Montgomery County Council President Neal Potter yesterday unveiled his seven-member slate of running mates, including three other council incumbents, a real estate industry lobbyist, a sewer commissioner and the former president of a powerful county teachers union.

The Potter slate, called "United Democrats," will face a slate headed by council member Esther Gelman in September's Democratic Party primary.

The "United Democrats" slate, which is expected to be endorsed by County Executive Charles W. Gilchrist, includes the executive's strongest council backers--Potter, Scott Fosler and Ruth Spector, as well as the more combative Rose Crenca. Crenca tried to assert her independence even as the slate was being announced. "I don't believe in slates," she declared. "Unfortunately, the realities dictate you have to find some feasible way to run without ruining your budget."

The newcomers to the slate are Joan Hatfield, a lobbyist for the County Board of Realtors, Leonard Teitelbaum, a member of the Washington Suburban Sanitary Commission, and Henry Heller, a special education teacher and former head of the activist Montgomery County Education Association.

One theme that will divide the two Democratic council slates is how the council should relate to the executive branch. Gelman and her partners, David Scull and Michael Gudis, have accused the Potter faction of being a "rubber stamp" for Gilchrist.

Another council candidacy was announced by former Rockville Mayor William Hanna. He is expected to join the Gelman slate.