Thursday, January 7, 2010

Magnetic Ballasts Project Report

Magnetic Ballasts {Open Type Vacuum Pressure Impregnated Technology}

Require Raw Materials: ---
1. Laminations “U” & “T”
2. Enameled Copper Wire
3. Base Plate
4. Terminal Connector
5. Bare Copper or Insulation board paper
6. Plastic Paper
7. Sleeves
8. Cellophone Tape
9. Baking type white varnish
10. Stoving Paint & Thinner OR Powder-coating Powder

Required Machinery: ---
1. C.N.C Coil Winding Machine
2. High Voltage Testing Machine
3. Ammeter Voltmeter & Wattmeter Display Unit
4. Crimping Machine
5. Heating Oven
6. Vacuum Impregnation Unit
7. Painting Booth & Spray Gun OR Powder Coating Unit

These Ballasts are made by using latest Vacuum Pressure Impregnated Technology that ensures to generate low operating temperature there by resulting in saving of electrical power consumption by about 10 to 12 watts per Tube-light per running hour. Since it is an open type construction of the choke, it helps in faster heat dissipation and reduces the iron losses. These ballasts are also available with low loss design. The complete technical know-how to design is briefed here.


Ballasts are wound using electrolytic grade enameled copper wires POLYSTERMIDE (P.I.E.) 180° 'H'CLASS of appropriate cross-section (See Annexure 1), ensuring lower losses and low temperature rise. The wire is wound on an aluminum mandrel with respect to their wattage and stack length. The wound wire is wrapped in to a plastic sheet using transparent cello phone tape. The end terminals are scraped using 100 no. sand paper to ensure that the enamel on its surface is removed, so that it can be easily soldered to the eyelids. After scarping the sleeves are inserted into both the wire ends.


High quality Silicon (Cold Rolled Non-Grain Oriented) Steel and Electro Galvanized Cold Rolled Steel lamination core is used for ballast. By using Silicon steel of grade M-45 and M-47 {ASTM} (see annexure 2) the ballasts loss of 8 W i.e., 3 Star or C type in EEI can be achieved and for low loss M 27 and M36 grade of Silicon steel is used. Electro Galvanized Cold Rolled Steel is used for ballasts of loss more than 8W falling in 2 Star and 1 Star category. The Ballasts Laminations are of “U” and “T” type with dimension of 40mm X 30.5mm for 9,11,13,18/20 & 36/40 wattage ballasts. The laminations should be burr free and with good insulation to avoid humming and reduce eddy current loss respectively.


The plastic end caps (Glass filled Nylon material) one with eyelid hold and the other without are fixed to the both ends of the wound enamel copper wire. Firstly “T” laminations are inserted in to the wound copper and then air gap (bare copper or Insulation board paper) is placed at the point of intersection of “U” and “T” lamination assembly. The air gap wire has to cover the “T” lamination length wise from one end to the other to ensure a correct current setting. Now from the opposite direction the “U” core is inserted. The core is inserted tightly without gaps in between laminations to avoid humming and vibration in the ballasts. But forceful inserting of laminations may cause damage to the enamel of the wire and fail at the high voltage testing, hence care should be taken not to force the laminations. After the assembly the two scrapped end wire with sleeves are twisted to the eyelid hold provided in one of the plastic end cap. The eyelid are pushed into the eyelid hold with copper wire and crimped using a small crimping tool. The eyelid that is crimped is soldered using a soldering pot. These assembled core coils combinations are the crimped on to the base plate {Mild Steel plate of 0.8 or 1 mm thick} using a crimping machine. The crimped core coil assembly is tested for any short wire and loss of enamel using a High Voltage testing machine of 2KW capacity. It is very important to see that the terminals of the High Voltage testing machine touches both crimped terminals only. The high voltage failed units are separated and rework is done on them. The crimped core coil assembly is tapped at the bottom using small hammer or a mallet to get the prescribed current setting on the testing machine (Delta make Current Voltage and Wattage indicator}. The core coil assembly with correct current setting is now ready for vacuum impregnation.

Vacuum Impregnation:

The baking type white varnish with Thermal class of Insulation Class H or Class F is used for vacuum impregnation. The core coil assembly is neatly pilled in the top booth of the impregnation plant and the varnish is pumped from the other booth. The varnish is filled such that the core coil assembly is completely immersed, the core coil assembly is left in the booth for about 10 minutes and the temperature is maintained at 60 degrees centigrade. Then varnish is drained back to the bottom booth and vacuum is created using the vacuum pump in the booth, which contains the core coil assembly. After all the white varnish drips out of the core coil assembly (about 15 minutes), the core and coil assembly is shifted to the preheated oven. The core and coils are placed in the preheated oven where the temperature is maintained at 120 degree centigrade. The white varnish on the core and coils are dried in this oven by about 15 minutes time. After the core and coil assembly are cooled the extra protruding dried white varnish is cleaned using a blade and it is noted that the all the four surface of the core and coil assembly is smooth without any extra dried varnish mainly on the top surface on which the brand name has to be printed.

Painting or Powder Coating:

The cleaned core and coils are either painted or powder-coated depending on the requirement. The process for painting and powder coating has a slight change.
For painting, the core and coil assembly is directly spray painted with bake able stoving paint (“GEM” brand stoving paint) to which is added a good quality quick drying thinner (“DUCO” brand thinner) used in automobile painting. Core and coils are painted in a spray booth with the help of a spray gun normally used in automobile painting. The painted ballasts are then dried in an oven. The temperature is maintained at 105 degree centigrade for about an hour.
For powder-coating, the core and coil assembly are placed on a tray (36 core and coil assembly in 6 x 6 row and column) in a pre-heated oven maintained at 70 degree centigrade for about 5 minutes (this is done so that the powder sticks to the both plastic caps, which cannot be electro charged) and then the core and coil assembly are powder-coated using white powder-coating powder of low curing temperature of 150 degree centigrade. A thin layer of powder is sprayed from the powder-coating gun on all the sides of the core and coil assembly. The spray is inspected to have evenly spread on to the surface without any lumps or null powder spots. The powder-coated ballasts are then dried in an oven. The temperature is maintained at 160 degree centigrade for about an hour.

Terminals Connector:

Terminal plates with Brass terminals for higher current capacity are used. Terminal Blocks with screw on well-insulated contacts are connected.

Brand Name Printing:

The Ballasts are now branded using their brand name screen print board or a pad-printing machine.


The Branded Ballasts are packed in polytene covers and are put in a specially made cartoon single individual boxes. These individual packed Ballasts are then packed in a lot of 25 nos in a big cartoon box and are ready for dispatch.

For Raw Material supply and other guidence

Contact :

Mr. Manoj Kumar
Yashaswini Transcores
Bangalore - 78.
Ph : +91-9844043104.