Westinghouse Electric Corp. announced yesterday net income jumped to $91.4 million ($1.06 a share) on sales of $2 billion during the third quarter.

Net income for the same period in 1979 was $50.9 million (59 cents) on sales of $1.6 billion. The figures were before extraordinary uranium losses that reduced not income to 44 cents a share. A seven-week strike also reduced the 1979 earnings.

Chairman Robert E. Kirby said the improved results were from Westinghouse's three major operating companies and its broadcasting subsidiary.

"Continued strong performance in many segments of the corporation -- particularly those related to defense and service businesses -- offset softness in product lines which are sensitive to current national economic conditions," he said.

He said he expected fourth-quarter results to show improvement over the quarter that just ended.

For the first nine months of this year, Westinghouse had net income of $295.9 million ($3.46) on sales of $6.2 billion.

During the same period in 1979, the company's income before the uranium losses was $225 million ($2.61) on sales of $5.3 billion.After the extraordinary losses, the new income during the period was $42.9 million (49 cents).

Westinghouse Electric is a major manufacturer of the electrical and mechanical equipment required by power companies, railroads and industrial plants, as well as products for the government and consumer markets.

Chemical New York Corp., parent company of the nation's sixth-largest commercial bank, said yesterday its profits in the third quarter jumped 27 percent to $44.9 million from $35.6 million in the same period last year.

Per-share earnings were $2.88 compared with $2.26 in last year's third quarter.

Chairman Donald C. Platten said earnings were bolstered by higher interest income from loan operations of Chemical Bank, its principle subsidiary.

The bank's net interest income -- the difference between what it earned on interest from loans and what it paid in interest to depositors arose 22.5 percent for the July-september period to $256.4 million from $209.3 million in the same period a year ago.

The company lost $18.7 million in bond trading, due largely to a sudden and sharp run-up in interest rates. In last year's third quarter Chemical lost $8.8 million in bond trading.

Fees from trust and other services were up $4.5 million to $48.5 million. Loan loss provisions were $11.4 million, up from $11.1 million for the same period last year.

Chemical was the second major bank holding company to report its earnings for the third quarter.