An electrical machine caught fire early Monday morning at Sensata Technologies on Pleasant Street.

The sprinkler system in the building at 533 Pleasant St., contained the fire but smoke filled the third floor, where the machine is located, Deputy Fire Chief Tim Birch said Tuesday.

No injuries were reported.

Investigators estimated the fire, which was reported about 12:15 a.m. Monday, caused between $75,000 and $100,000 damage.

The machine was not operating at the time but was plugged into an electrical socket, Birch said.

Firefighters spent about three hours at the scene investigating and clearing smoke from the building.

The exact cause was undetermined but it appeared to be an accident, Birch said.