22 Tests on Electrical Components22.1 Locked-rotor test for low voltage dc fans/motors in secondary circuits22.1.1 The purpose of this test is to determine if a low voltage dc fan or motor does not present a hazard in a locked rotor condition. Fans complying with the Standard for Electric Fans, UL 507 are considered to comply with this requirement without test.22.1.2 A sample of the fan or motor is placed on a wooden board, which is covered with a single layer of tissue paper, and the sample in turn is covered with a single layer of bleached cotton cheesecloth of approximately 40 g/m2.22.1.3 The sample is then operated at the voltage used in its application and with its rotor locked for 7 h or until steady conditions are established per 6.3, whichever is the longer.22.1.4 There shall be no ignition of the tissue paper or cheesecloth.