American Superconductor says it will close its Middleton plant by the end of the year and transfer the work to its headquarters in Massachusetts.
The plant makes voltage regulation and control devices for use in the electric transmission grid. The company declined to say how many employees will be affected by the closure. But, Madison Gas and Electric's directory lists 100 employees at the Middleton plant.
The State Journal reported the company's operations in New Berlin will not be affected.