US3246234A

US3246234A - Progressive saturation magnetic amplifier

Info

Publication number: US3246234A
Application number: US208975A
Authority: US
Inventors: Stimler Morton
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-07-10
Filing date: 1962-07-10
Publication date: 1966-04-12
Anticipated expiration: 1983-04-12

Description

April 12, 1966 M. STIMLER PROGRESSIVE SATURATION MAGNETIC AMPLIFIER Filed July 10, 1962 FlG.l.

INVENTOR. MORTON STIMLER United States Patent 3,246,234 PROGRESSIVE SATURATION MAGNETIC AMRLIFIER Morton Stimler, 8308 14th Ave, Hyattsville, Md. Filed July 10, 1962, Ser. No. 208,975 5 Claims. (Cl. 323-6) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a constant current device and more particularly to a magnetic amplifier employing a tapered core for progressive saturation to provide a constant current load circuit.

It was discovered when working with progressive saturation devices that progressive saturation techniques could be advantageously applied to magnetic amplifier circuits. In the particular circuit of this invention a tapered saturable core is saturated to a desired predetermined level. Control windings in the primary and secondary circuits are utilized to shift the saturation level of the tapered saturable core such that a constant current is provided in the load or secondary circuit of the magnetic amplifier.

An object of this invention is to provide a magnetic amplifier having a constant current output characteristic.

Another object of this invention is to provide a constant output current device utilizing progressive saturation techniques.

A further object of this invention is to provide a magnetic amplifier utilizing progressive saturation techniques for regulating current flow in the load circuit of the magnetic amplifier.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. 1 illustrates a circuit of a preferred embodiment of this invention;

FIG. 2 of the drawing illustrates a powdered iron tapered core suitable for use with the present invention; and

FIG. 3 is a sectional view of the powdered iron tapered core of FIG. 2.

Referring now to FIG. 1 of the drawing, in which a schematic diagram of a preferred embodiment of this invention is illustrated, core 11 represented by a progressive saturation symbol has a uniformly varying cross sectional area. The dashed line indicates the degree of saturation which, for example, is approximately one-half of the length of the core shown in FIG. 1. Core 11 is supplied with primary winding 13, control windings 15 and 17 and secondary winding 19. Primary winding 13 is connected to an A.C. voltage source 21. Control winding 15 is connected to a feedback network 23 of the primary circuit. Control winding 17 is connected to the feedback network 25 at the secondary circuit. The windings 15 and 17 are connected in opposition to the winding 13. A load resistor 27 is connected to secondary winding 19 through a portion of feedback network 25.

In operation, under normal conditions, a desired magnitude of current will flow through load resistor 27 as determined by the parameters of the circuit. That is, when core 11 is saturated to a certain level, for example, 50% of the length of the core, an input voltage of a given magnitude applied from A.C. source 21 to primary winding 13 will produce a current flow of a certain magnitude in secondary winding 19 and load resistor 27.

Under these conditions the feedback networks will cause control currents to flow in the control windings and a condition of equilibrium will exist with the core 11 having 50 percent of its length saturated. It is to be noted that (negligible) voltage will be induced in the turns of secondary winding 19 on the saturated portion of the core. That is, one half of the turns of secondary winding 19 will be inactive when core is saturated for 50 percent of its length as indicated in the above conditions.

If a change in the magnitude of the voltage of source 21 should occur, for example if the voltage should increase, increase in voltage will tend to cause an increase in the current flow through primary winding 13 as a result of an increase in voltage across primary winding 13. At the same time there will be an increase in current flow through control winding 15 which will cause an increase in the saturation level of core 11. As core 11 becomes saturated over a greater portion of its length due to this increase in control current in winding 15, an additional number of turns of secondary winding 19 in the newly saturated portion of core 11 will become ineffective, reducing the number of effective turns of winding 19, reducing in turn the voltage developed across secondary winding 19 and hence reducing the current flow through load 27 offsetting the tendency for an increased load current by the increase in voltage across the terminals of primary winding 13. Thus the current fiow through load resistor 27 is kept at a constant value. If the load current actually increased in value, the increased current flow in winding 17 would further saturate core 11, inactivating more of the turns of secondary winding 19 to reduce the current flow through load resistor 17 to the desired design level.

If, on the other hand, the voltage of source 21 should decrease, the tendency for the current through secondary winding 19 and load resistor 27 to decrease will be off- 7 set by the reduction in current fiow through control winding 15 which will decrease the saturation level of core 11 and increase the number of active turns in secondary winding 19. If there should be a decrease in the current fiow through load resistor 27, this reduction in current flow will reduce the current flow in control winding 17 further reducing the saturation level of core 11 and further increasing the number of active turns in secondary winding 19, causing an increase in the voltage drop across winding 19 and an increase current flow through load resistor 27.

Referring now to FIGS. 2 and 3 of the drawing, a tapered core 51 may be utilized in the circuit alternatively into core 11. This core may be made of powdered iron, ferrite or suitable laminated ferromagnetic materials. Square hysteresis loop materials may be employed, if desired.

Whereas

feedback networks

23 and 25 are shown in block diagram, as is well known in the art, these networks may be, for example, transformer couplings. Rectifiers may be included in the bias or feedback circuits to provide a DC. current for bias windings 15 and 17.

Obviously many modifications and variations are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A magnetic amplifier comprising a saturable tapered core, a primary circuit, a secondary circuit, said primary circuit including a primary winding on said core and a first control winding on said core, said secondary circuit including a secondary winding on said core, a second control winding on said core, and a load means, means adapted to connect said primary winding and said first control winding to an A.C. voltage source whereby said amplifier may be energized, means connecting said secondary winding to said load means, said second control winding being connected to said means connecting said secondary winding to said load means, said secondary winding having turns evenly disposed along the length of said core whereby an increase in saturation level of said core decreases the number of effective turns of said secondary winding and a decrease in saturation level of said core increases the number of efiective turns of said secondary winding to decrease or increase the relative voltage induced across said secondary winding respectively, said first and second control windings operative to increase the saturation level of said core when the voltage of said source increases to reduce the efifective turns in said secondary to ofiset said voltage increase, said first and second control windings operative to decrease the saturation level of said core when the voltage of said source decreases to increase the effective turns in said secondary winding to offset said voltage decrease whereby the current in said secondary circuit is maintained at a constant value.

2. A magnetic amplifier having a constant load current comprising a satura-ble core, a primary circuit including a primary winding connectable to an A.C. voltage source, a secondary circuit, said core having a tapered configuration along the full length thereof such that said core may be saturated to any desired portion of the full length of said core. a first bias circuit including a first bias winding and first unidirectional impedance means connecting said first bias winding to said primary circuit whereby a change in voltage of the source will cause a directly proportional change in the saturation level of said core, said secondary circuit including a secondary winding on said core, a load means connected to said secondary winding, a second bias circuit including a second bias winding on said core and second unidirectional impedance means connecting said second bias winding to said secondary circuit whereby a change in the voltage across said secondary winding will cause a directly proportional change in the saturation level of said core, said secondary winding having turns evenly distributed along the full lentgh of said core whereby a change in saturation level of said core will cause an inversely proportional change in the effective number of turns of said secondary winding whereby the current in said load means is maintained at a constant value.

3. A constant output current circuit in a magnetic amplifier comprising a saturable magnetic core, said core having the shape of a truncated cone where-by said core may be progressively saturated to a desired portion of the length thereof, a primary circuit including a primary winding on said core, and means adapted to connect said primary winding to an A.C. voltage source, a secondary circuit including a secondary winding on said core and a load means connected to said secondary winding, a bias circuit including a bias winding on said core, unidirectional impedance means adapted to connect said bias winding to the A.C. voltage source whereby said core will be saturated to a level directly proportional to the magnitude of the voltage applied thereto by the A.C. voltage source, said secondary winding having turns distributed uniformly along the length of said core whereby the number of effective turns in said secondary winding will be inversely proportional to the saturation level of said core and the current in said load means is maintained at a constant level.

4. A constant load current device comprising, a saturable tapered core, an A.C. energizing circuit coupled to said core, a bias circuit including a bias winding on said core, a load circuit including a load winding on said core and load means connected to said load winding, said load winding having turns distributed uniformly along the length of said core whereby a change in the saturation level of said core will cause an inversely proportional change in the efiective number turns of said secondary winding, said bias circuit including unidirectional impedance means connecting said bias winding to said energizing circuit whereby a change in voltage in said energizing circuit will cause a directly proportional change in the saturation level of said core.

5. A constant output current device comprising, a saturable tapered core, an A.C. energizing circuit coupled to said core, a first bias circuit including a first bias wind! ing on said co-re, an output circuit including an output winding on said core and an output load means connected to said output winding, said output winding having turns distributed uniformly along the length of said core where-v by a change in the saturation level of said core will cause an inversely proportional change in the effective number of turns of said output winding, said first bias circuit including first unidirectional impedance means connecting said bias winding to said energizing circuit whereby a change in voltage in said energizing circuit will cause a directly proportional change in the saturation level of said core, a second bias winding on said core, a second unidirectional impedance means connecting said second bias winding to said output circuit whereby a change in voltage across said output winding will cause a directly proportional change in the saturation level of said core.

References Cited by the Examiner UNITED STATES PATENTS Goldner et al. 340--174 Silverman 307-88 De Witz 336- X-Q

Claims

4. A CONSTANT LEAD CURRENT DEVICE COMPRISING, A SATURABLE TAPERED CORE, AN A.C. ENERGIZING CIRCUIT COUPLED TO SAID CORE, A BIAS CIRCUIT INCLUDING A BIAS WINDING ON SAID CORE, A LOAD CIRCUIT INCLUDING A LOAD WINDING ON SAID CORE AND LOAD MEANS CONNECTTED TO SAID LOAD WINDING, SAID LOAD WINDING HAVING TURNS DISTRIBUTED UNIFORMLY ALONG THE LENGTH OF SAID CORE WEHEREBY A CHANGE IN THE SATURATION LEVEL OF SAID CORE WILL CAUSE AN INVERSELY PROKPORTIONAL CHANGE IN THE EFFECTIVE NUMBER TURNS OF SAID SECONDARY WINDING, SAID BIAS CIRCUIT INCLUDING UNIDIRECTIONAL IMPEDANCE MEANS CONNECTING SAID BIAS WINDING TO SAID ENERGIZING CIRCUIT WHEREBY A CHANGE IN VOLTAGE IN SAID ENERGIZING CIRCUIT WILL CAUSE A DIRECTLY PROPORTIONAL CHANGE IN THE SATURATION LEVEL OF SAID CORE.