Constant-voltage transformer
An alternative method is the use of a type of saturating transformer known as ferro resonant transformer or constant-voltage transformer. These transformers use the tank circuit composed of the high-voltage resonant winding and a capacitor to produce a nearly constant average output with a ranging input. The ferroresonant approach is attractive because of its lack of active components, relying on square loop saturation characteristics of tank circuit to absorb variations in the average input voltage. The older designs of ferroresonant transformers had an output with the high harmonic content, leading to distorted output waveform. Modern devices are used to construct a ideal sinewave. The ferroresonant action is a flux limiter instead of a voltage regulator, but with the fixed supply frequency it can sustain an almost constant average output voltage even as the input voltage ranges widely.
The ferroresonant transformers, which are also called as Constant Voltage Transfor mers (CVTs) or ferros, are good surge suppressors, as they give high isolation and inherent short - circuit protection.
A ferroresonant transformer can operate with the input voltage range of ±40% or more of the nominal voltage.
The output power factor remains in range of 0.96 or higher from half to full load.
As it regenerates an output voltage waveform, output distortion, which is less than 4%, is independent of any input voltage distortion, counting notching.
Efficiency at full load is in the range of 89% to 93%. But, at low loads, efficiency can drop below 60% and no load losses can be high as 20%. The current limiting capability also becomes helpless when a CVT is used in an application with the moderate to high inrush current such as motors, transformers or magnets. In this case, CVT has to be sized to accommodate the peak current, hence forcing it to run at the low loads and poor efficiency.
The minimum maintenance is needed. The transformers and capacitors are quite reliable. Some units have included redundant capacitors to permit several capacitors to fail between inspections without any visible effect on the performance of device.
The output voltage varies around 1.2% for every 1per cent change in the supply frequency. For instance, a 2-Hz change in the generator frequency, which is quite large, results in an output voltage change of only 4%, which has less effect for most loads.
It accepts 100 per cent single-phase switch-mode power supply loading without any requirement for derating, including all the neutral components.
Input current distortion remains below 8 per cent THD even when supplying nonlinear loads with over 100 per cent current THD.
Drawbacks of CVTs are their larger size, high heat generation and clear humming sound.
Email based Electronics Devices and circuits assignment help - homework help at Expertsmind
Are you searching Electronics Engineering assignment help expert for help with Constant-voltage transformer questions? Constant-voltage transformer topic is not easier to learn without any external help? We at www.expertsmind.com offers free lecture notes for Electronics Devices and circuits assignment help and Electronics Devices and circuits homework help. Live tutors are available 24x7 hours for helping students in their Constant-voltage transformer related problems. We provide step by step Constant-voltage transformer question's answers with 100% plagiarism free content. We prepare quality content and notes for Constant-voltage transformer topic under Electronics Devices and circuits theory and study material. These are avail for subscribed users and they can get advantages anytime.
Why Expertsmind for assignment help
- Higher degree holder and experienced experts network
- Punctuality and responsibility of work
- Quality solution with 100% plagiarism free answers
- Time on Delivery
- Privacy of information and details
- Excellence in solving electronics engineering questions in excels and word format.
- Best tutoring assistance 24x7 hours