The D.C. City Council voted last night to extend the moratorium on conversions of apartments into condominiums and cooperatives until early in November.

The council also approved a real estate tax rate for homeowners of $1.22 for each $100 of assessed valuation, a cut of 22 cents below the rate proposed by Mayor Marion Barry and 31 cents below last year's rate.

Despite the cut, the typical homeowner will pay about the same in real estate taxes because of higher assessments.

The $1.22 rate will be the basis for tax bills that will be mailed about Aug. 15, with the first installment due a month later.

Although the condominium moratorium issue has pitted tenant groups against the city's real estate industry, there were few representatives of either side in the audience for last night's subdued debate on extending the moratorium, due to expire Aug. 27.

As it did when it first enacted the moratorium on May 22, the council invoked emergency powers last night to extend the restrictions. Emergency laws are effective for up to 90 days.

The first moratorium responded to a growing volume of protests from apartment dwellers who contended that a tide of condominium conversions was squeezing them out of their homes.

The central question last night was not whether the moratorium would be extended, but for how long.

Willie J. Hardy (D-Ward 7), chairman of the council's housing committee, proposed a 60-day extension. Wilhelmina J. Rolark (D-Ward 8) immediately offered an amendment stretching it to 90 days. Rolark won on a roll-call vote, 9 to 4.

"There is nothing magic about 90 days," Hardy insisted, saying the council should move swiftly to pass permanent legislation regulating condominium conversions and invoke future extension of the moratorium as needed. David A. Clarke (D-Ward 1) said there is no way the council could write a permanent bill in Hardy's shorter time period.

The new moratorium will tak effect immediately upon its expected signing by the mayor. Barry has 10 days to sign it.

That means the new moratorium would go into effect about 15 days before the present one expires. In practice, that will squeeze the new moratorium down to about 75 days, making it expire around Nov. 10.

Voting for the 90-day extension were Rolark, Clarke, Council Chairman Arrington Dixon, Charlene Drew Jarvis (D-Ward 4), Hilda Mason (Statehood (At-Large), John L. Ray (D-At Large), Polly Shackleton (D-Ward 3), John A. Wilson (D-Ward 2), and Nadine Winter (D-Ward 6).

Voting against it were Hardy, Betty Ann Kane (D-At-Large), Jerry A. Moore Jr. (R-At-Large) and William R. Spaulding (D-Ward 5).

The new real estate tax rates were proposed by Wilson, chairman of the council finance committee. Despite their differences from the mayor's rates, they are exptected to yield slightly more revenue.

The rates were approved on a voice vote without debate.

On an average city home or condominium unit assessed at $60,000, the rate Barry proposed would produce a $734 tax bill, after deducting the $9,000 homeowners exemption from the assessed value.

Last night's decision will cut such a bill to $622, a difference of $112.

The owner of the same house last year would have paid, at the old rate, just about the same amount he will pay this year, since average assessments have risen 18 percent.

For commercial properties, including retail stores, offices and large apartment buildings, the rate set by the council last night is $1.83 for each $100 valuation. The mayor proposed $1.72.

For a third category - rental properties of up to five units owned by landlords who do not live in the building - the rate will be $1.54, compared to the mayor's proposal of $1.48.

The mayor has little choice but to accept the rates set by the council. After last night's meeting, the council adjourned for the month of August and any veto by the mayor would require that the council be called back into special session with a probable delay in mailing tax bills.

In other action, the council enacted a bill requiring all family health insurance policies sold in the city to include mandatory coverage of babies from the moment of birth. In some cases, such coverage is now optional. The measure is expected to increase annual insurance premiums from $2 to $5.

The council also enacted legislation removing the statutory $100,000 limit on annual appropriations to the Office of the People's Counsel, the city agency that represents consumers in utility rate cases.