Some moms just have the knack for motherhood. They can raise, say, three strong-willed daughters, tempering the various rivalries and resentments, supporting them through triumph and tragedy, moving dead bodies in the middle of the night — when necessary — to avoid scandal, and all the while keeping the lord of the manor happy, matching wits with a haughty mother-in-law and juggling the needs of all those lady’s maids, cooks, under-butlers and footmen.

Such is the kind of maternal perfection that Elizabeth McGovern embodied playing the beloved Cora Crawley — Lady Grantham to us commoners — on the popular PBS series “Downton Abbey.”

Mrs. Conway, another matriarch of a tumultuous British family, and the new role that brings McGovern back to Broadway in the revival of J.B. Priestley’s “Time and the Conways,” is not that kind of mother. Not at all. And that suits McGovern just fine.

“Being the perfect mother is not that interesting, not very dramatic,” she recently admitted during a break from rehearsals. “I wanted to explore the flip side of motherhood — the imperfect mother. I mean, really, that’s Mrs. Conway.”

McGovern starts to chuckle.

“She gets it wrong … every single step.”

REVIVING A FORGOTTEN PLAY

When “Time” opened at the American Airlines Theatre this month, in this Roundabout Theatre Company production directed by recent Tony Award winner (and Port Jefferson native) Rebecca Taichman, it was the first time the play has been seen on Broadway since 1938 — and 25 years since McGovern’s last Broadway appearance as Ophelia in the Roundabout’s “Hamlet.”

The story about a bourgeois Edwardian family too comfortable and insular for its own good — and facing a new world at the end of World War I — sounds decidedly “Downton”-esque. But there is a bite, and a surprising modern-day relevance to this tale, that “Downton,” for all its intoxicating melodrama, lacks.

The first hint comes with McGovern’s entrance, in the midst of a house party. It’s soon clear that Mrs. Conway is one of those mothers not terribly fond of motherhood. She loves her children, but the frustrated singer in her clearly rues the day she gave up her show-biz dream. She is looser than Cora and, dare we say, drunker, flouncing down on sofas and talking candidly of her children even when they’re in the room.

“I find it thrilling to see her grab that stage, to see what a stage animal she is,” Taichman says.

Mrs. Conway’s British accent is somehow brassier, less lofty than milady Cora’s, and different from McGovern’s own American-British mashup. The Illinois native, who was something of a Hollywood “It” girl early in her career (“Ordinary People,” “Once Upon a Time in America,” “Ragtime,” which earned her an Oscar nomination) ditched Hollywood for London in the early 1990s, when she married British film director Simon Curtis. They have two daughters.

“We were talking the other day about her coming to New York for this play, and she said, ‘I feel so young doing this,’ “ recalls Anna Baryshnikov, who plays one of Mrs. Conway’s children, Carol. “I think she has a youthful spirit, and it works so well for her character.”

As does the empathy McGovern somehow inspires onstage.

“You care about Elizabeth as a person,” Taichman says. “There’s something about her and the energy she creates that draws you in.”

THE RIGHT TIME FOR “TIME”

For a little-known play, “Time” manages to have startling relevance. The political overtones become clear when Mrs. Conway swats away poor besotted Ernest, a working class bloke who takes a fancy to one of the Conway girls.

“He’s a working-class man who feels rendered utterly invisible and irrelevant to the bourgeois class,” Taichman says. His rage, once unleashed, will have devastating consequences.

And then there’s the parenting. While not a helicopter parent by any means, Conway’s grand visions of her children feels depressingly familiar.

“Our kids are all like gods and goddesses for us — they can’t be average,” McGovern says. “We’re always filling them with all this positive reinforcement, which wreaks havoc on them psychologically when they get out in the real world and learn they’re not geniuses.”

The real world, as the Conway kids soon discover, can be a tough and unforgiving place.

“I think Priestley was trying to remind us that life is full of both grief and joy, and they’re constant companions as we move through our lives,” Taichman says.

Both Cora Crawley and Mrs. Conway would surely agree.