Vice President said yesterday that Sen. Edward M. Kennedy's planned Democratic platform and rules challenges could "create acrimony and division" at the party's August convention.

And he insisted, in an interview in his White House office, that "90 percent" of the Kennedy delegates "recognize it [the nomination fight] is over . . . want to reconcile this dispute and help President Carter win this election."

Mondale spoke out a day after Kennedy vowed in a New York speech that he would take his challenge to Carter and to the draft party platform onto the floor of Madison Square Garden at the Democratic convention.

Kennedy also indicated he will make an effort to revise the proposed convention rules and let the delegates "vote their consciences" instead of the previous candidate pledges.

Mondale dismissed the threat to Carter's nomination, saying that Carter will have "800 more delegates" than Kennedy and that they will stay with the president.

"They [the Kennedy forces] will try to make it appear it's a boss-run convention. They're going to allege there are hundreds of delegates out there who do not want to vote for the candidate to whom they're pledged. In fact," Mondale said, "that much-advertised theory has failed to be reflected anywhere.

"In the period since the last primary, there's been no erosion of Carter's strength. In fact, there's been a slight erosion of Kennedy's. And I know there are some who are for Kennedy out of loyalty who want to go to Carter as soon as they can."

Mondale said that since the June 3 primaries, he has had "a number of conversations with people who have supported and are supporting our opponent [Kennedy]." Without identifying individuals, he indicated that the talks have included many, if not all, of Kennedy's prominent labor union and congressional backers.

"Based on the conversations I've had," the vice president said, "with one or two exceptions, the Kennedy people know it's over. They want to be loyal to Ted, but they want to resolve it."

"Many of the Kennedy delegates who are voting with the senator on the platform issues are privately telling us they will be with us after the convention, and they want to resolve our differences and get on with the main campaign."

Mondale conceded that most of the Kenedy delegates would support the senator's decision to carry the platform fights on energy, economic and defense issues to the convention floor. But he insisted that most Kennedy backers "will want to see the debate conducted in a way that will permit us to win," and not use the three days in New York to create the spectacle of a divided, split and embittered party.

"We've had a lot of experience with conventions like that," Mondale remarked, "and it's always hurt. It's very clear the Republicans have their act together. They're going to have three days of a very positive, if somewhat boring, spectacle, and to the extent that we give the opposite impression, it's going to hurt."

While Kennedy labeled the draft platform "Democratic in name only," Mondale said its education, urban and economic planks offer "plenty of room for resolution of our differences, if that's what's wanted."

"But," he said, "I don't know what his [Kennedy's] plans are. We're the Democratic Party, and we should debate issues, but whether it's done in a respectful, responsible way or is just designed to create acrimony and division make all the difference in the world."

Mondale's comments -- while not as biting as those of others in the Carter campaign -- reflected a frustration with the continuing inability to put the Kennedy challenge to rest. Some suggest that Kennedy is paying more heed to the advice of a small circle of staff members than to the comments from his major backers in the party and its allied movements.