Delta Air Lines will give its non-union employees their first raises in three years on Aug. 1 and eliminate its two-tiered wage system, the company said.

The company has paid workers hired since Nov. 15, 1983, less than those with more seniority. When the raises are effected, non-union workers will be paid at the higher level, Delta spokesman James H. Lundy said.Lundy would not confirm the size of the increases, but employees reported raises of 3 percent to 5 percent.

Delta employs 54,000 people nationwide. Of that number, 47,500 are non-union; pilots and flight dispatchers do have union representation.

Although their last raise was in October 1985, Delta employees are the industry's highest paid. Figures compiled by PaineWebber Inc. list the worth of the average Delta employee's wage and benefits package as $49,465 last year, compared with the industry average of $43,846.

Some workers said there was dissatisfaction among employees over the three-year wage freeze because the company has been earning record profits.

"There has been a lot of grumbling because we knew we were making a lot of money," said the worker who did not want to be identified. "It was tough for the older employees because we were used to getting raises every year. This was the longest we had ever gone without a raise."

A mechanic, who also did not want to be named, said skilled workers on the lower-paid "B" scale were growing impatient with the company.

"We have a lot of B-scale mechanics who are going over to UPS (United Parcel Service) to become airplane mechanics because they're getting tired of this," he said.

Airline analyst Julius Maldutis of Salomon Brothers Inc. said several airlines adopted two-tiered wage scales starting in 1983 to try to keep costs down without angering present employees.

But today, he said, "virtually everyone has abondoned the idea because it just causes friction--if not outright animosity--among the workers."