19-09-2010, 12:43 PM
Buck–boost transformer
It is a type of autotransformer mainly used to make small adjustments to the voltage applied to alternating current equipment.The UPS for computers, electric power distribution, the tanning bed in industries all make use of this equipment. a two-winding transformer is used whaen large adjustments in the voltage are required.
Types
self adjusting and passive designs are the two major types of buck-boost transfromers. In the active types, the input voltage is continuously monitored and the outgoing voltage is adjusted to be within an acceptable range.If a variance is sensed in the incoming voltage, it will either buck or boost (ie lower or raise ) the voltage. To allow adjustment of the ratio, several taps are provided in the transformer. A control circuit selects which tap to use .
Passive ones are used where the amount of buck or boost is fixed. For example, when a 230 VAC to a 208 V device is connected, a particular amount of boost would be used.
Consumer and business applications
tanning market used Fixed transformers. hey have factory-installed plugs and connections and the need for hard-wiring small loads is eliminated. they are rated in load amps (A) to make it easier for the end users to select.
Electric power distribution applications
voltage drop in power lines occur due to slight resistance of the metallic conductor. large boost transformers are placed on poles in remote arear inorder to bring the voltage back up to acceptable levels. But it takes away some amperage capacity.
for more details, visit these pages:
http://en.wikipediawiki/Buck%E2%80%93boost_transformer
http://buckboosttransformer
http://nrgsystemsFileLibrar/5bff08e2113c4001973e0f5568687
http://conceptorgtechlibrary/PowerTechnology/Buck-N-Boost_Xfmrs.pdf