CRGO / CRNO Coil
CRGO (Cold Rolled Grain Oriented) and CRNO (Cold Rolled Non-Oriented) coils are essential electrical steels used in transformer cores and other electrical equipment.
CRNO steel has thicker laminations (typically 0.50mm or more) and results in higher core losses compared to CRGO. On the other hand, CRGO offers thinner laminations (0.23mm, 0.27mm, 0.30mm, 0.35mm – commonly known as M3, M4, M5 & M6) and is widely preferred for distribution transformers due to its superior magnetic properties and mechanical elasticity in the rolling direction.
“CRGO steel ensures high efficiency, reduced losses, and long-lasting performance in transformer cores.”
Technical Team, JAAS Steel Pvt. Ltd.
Key Features
Why CRGO / CRNO Coils are vital for transformer applications:
- High Magnetic Permeability
- Reduced Core Losses
- Available in multiple grades (M3, M4, M5, M6)
- Long-Term Durability
CRGO coils are the preferred choice for energy-efficient transformers, while CRNO finds usage in motors, generators, and appliances where efficiency requirements are moderate.
Working Process
Our streamlined process ensures reliability and top performance:
Raw Material Inward
Material: CRGO coils are received from approved suppliers.
Checks: Visual inspection, test certificate verification (core loss, thickness, grade).
Storage: Coils stored in clean, dry area to prevent rust or damage.
RM Selection as per requirement.
Slitting Process
Purpose: To slit wide CRGO coils into narrow strips as per lamination width requirement.
Process: Coil loaded on decoiler → passed through slitting cutter for precise width cutting → rewound into slit coils.
Quality Checks: Width accuracy, burr level, edge quality.
Cutting Process
Purpose: To cut slit strips into required lamination lengths and shapes.
Process: Slit coil fed to cut-to-length or step-lap cutting machine. Pieces cut as per design with proper step-lap or butt-lap.
Checks: Length tolerance, burr, step accuracy, orientation marking.
Note: For certain designs, holes, slots, or notches are punched to aid assembly and clamping.
Core Assembly
Purpose: To assemble laminations into complete transformer cores.
Process: Laminations are stacked layer by layer as per core design (step-lap configuration). Tightening bolts or frames applied to ensure proper compression.
Checks: Dimension accuracy, stacking factor, loss test (NLL), insulation intactness.
Testing & Inspection
Core Loss & Magnetic Flux Density measured using Epstein
Dimensional, burr, and insulation checks done.
Results recorded and verified against specifications.
Packing & Dispatch
Laminations packed in moisture-proof wrapping on wooden pallet.
Proper labeling with grade, lot no., dimensions, and weight.
Dispatched to transformer manufacturers or customers.
Purpose
To produce precision CRGO laminations with minimal core loss, accurate dimensions, and consistent quality for use in power and distribution transformer cores.
Applications
CRGO and CRNO coils are widely used in distribution transformers, power transformers, generators, electric motors, and industrial equipment, delivering efficiency and durability in diverse electrical applications.
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