Starting and operating ballast for high pressure sodium lamps

• US 3,889,152 A
• Filed: 10/10/1974
• Issued: 06/10/1975
• Est. Priority Date: 10/10/1974
• Status: Expired due to Term

• Current Assignee: Magnetek Incorporated (Columbus Mckinnon Corporation)
• Original Assignee: Marion Rosiak, Richard Hill Jr. Bodine
• Inventors: Bodine, Richard Hill Jr., Rosiak, Marion
• Primary Examiner(s): Rolinec, R. V.
• Assistant Examiner(s): La Roche, E. R.
• Application Number:
  US05/513,711
• Time in Patent Office: 243 Days
• Field of Search: 315/194,199,2R,205,206,208,29R,245,276,279,DIG.2,DIG.5
• US Class Current: 315/205
• CPC Class Codes: H05B 41/042 using semiconductor devices
• CPC Class Codes: Y10S 315/02 High frequency starting operation for fluorescent lamp
• CPC Class Codes: Y10S 315/05 Starting and operating circuit for fluorescent lamp

Abstract

A ballast for starting and operating a high intensity discharge type lamp is disclosed which incorporates electronic switching elements in one form. The apparatus includes a winding on a magnetic core having at least one tap. A lamp is adapted for connection to the output of the winding and a series circuit of a resistor and a capacitor are connected in parallel of the lamp. A capacitor are connected in parallel of the lamp. A capacitor and a semiconductor control rectifier are connected in series to the tap and diode is connected in shunt of the semiconductor controlled rectifier poled oppositely thereto. A diac is connected to the first capacitor and to the gate electrode of said semiconductor controlled rectifier for triggering the controlled rectifier when the voltage on the capacitor reaches a predetermined level. Suitably the resistor and capacitor circuit is adjusted so that the desired triggering level occurs when the instantaneous AC voltage is at or near a peak level.

Claims

1. Means for starting and operating an arc discharge lamp comprising:

inductive ballast means, said ballast means containing a magnetic core and at least a first winding of N turns of insulated wire mounted on said core;

tap means on said winding at a position approximately NT turns from said first end of said winding, wherein N-NT/NT is a quantity greater than 1;

a circuit common;

means for connecting said lamp means in an electrical series circuit between an end of said winding and said circuit common;

means for monitoring the instantaneous voltage across said first winding, said means comprising;

first resistor;

first capacitor;

means connecting said first resistor and first capacitor means in electrical series circuit between said winding end and said circuit common;

second capacitor means;

first and second semiconductor controlled rectifier means, each of said rectifier means containing an anode, a cathode and a gate electrode;

means connecting the anode of one controlled rectifier means to the cathode of the other controlled rectifier means to form a series circuit and means connecting said second capacitor means in series with said aforementioned series circuit between said tap and said circuit common;

diode rectifier means, said diode rectifier means being connected in shunt of said series circuit of said controlled rectifier means and in opposite polarity thereto;

second and third resistor means connected electrically in series across said diode rectifier means;

means placing the midpoint of said series resistor circuit electrically in common with a point in circuit between said series connected controlled rectifier means;

fourth resistor means connected between said gate electrode of said first controlled rectifier means and said cathode thereof;

fifth resistor means connected between the gate electrode of said second controlled rectifier means and said common lead;

third capacitor means connected between said gate electrode of said first controlled rectifier and said common lead; and

diac means connected between the gate electrode of said second controlled rectifier to said capacitor of said voltage monitoring circuit.

2. Apparatus for starting and operating an arc discharge lamp having a starting peak voltage V1 and a normal operating voltage V2, where V1>

V2, from a source of AC voltage having a half cycle time period of T seconds, comprising;

electrical ballast means for presenting an electrical impedance to AC voltage, said ballast means including;

a core of magnetic material;

at least oNe winding located on said core, said winding comprising a predetermined plurality of turns of insulated electrical wire between a first and second winding end; and

tap means on said winding located at a predetermined number of turns NT from said first winding end for dividing said winding into two winding portions, one portion being larger than the other portion, whereby the turns in said larger portion bears a ratio to the turns in said smaller portion, N-NT/NT, of greater than 1;

arc discharge lamp means having first and second terminals;

a circuit common of reference zero potential;

means for connecting said second winding end in circuit with said first lamp terminal and means for connecting said second lamp terminal in circuit with said circuit common to place said winding and lamp in a series current conducting circuit;

means for coupling AC voltages from an AC source into said one winding to provide an AC voltage V2 at said second winding end when said lamp is in a current conducting state and an AC voltage, V3, when said lamp is not in the current conducting state, where V1>

V3>

V2, and to provide an AC voltage at said tap means;

first resistor means;

first capacitor means;

means connecting said first resistor means and said first capacitor means in electrical series circuit and means for connecting said electrical series circuit in circuit between said second winding end and said circuit common;

unidirectional current conducting semiconductor controlled rectifier means having a positive polarity anode, a negative polarity cathode, and a gate electrode and having the characteristic of normally being in a noncurrent conducting state until triggered by a proper voltage at said gate electrode and thereupon conducting current only in a direction from its anode to its cathode, regardless of the maintenance of the proper voltage at said gate electrode, until such current reduces to zero and thereupon restoring to its non-current conducting state;

unidirectional current diode rectifier means having a positive polarity terminal and a negative polarity terminal for conducting current therethrough only in a direction from its positive to negative terminals;

second capacitor means;

means connecting said second capacitor means and said semiconductor controlled rectifier means in a series current conducting circuit, including the anode and cathode thereof, and means locating said series circuit in circuit between said tap means and said circuit common;

means connecting said diode rectifier means in circuit across said controlled rectifier means and with said diode means being poled in a direction opposite in polarity to the polarity of the respective controlled rectifier terminals so that said rectifier means conducts current only in a direction opposite to the direction of current conducted by said controlled rectifier means;

diac semiconductor switch means responsive to a voltage of a predetermined level, V4, across its terminals for switching from a noncurrent conducting state to a current conducting state;

second resistor means;

means connecting said diac means and said second resistor means electrically in a series circuit with one end of said diac connected in circuit between said first resistor and first capacitor and with one end of said second resistor connected to said circuit common; and

means connecting the gate electrode of said controlled rectifier means electrically in circuit between said diac switch means and said second resistor means, whereby responsive to said first capacitor charging to a voltage level, V4, said diac switches into a current conducting condition and applies a proper voltage from said capacitor to said gate electrode to trigger said controlled rectifier means into its current conducting state;

said first resistance means and said first capacitance means being sized such that at said AC voltage, V3, applied to said first lamp terminal said first capacitor means is charged through said first resistor means to said voltage V4 within a time period of less than one-half cycle of AC and more than one-eighth cycle of AC but insufficient to attain said voltage V4 when the AC voltage at said first lamp terminal is of a level of V2 or less.

3. The invention as defined in claim 2 wherein said means for coupling AC voltages from an AC source into said winding comprises:

first electrical lead means connected in circuit with said first winding end in said electrical series circuit for connection to one terminal of said AC voltage source;

second electrical lead means connected in circuit with said circuit common for connection to the second terminal of said AC voltage source wherein said AC source is placed in series with said winding.

4. The invention as defined in claim 2 wherein said means for coupling AC voltages from an AC voltage source into said winding comprises a primary winding located on said core adapted for coupling to said AC voltage source.

5. The invention as defined in claim 2 wherein said means for coupling AC voltages from an AC source into said winding comprises:

an auto-transformer having a primary winding and a secondary winding with said primary winding being adapted for connection to said AC voltage source, and wherein said secondary winding is connected in said electrical series circuit with said first winding end and the other end of said secondary winding is connected in circuit with said circuit common.

6. Apparatus for starting a gaseous discharge lamp having at least two electric terminals which form part of a current conducting circuit through said lamp from an alternating current source in combination with lamp ballast means for supplying operating voltages to said lamp, said lamp ballast means of the type which includes at least a winding, means for coupling said winding to said AC source, first electrical lead means for connection in circuit with one terminal of said lamp, second electrical lead means for connection in circuit with the other terminal of said lamp, and third electrical lead means coupled in circuit to said winding at a predetermined number of turns from an end thereof, comprising the combination of:

first resistor means;

first capacitor means;

means connecting said first resistor means and said first capacitor means in electrical series circuit and means for connecting said electrical series circuit in circuit between said first and second lead means;

semiconductor controlled rectifier means having a positive polarity anode, a negative polarity cathode, and a gate electrode, said controlled rectifier means having the characteristic of normally being in a noncurrent-conducting state until triggered by a proper voltage at said gate electrode and thereupon conducting current only in a direction from its anode to its cathode regardless of the continuance of said proper voltage at said gate electrode, and such current reduces to zero and thereupon restoring to its noncurrent-conducting state;

diode rectifier means having a positive polarity terminal and a negative polarity terminal for conducting current therethrough only in a direction from its positive to its negative terminals;

second capacitor means;

means connecting said second capacitor means and said semiconductor controlled rectifier means in a series current-conducting circuit, including the anode and cathode thereof and means for coupling said series circuit between said third lead means and one of said first lead means and second lead means;

means connecting said diode rectifier in circuit across said controlled rectifier means with said diode means being poled in a direction opposite in polarity to the polarity of the respective controlled rectifier means so that said rectifier means conducts current only in a Direction opposite to the direction of current conducted by said controlled rectifier means;

diac semiconductor switch means responsive to a predetermined voltage across its terminals for switching from a noncurrent-conducting state to a current conducting state;

second resistor means;

means connecting said diac switch means and said second resistor means electrically in a series circuit with one end of said diac connected in circuit between said first resistor and said first capacitor for applying voltage on said capacitor to said diac switch means and with one end of said second resistor means connected in common with the cathode of said controlled rectifier means; and

means connecting the gate electrode of said controlled rectifier means electrically in circuit between said diac means and said second resistor means.

7. The invention as defined in claim 6 further comprising:

a second semiconductor controlled rectifier means having a positive polarity anode, a negative polarity cathode and a gate electrode;

means connecting said second semiconductor controlled rectifier means in series circuit between said first semiconductor controlled rectifier means and said second capacitor means, and with said diode rectifier means connected across the series combination of both of said controlled rectifier means;

third and fourth resistor means of approximately equal resistance levels;

means connecting said third resistor means in circuit between the anode and cathode of said second controlled rectifier means and means connecting said fourth resistor means in circuit between the anode and cathode of said first resistor means;

fifth resistor means connected between said gate electrode of said second controlled rectifier means and said anode thereof;

third capacitor means connected between said gate electrode of said second controlled rectifier means and said anode of said first controlled rectifier means.