The Democratic National Committee yesterday gave final approval to new rules for the 1984 presidential nomination process that will put more than 500 elected and party officials into the convention hall as uncommitted delegates.

With a minimum of debate, the committee sanctioned a system where the House and Senate Democratic caucuses will name up to three-fifths of their members as unpledged delegates. In addition to the roughly 200 members of Congress, another 350 or so state and local elected officials and party leaders will be picked by their state parties for the uncommitted slots that will comprise about one-seventh of the total convention membership.

A move to make all 350 members of the DNC also automatic, unpledged delegates was ruled out of order yesterday by party chairman Charles T. Manatt, but may surface later, raising the possibility of an even larger uncommitted bloc.

Creation of the big bloc of uncommitted votes for party power-brokers marked a major reversal from the trend of the past dozen years, when the Democrats rewrote their rules to encourage the greatest participation by grass-roots people. In many cases, those who came to the caucuses or voted in the primaries turned out to be issue activists or candidate enthusiasts.

North Carolina Gov. James B. Hunt Jr., who headed the commission that drafted the rules, told the DNC members the new rules will make it more likely that the typical Democratic voter "can look at the convention and feel, 'I'm pretty well represented there.' "

Rep. Gillis W. Long of Louisiana, chairman of the House Democratic caucus, who had lobbied hard for the uncommitted delegate status for his colleagues, said the change will "help end the division" between officeholders and party activists and thereby "help us govern better" when Democrats recapture the White House.

While Hunt insisted the new rules still kept the party "truly open," he conceded in his speech that the motive for change was the belief that the candidates and issues pushed forward by the old system "had negative consequences" for Democrats' chances of winning the presidency and running the government.

The only major challenge to the Hunt commission recommendations centered on a rule restoring the states' option to elect individual delegates directly by plurality vote from congressional districts, and that challenge was buried by a 4-to-1 ratio.

The "loophole primary" had been used by Maryland and a dozen other organization states including Illinois, New York, Ohio, Pennsylvania and Texas until it was banned in 1978 as a violation of the principle of proportional representation.

This is because a candidate can win all the delegates from a congressional district with a plurality of the vote, rather than sharing them with the candidates who finish second and third.

That change--and another allowing states to award a bonus delegate to the top candidate in each district--may make it easier for a front-runner to roll up a large and exaggerated advantage by winning primaries in the big states, assuming most of those states restore the old direct-election primaries.

Other changes approved yesterday are likely to have smaller consequences for the 1984 presidential nomination battle.

The voting period will be shortened slightly from 1980, with the leadoff Iowa precinct caucuses moved back five weeks from the third week of January to the last week of February. New Hampshire's kickoff primary moves back from late February to the first week in March.

But as the early visits by Democratic hopefuls to those states indicate, the campaigning there is likely to be just as protracted and the media attention to their small-scale verdicts just as heavy as in the past.

Iowa and New Hampshire were given specific exemptions from the three-month "window" in which all other states must conduct their delegate selection. An effort to provide a similar exemption for the Maine caucuses was voted down yesterday, as was a last-ditch try to allow Wisconsin to hold its "open primary," in which Republicans and independents may help pick the Democratic nominee.

The Supreme Court last year upheld the DNC's right to restrict voting in all primaries to Democrats.

The new rules are also intended to bury the controversy that erupted at the 1980 convention over binding the delegates to their original candidate pledges.

The new rules end the threat of replacement of delegates who bolt their original choice and require delegates only to "reflect in good conscience the sentiments of those who elected them." However, they preserve the candidates' original right of approval of delegates running in their name.

The DNC also accepted the report of a commission that urged the party to make greater financial and political efforts to help low and moderate income people participate in the convention and other party affairs.

And, in a somewhat belated gesture, it passed a lengthy resolution commending President Carter and his wife for their contributions to the country and the party. One member objected to the surprise resolution, offered by the president of the Georgia AFL-CIO, but Manatt gaveled it through before any real controversy developed.