It can move in ultra low pressure, Even the work voltage is 150v, it is output power may reach over 50% of original design, It can work normally in 180v. Safe friction clutch was designed in door opener. When load surpass the specialized or meet barrier, motor is free running. Thermal protection at 130 centigrade was built into motor winding after moving continually for about 30 minuets. Motor is cut off power automatically and ensure not burning winding.Emergency Key for power failure is easy to use. only rotate the key which insert the keyhole to 100 centigrade.