By a vote of 498-107, members of the Cambridge Teachers Association (CTA) yesterday approved a new contract that will give them salary increases of 19 percent over a three-year period.

The negotiating team was present at the voting site to answer questions, but no formal discussion took place. The contract needed only a simple majority of teachers' votes to be approved.

The teachers' old contract expired on August 31, and teachers had agreed to work at the previous rates while negotiations for the new contract continued. The wage increases agreed to in the new contract will be retroactive to September 1.

The union presented the contract to teachers and gave them the opportunity for discussion last Monday, after the negotiating team of CTA representatives, school committee members, and Mayor and School Committee Chairman Alfred E. Vellucci tentatively approved the contract.

Marie Orben, chairman of the CTA, said that most of the objections to the contract stemmed from the fact that raises were not the same across the board. Teachers with more than 12 years seniority will receive "professional improvement incentives" in the from of slightly higher raises each year, she said.

In addition, Orben said, teachers with bachelors' degrees are paid less than those with masters' degrees, even after many years' experience. To help those with bachelors' degrees, she said, she has begun negotiating with the school system's new superintendent, Mary Lou McGrath, to help teachers earn their masters' degrees quickly.

Despite disagreements, most of the teachers and school committee members involved appeared satisfied with the final product. Orben said she was not surprised at either the decision or the high margin of victory.

Lawrence Weinstein, school committee member, said he too was very happy with the decision.

"I think it's a very fair contract," he said. "Not that we'll ever be able to pay good teachers what they're worth, but I think we were able to reach a mutually satisfying agreement."