... brushless bathroom exhaust fan 1.High efficency, energy saving 2.Low noise 3.long life time 4.soft start 48V DC brushless bathroom exhaust ... protection6. the locked motor protection7. relay alarm output: when fan bus overvoltage, under-voltage, driver circuit over temperature ,motor ... connect to open regular contact;8. Reverse function: the fan can be reversed ,by use of computer or other controller ...