The Senate Banking Committee yesterday voted 17-3 to approve President Reagan's nomination of David S. Ruder to be chairman of the Securities and Exchange Commission and unanimously approved Reagan's choice of Alan Greenspan to be Federal Reserve Board chairman.

There was no immediate indication when the full Senate will act on the nominees.

Committee Chairman William Proxmire (D-Wis.) and Sens. Jim Sasser (D-Tenn.) and Terry Sanford (D-N.C.) opposed Ruder. The Northwestern University business law professor is nominated to replace John Shad at the SEC. Shad is now ambassador to the Netherlands.

Greenspan, a New York economist, was approved by the committee to replace Paul A. Volcker. Volcker will head a new nonprofit commission on public service.

In explaining his reservations about Ruder, Proxmire said insider trading and securities fraud plague the nation's securities markets more severely than any time in the past 50 years.

"A scholarly professor of securities law with little or no experience in the capital markets in any capacity would have trouble restoring public confidence in the market under any circumstances," said Proxmire. "But when that professor brings to the chairmanship in this year 1987 no record of any concern about securities fraud or the abuses involved in insider trading, it is impossible for this senator to vote to confirm his nomination.

"What the SEC needs as chairman is a tough, no nonsense enforcer," he said. "A law professor who had demonstrated support for vigorous enforcement would deserve consideration. But a professor who has written about the securities laws for years without expressing support for vigorous enforcement will not have this senator's confirming vote."