Tap converter
Encyclopedia
The tap converter is a variation on the cycloconverter
, invented in 1981 by New York City electrical engineer Melvin Sandler and perfected in 1982 through 1984 by graduate students Mariusz Wrzesniewski, Bruce David Wilner, and Eddie Fung.
Whereas the cycloconverter
switches among a variety of staggered input phases to piece together an extremely jagged output signal, the tap converter synthesizes a much smoother signal by switching among a variety of (obviously synchronized) transformer output taps. Both linear spacing and power-of-two-style Vernier spacing can be employed in establishing the tap positions, e.g., a four-tap transformer can provide taps at 0.25, 0.5, 0.75, 1.0 (linear) or 0.0625, 0.125, 0.25, and 0.5 (Vernier). (The limitations of the Vernier—in this case, that the maximum obtainable amplitude is 0.9375—are less discernible as more taps are added.) Employing a Scott
transformer
input connection in order to provide a quadrature phase, an even smoother output waveform can be obtained. Prototypes of the device were constructed and field-tested under a variety of conditions—nominally as a VSCF power source for military aircraft—and ornate computer models were constructed for exploring more ornery considerations, such as flux leakage, hysteresis, and practical thyristor
characteristics. All of this work was performed at New York's Cooper Union for the Advancement of Science and Art.
As of 2007, the tap converter remains uncommercialized but is used in several military applications due to the minimal output harmonics.
Cycloconverter
A cycloconverter or a cycloinverter converts an AC waveform, such as the mains supply, to another AC waveform of a lower frequency, synthesizing the output waveform from segments of the AC supply without an intermediate direct-current link . They are most commonly used in three-phase...
, invented in 1981 by New York City electrical engineer Melvin Sandler and perfected in 1982 through 1984 by graduate students Mariusz Wrzesniewski, Bruce David Wilner, and Eddie Fung.
Whereas the cycloconverter
Cycloconverter
A cycloconverter or a cycloinverter converts an AC waveform, such as the mains supply, to another AC waveform of a lower frequency, synthesizing the output waveform from segments of the AC supply without an intermediate direct-current link . They are most commonly used in three-phase...
switches among a variety of staggered input phases to piece together an extremely jagged output signal, the tap converter synthesizes a much smoother signal by switching among a variety of (obviously synchronized) transformer output taps. Both linear spacing and power-of-two-style Vernier spacing can be employed in establishing the tap positions, e.g., a four-tap transformer can provide taps at 0.25, 0.5, 0.75, 1.0 (linear) or 0.0625, 0.125, 0.25, and 0.5 (Vernier). (The limitations of the Vernier—in this case, that the maximum obtainable amplitude is 0.9375—are less discernible as more taps are added.) Employing a Scott
Scott-T transformer
A Scott-T transformer is a type of circuit used to derive two-phase current from a three-phase source or vice-versa. The Scott connection evenly distributes a balanced load between the phases of the source....
transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
input connection in order to provide a quadrature phase, an even smoother output waveform can be obtained. Prototypes of the device were constructed and field-tested under a variety of conditions—nominally as a VSCF power source for military aircraft—and ornate computer models were constructed for exploring more ornery considerations, such as flux leakage, hysteresis, and practical thyristor
Thyristor
A thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased .Some sources define silicon controlled rectifiers and...
characteristics. All of this work was performed at New York's Cooper Union for the Advancement of Science and Art.
As of 2007, the tap converter remains uncommercialized but is used in several military applications due to the minimal output harmonics.