Saturable-Core Reactor
Saturable-Core Reactor (Saturable Reactor)
I. Description
A saturable reactor in electrical engineering is a special form of inductor where the magnetic core can be deliberately saturated by a direct electric current in a control winding. Once saturated, the inductance of the saturable reactor drops dramatically. This decreases inductive reactance and allows increased flow of the AC current.
II. Function/Operation
Figure 1.
This scheme controls the output voltage by varying the impedance of a saturable reactor as shown in diagram. This scheme is simple in concept and has a good line transient rejection. The drawbacks of this technique include slow response (10 cycles), high output impedance which gives high distortion with non-linear loads such as adjustable speed drives, sensitive to load power factor, will not handle surge currents such as motor starting and will not suppress transients generated inside plant. the saturable reactor. The saturable reactor is an electro-magnetic "switch". This switch controls current flow to the load by "switching" in and out of saturation during each half cycle. The resulting current waveform is rich in harmonics. Referring back to Figure 1, the switch represents the AC coils and core of the saturable core reactor. The switch control represents the DC coil and DC drive circuitry used to saturate the core. The amount of current to the load is controlled by controlling the amount of DC current applied to the DC coil which in turn controls the amount of saturation in the core.
Typical input voltage and current waveforms for a saturable core reactor power supply, with the core partially saturated, is shown in the oscilloscope picture of Fig. 2b. When the core is fully saturated the current waveform is near sinusoidal. The inherent series reactance of a saturable reactor causes a phase shift between the voltage and current. Fig. 2b shows the voltage leading the current. Due to the series reactance, the best
I. Description
A saturable reactor in electrical engineering is a special form of inductor where the magnetic core can be deliberately saturated by a direct electric current in a control winding. Once saturated, the inductance of the saturable reactor drops dramatically. This decreases inductive reactance and allows increased flow of the AC current.
II. Function/Operation
Figure 1.
This scheme controls the output voltage by varying the impedance of a saturable reactor as shown in diagram. This scheme is simple in concept and has a good line transient rejection. The drawbacks of this technique include slow response (10 cycles), high output impedance which gives high distortion with non-linear loads such as adjustable speed drives, sensitive to load power factor, will not handle surge currents such as motor starting and will not suppress transients generated inside plant. the saturable reactor. The saturable reactor is an electro-magnetic "switch". This switch controls current flow to the load by "switching" in and out of saturation during each half cycle. The resulting current waveform is rich in harmonics. Referring back to Figure 1, the switch represents the AC coils and core of the saturable core reactor. The switch control represents the DC coil and DC drive circuitry used to saturate the core. The amount of current to the load is controlled by controlling the amount of DC current applied to the DC coil which in turn controls the amount of saturation in the core.
Typical input voltage and current waveforms for a saturable core reactor power supply, with the core partially saturated, is shown in the oscilloscope picture of Fig. 2b. When the core is fully saturated the current waveform is near sinusoidal. The inherent series reactance of a saturable reactor causes a phase shift between the voltage and current. Fig. 2b shows the voltage leading the current. Due to the series reactance, the best
References: http://en.wikipedia.org/wiki/Saturable_reactor McGraw-Hill Science & Technology Dictionary http://www.sigmaelectricals.com/autotech01.htm ://www.docstoc.com/docs/49458695/Saturable-Reactor---Patent-5636113