FACILITIES AT SAJAS ELECTRICALS

The quality of any enclosure is dependent largely upon its ability to protect the delicate switchgear and controlgear housed within. To achieve lifetime protection, the enclosure itself has to bear the brunt of environmental forages inflicted by corrosive and dusty atmospheres, acid fumes and extreme temperature and humidity conditions.

At Sajas, we are well aware of these and other factors that tend to drastically reduce the life of expensive control gear and threaten the correct functioning of critical power plant equipment. We have installed a pretreatment and painting system that is comparable with those of the most reputed of control panel manufacturers. We strive to follow the most intricate of technical standards as prescribed by IS Codes in these processes. Our process can be broadly divided into 3 stages, with quality being controlled and assured at each of these stages.

 

1.Pretreatment of Sheet Metal

Our pretreatment system consists of a Seven Tank Cold process. Our tanks are of Mild Steel, coated with a protective lining of FRP. Each tank is 2.5m x 1.5m x 1m in dimension and is more than enough to accommodate the largest single compartments of shells. An overhead crane facilitates handling.

i) Alkaline Degreasing

We use a quality alkali based degreasing chemical for the removal of grease, dirt and other oily matter superficially adhering to CRCA sheets. Quality maintenance of degreasing chemical is carried out on a weekly basis. Degreased sheets are totally free of the mentioned impurities that may otherwise impair the phospating process.

ii) Rinsing

Thorough rinsing is carried out to physically remove dislodged layers of grease.

iii) Acid Derusting

Mill Scales and rust are removed at this stage, employing a chemical based on dilute HCL. Acid strength is frequently monitored by titration. Sludge is removed periodically.

iv) Phosphating

The sheet metal is then dipped in the phosphatising tank to give a phosphate coat of 30 microns as recommended by IS 3618. The thickness is verified using a conel gauge. The Phosphate bath is maintained in accordance with IS 6005 to the prescribed level of free acid content measure by titration; phosphate strength is maintained by starch iodide test.

vi) Rinsing

The sheet metal is again rinsed to remove acid form the metal surface to prevent corrosion of metal.

vii) Phosphating

Zinc passivation is carried out to prescribed standards.

2.PAINTING

i) Sample Tests of incoming raw materials like Zinc Chromate red oxide, Primer, Paint etc., are carried out to ensure quality. The above are tested for

• Viscosity: Ford 4 cup Viscometer is used to ensure proper pigment size.
• Glossiness: Glossometer is used to check gloss factor to be maintained between 40% and 60% reflectivity.
• Shade: Shade is checked visually using shade card as per IS 5.

 

ii) Painting

a)Painting is carried out in custom built bullows type painting booth. The water wall and induced draft facilitate the removal of unwanted secondary paint. The closed environment ensures a dust free atmosphere. Spray gun and compressor of optimum rating are used to suit paint pigment size.

A coating of Zinc Chromate red oxide is followed by an epoxy based undercoat and two epoxy based corrosion resistant finishing coats. The total paint thickness is ensure at 100-150 microns using Conel gauge.

b) Powder Coating

A powder coating shop suitable to powder coat enclosures of varying dimensions from the smallest of Junction boxes to the largest of MCCs.

Imported Electrostatic high voltage gun along with Twin Cyclone Powder recovery system and high energy baking oven ensure satin smooth finish hitherto appreciated in imported enclosures. A wide range of powder shades are possible with gloss and finish as per customer requirement

iii) Baking

Baking is done in an oven equipped with imported infrared heaters with tight control of temperature, using dual thermocouple and high efficiency impeller.

iv) Plastipeel

After baking, a double coat of Plastipeel is sprayed on the panel to protect the painted surface from dust, dirt and scratches that might inevitably appear on the surface during assembly.