ANSI NEMA C82.3 pdf free download
ANSI NEMA C82.3 pdf free download.Electric Lamps一 Reference Ballasts for Fluorescent Lamps.
5 Design characteristics
5.1 General design for line frequency reference ballasts
A line frequency reference ballast is a self-inductive coil, with or without an additional series resistor for power factor adjustment, designed to give the operating characteristics of Clause 6.
It may be used either in a circuit employing a starter or, where applicable, in a circuit including separate power sources to heat the lamp cathodes. Further details of those circuits are given in ANSI C78.375.
5.2 General design for high-frequency reference ballasts at 25 kHz
A high-frequency reference ballast is a resistor or choke-coil designed to give the operating
characteristics of Clause 7.
5.3 Permanence of impedance
5.3.1 Fixed-impedance type ballasts
Since this type of reference ballast is intended to serve as a permanent baseline of reference. it is vitally important that the ballast is constructed as to provide permanence of impedance under normal conditions of use and abuse.
A recheck of the impedance of the ballast shall give values within 0.1% of those previously determined.
5.3.2 Adjustable-impedance type ballasts.
This type of reference ballast, when adjusted to any given value of impedance, shall be capable of holding that adjustment through normal periods of use. For this purpose, suitable means shall be provided for mechanically locking the movable core (or other movable parts) in any desired position.
5.4 Enclosure
A reference ballast shall be enclosed for mechanical protection. In the case of the adjustable-impedance- type ballast, the series resistor need not be in the same enclosure with the reactor. Care should be taken for proper conduction of the dissipated wattage losses.
5.5 Magnetic shielding (for 60 Hz reference ballast)
A reference ballast should be protected against magnetic influence in such a way that its impedance at reference current shall not be changed by more than 0.2% when a half-inch (13-mm) plate of magnetic steel is placed within 1 inch (25 mm) of any face of the ballast enclosure. The steel plate shall have dimensions at least 2 inches (51 mm) greater than the maximum dimension of the ballast enclosure and shall be placed in geometric symmetry to each surface as tested. In the event that a reference ballast is not magnetically shielded, precautions shall be taken to keep magnetic objects far enough removed from the leakage field so that the impedance of the ballast will not be altered by more than the 0.2% mentioned above.
5.6 Inclusion of instrument current coils
When an adjustable-impedance type reference ballast is being used, a choice may be made as to whether the impedances of the instrument current coils (the ammeter and wattmeter) will or will not be included as part of the impedance of the reference ballast. Either procedure is satisfactory, however if the coils are included in the original calibration they must be left in the circuit at all times during subsequent use. Figure 1 shows the current coils included.
ANSI NEMA C82.3 pdf download.
