RALEIGH, N.C., NOV. 6 -- Sen. Jesse Helms (R-N.C.) was reelected to a fourth term tonight over Democratic challenger Harvey Gantt, following conflicts over broken voting machines and court orders extending voting hours.

With 93 percent of the precincts reporting, Helms led 54 percent to 46 percent, a lead he had maintained most of the evening.

Claiming victory in a ballroom full of cheering supporters here, Helms said that when he was first elected to the Senate 18 years ago, he "pledged to say no to the tax-and-spend liberals in Congress, even when it meant standing alone and saying no alone." His victory, he said, was "a mandate to continue to say no."

Earlier, Helms joked to a reporter that he "just lucked out."

Conceding, Gantt told his backers he had "wanted to appeal to your very best hopes and aspirations" in promoting issues like health care and children's needs. He noted that late votes had yet to be counted, but said, "to be fair about it, it doesn't look that good."

Long lines of voters waited to cast ballots in late afternoon in Durham County, where officials said voting machines stopped working. Judges ordered the polls to remain open until 10 p.m. there and until 8:30 p.m. in the county around Greensboro.

Helms's backers unsuccessfully sought a higher court order to halt the voting extension in Durham County, where they said voter fraud had occurred in the past.

But Gantt supporters said the technical problems may have hurt their candidate. "When the machines failed, a lot of people went home. People are out there trying to get them back to the polls," Susan Jetton, Gantt's press secretary, said early in the evening. Before the polls closed, Gantt and his campaign manager, Mel Watt, went from Raleigh to Durham along with a busload of about two dozen Gantt workers in order to encourage voting in Durham.

Gantt, an architect and former mayor of Charlotte, had drawn even with Helms in final pre-election surveys as he tried to become the first black senator from the South since Reconstruction.

The Helms campaign appeared to have energized his supporters with a late advertising blitz that focused on Gantt's backing for gay rights and civil rights legislation vetoed by President Bush, and on his participation in a profitable television station deal. Turnout on a clear, beautiful day was very high, possibly more than the state's record 55 percent for an off-year election, officials estimated.

"We knew {the win} was coming and it's great," said Bob Caudle, an aide in Helms's Raleigh office.

Bob Shipley, a Raleigh investment expert, said of Helms: "What he was representing was what the citizens of the state were looking for. You're talking about a sense of values."

Exit polls, which at one point showed Gantt with a narrow lead, greatly understated Helms's backing and overstated Gantt's. Democratic officials said Helms needed about 30 percent of their party's vote to win.

Helms, 69, was favored by 60 percent of white voters, while Gantt, 47, received 94 percent of the black vote, according to the exit polls. Generally, the surveys indicated that older voters were more likely to pick Helms.

The voting problems chiefly affected precincts with large numbers of black voters, according to Robert F. Bauer, general counsel for the Democratic Senatorial Campaign Committee. In areas around Greensboro, for instance, voters found only one sign-in book at their polling places. The usual practice is to use several books, each containing segments of the alphabet, Bauer said.

The close campaign, the most watched Senate race in the country, pitted a conservative Republican who preaches a limited role for government against a liberal Democrat who wants more federal aid for his home state.

The strength of Gantt's appeal created some uneasiness among Republican Party officials. "It's sounding good, but we're all jittery right now," said Tom Ballus, spokesman for the state Republican Party, during the count. "It's always a close race with Jesse Helms."

In 1984, Helms defeated former governor James B. Hunt Jr., 52 percent to 48 percent, after trailing by 20 points early in the campaign.

Before the polls closed, Democratic leaders said they had run a strong campaign. "We've done everything we know to do," said E. Lawrence Davis, state Democratic chairman.

The final independent polls published last week generally showed the race to be a dead heat. However, pre-election surveys of contests between a white and a black candidate frequently have understated the Election Day strength of the white candidate.

In Raleigh, where Gantt was expected to have an edge, Helms supporters praised the incumbent's ideological consistency on issues like abortion.

"I've always voted for him," said Wayne Adams, a white self-employed investigator. "I think he's a constant. He'll take a moral or political stance and then stand by it."

In heavily black precincts, Gantt appeared to get a large turnout, unlike former Atlanta mayor Andrew Young, whose Senate bid faltered in Georgia's Democratic runoff this year. Almost 700 of 1,500 voters had cast ballots in the black middle-class neighborhood of Biltmore Hills before noon. "The whites will have to deliver. We know the blacks will deliver," said Onelia W. Foxwell, Democratic chairman for Precinct 35.

Gantt, who entered the race in June as a decided underdog, appeared to pull even with Helms in September.

The Gantt campaign portrayed Helms as an obstructionist who has blocked federal aid that could bring social and economic progress to North Carolina, where rural poverty endures despite high-tech growth in the cities and where Scholastic Aptitude Test scores lag behind the national average despite various school improvement efforts.

Helms, using campaign tactics that have worked for him in the past, launched a value-laden attack on Gantt for his support of abortion rights, opposition to the death penalty and espousal of "extreme liberal values."

In the last days of the campaign, Gantt tried to fight back by accusing Helms of waging "an outrageous smear campaign" and telling "lies" about the TV station deal and his position on gay teachers.