Effects of Brownouts on Electrical Apparatus
– Different types of electrical apparatus react differently to voltage reduction.
– Some devices are severely affected by brownouts, while others may not be affected at all.
– Resistive loads, such as electric space heaters, experience a significant reduction in heat output with a relatively small reduction in voltage.
– Incandescent lamps dim due to lower heat creation in the filament and lower conversion of heat to light.
– Motors, like universal motors, run at reduced speed or torque and may draw more current under load, leading to overheating and burnout.
Impact on Power Supplies
– Unregulated DC supplies produce a lower output voltage during brownouts.
– The output voltage ripple decreases with the usually reduced load current.
– Linear DC regulated supplies maintain the output voltage unless the brownout is severe and the input voltage drops below the regulator’s drop out voltage.
– Switched-mode power supplies are affected if the brownout voltage is lower than the minimum input voltage, causing increased current draw or malfunction.
– Cathode-ray tube televisions display smaller, dimmer, and fuzzier images due to reduced output voltage.
Effects on Digital Systems
– Brownouts can cause unexpected behavior in systems with digital control circuits.
– Reduced voltages can bring control signals below the threshold for reliable detection of logic circuit states.
– The return to normal voltage levels can cause incorrect latching of logic states, even leading to impossible states.
– The severity of this effect and the need for preventive measures depend on the equipment being controlled.
– For example, a brownout may cause a motor to run backwards.
Related Concepts
– Black start
– Dumsor
– Power outage
– Voltage drop
References
– Añel, Juan; Fernández-González, Manuel; Labandeira, Xavier; López-Otero, Xiral; de la Torre, Laura (October 27, 2017). Impact of Cold Waves and Heat Waves on the Energy Production Sector.
– Wyatt, Alan (1986). Electric Power: Challenges and Choices.
– Blume, Steven Warren (2007). Electric Power System Basics: For the Nonelectrical Professional.
– Beijing Brown-out to Save Power. BBC News. July 22, 2004.
– Burgos, Nestor P. Jr. (November 7, 2010). Iloilo Power Firms Asked to Explain Brownouts. Philippine Daily Inquirer. Archived from the original on June 5, 2013. Retrieved June 21, 2012. Source: https://en.wikipedia.org/wiki/Brownout_(electricity)
A brownout is a drop in the magnitude of voltage in an electrical power system.
Unintentional brownouts can be caused by excessive electricity demand, severe weather events, or a malfunction or error affecting electrical grid control or monitoring systems. Intentional brownouts are used for load reduction in an emergency, or to prevent a total grid power outage due to high demand. The term brownout comes from the dimming of incandescent lighting when voltage reduces.
In some countries, the term brownout refers not to a drop in voltage but to an intentional or unintentional power outage (or blackout).
