce design and production costs. Determining the balance between lamp life and cost will allow you to choose the best ballast start type for your next project. Continue to read this design note to learn more on the specifics of each ballast start type.

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Instant Start Ballast

An Instant Start ballast design applies a high voltage directly to the electrodes without any preheating aspect. This sparks the lamp immediately, but can cause some initial flickering as the electrodes heat up by the electrical arc within the lamp. This starting mechanism is the cheapest but also the harshest on the lamp resulting in reduced lamp life. Instant start ballasts are best suited for devices where the lamp is illuminated a handful of times throughout its useful life and stays on for extended periods of time.

Rapid Start Ballast

A Rapid Start ballast applies current to the electrodes at the same time as the strike voltage. The current warms the electrode but since there isn’t time between the two mechanisms, the electrodes can spark before they are heated sufficiently. This start is an “in-between” for the other two staring mechanisms. It’s more cost efficient than a programmed start design and not as hard on the electrodes as the instant start. A rapid start ballast helps prolong the life of lamps, when compared to an instant start ballast. Rapid start ballasts are best suited for lamps that have a low to medium on/off cycle. Rapid Start ballasts tend to be the most popular choice amongst industrial customers.

Programmed Start Ballast

In a Programmed Start Ballast a voltage is applied to the electrode that is too low to start the lamp but preheats the electrodes. After a set amount of “preheat” time, the high sparking voltage is applied. These two steps are pre-programmed into the ballast’s circuitry. This typically delays the illumination of the lamp by a few seconds but it greatly improves lamp life, especially in applications where there are multiple starts per day. A programmed start ballast is best suited for applications with a high on/off cycle.  The program start feature requires more complex components in the ballast circuitry which comes with a slight cost premium. These are also the better starting type for high output UVC lamps, >800mA.

UV-C Ballast Start Types

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Additional Customization

ISL Products designs and manufactures a variety of electronic ballasts for UV-C lamps. We specialize in both standard and value-added ballast designs. In addition to ballast starting mechanisms, ISL Products has the ability to design a ballast based on your power, voltage and connection requirements. Current designs have been created to work on a variety of input voltages such as 12VDC, 24VAC as well as 110/220 VAC with automatic switching. Whatever your design requires, we can provide a suitable solution.

For applications that require high output (HO) lamps and/or need to run multiple lamps with a single ballast, we have a solution for that as well. We offer standard push terminals, bulb specific sockets, and also the ability to integrate most header/connector types into the housing and PCB design. Custom housings are also available for any application.

ISL Products has been manufacturing ballasts for UV-C lamps for over 15 years. We’ve designed hundreds of different ballasts for just as many use cases. From HVAC units to water purification appliances, we have the ballast for you.

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