Suggesting that this may be just the first act in a larger play, Larry Carlson, president of Fitzpatrick Electric Supply Co., Muskegon, Mich., said Fitzpatrick has acquired Langstadt Electric Supply Co., Appleton, Wis. Carlson would not comment on why Fitzpatrick Electric Supply bought Langstadt Electric Supply. "There are a lot of things that we're not ready to div ulge and there are some other things happening at the same time," he said. Fitzpatrick Electric Supply, with $69.7 million in annual sales, is the nation's 64th largest electrical distributor, based on 1996 sales. Langstadt Electric Supply, with $24.6 million in 1996 sales, was 222nd.