General Electric Co., the nation's ninth-largest industrial concern, reported yesterday that earnings in the final quarter of 1980 rose 7.3 percent from the same 1979 period. Westinghouse Electric Corp., ranked 37th, reported a 1 percent increase in profits in the same period.

GE, a diversified producer of electrical equipment, cited improved returns from operations in each of its business segments and reported a 7 percent increase in profits for all of 1980 compared with 1979.

Westinghouse, also a major producer of electrical equipment, said 1980 earnings rose 21.7 percent from the previous year, despite the sluggish economy, with help from products related to defense, energy and service.

GE's earnings in the fourth quarter were $411 million ($1.80 a share) on sales of $6.92 billion, compared with earnings of $383 million ($1.68) on sales of $6.13 billion in the final three months of 1979.

For the entire year, GE said earnings rose to $1.51 billion ($6.65) on sales of $25 billion. That compared with earnings of $1.41 billion ($6.20) on sales of $22.46 billion a year earlier.

GE Chairman Reginald Jones said revenues and operating margins for each segment of the Fairfield, Conn.-based company were higher in 1980 than in 1979. Jones said capital spending in 1980 was a record $1.93 billion, up 53.2 percent from 1979.

GE products include consumer goods, jet engines, missile and radar systems, plastics and medical products. It also mines coal, iron ore, uranium and copper.

Westinghouse said that in the fourth quarter of 1980 it earned $106.9 million ($1.25 a share) on sales of $2.26 billion. Those results were better than the operating income of $105.95 million ($1.24) on sales of $2.07 billion reported for the final quarter of the previous year. Fourth-quarter results in 1979 were affected by $222.86 million in extraordinary losses related to uranium litigation, which produced a net loss of $116.9 million in that period.

In 1980, Westinghouse reported earnings of $402.88 million ($4.71) on sales of $8.5 billion compared with operating income of $331.07 million ($3.85) on sales of $7.44 billion. Results in 1979 were affected by a seven-week strike and extraordinary losses of $405 million related to the settlement of uranium litigation, resulting in a $73.93 million net loss that year.

"On balance, the 1980 results were good despite the difficult economic conditions that prevailed throughout the year," said Westinghouse Chairman Robert Kirby.

Westinghouse makes electrical and mechanical equipment, designs and equips nuclear power plants, and owns and operates five television and seven radio stations.

Minnesota Mining and Manufacturing Co., a broad-based company best known for its Scotch brand tape products, yesterday reported that earnings rose slightly in the 1980 fourth quarter and the entire year despite rising prices for raw materials, particularly silver.

Preliminary results showed a $174.4 million profit for the quarter ended Dec. 31, up 4.3 percent from $167.2 million in the year-earlier period. Per-share earnings rose to $1.49 a share from $1.43 in the 1979 quarter.

The company said worldwide sales for the fourth quarter totaled $1.506 billion, a 10.1 percent increase from $1.367 billion in the same period a year ago.

Earnings for the full year were $678 million ($5.78 a share) up 3.5 percent from $655.2 million ($5.59) in 1979. Sales for the full year grew 11.7 percent to $6.080 billion from $5.44 billion a year earlier, 3M said.

Lewis W. Lehr, 3M's chairman and chief executive officer, called 1980 a challenging year, citing inflation in costs and sluggish economic conditions in particular.

The Caterpillar Tractor Co., a leading maker of construction machinery, says earnings in the final quartr of last year soared 442 percent from the same period a year ago, when the company was hit by an 11-week strike.

Caterpillar said Wednesday that it earned $143.2 million ($1.65 a share) on sales of $2.1 billion in the final three months of 1980. That compared with earnings of $26.4 million (31 cents) on sales of $1.32 billion in the strike-plagued final quarter of 1979.

Earnings for all of 1980 totaled $564.8 million ($6.53) on sales of $8.6 billion, up from earnings of $491.6 million ($5.69) on sales of $7.61 billion a year earlier.

The company said the increased sales receipts mostly reflected the impact of inflation on prices. Physical sales volume was approximately the same both years, Caterpillar added.

Pfizer Inc., the pharmaceutical house, earned $3.45 a share last year, up from $3.26 in 1979, on a rise in sales to $3.029 billion from $2.746 billion.

Net income rose to $254.8 million from $237.9 million.

Final quarter net was $64.5 million (88 cents a share) on sales of $825.3 million, up from $58.6 million (80 cents) a year earlier on sales of $743.8 million.