Code ov (Alarm): DC Bus Overvoltage

Code type: Alarm / minor fault Manual section: Yaskawa A1000 Troubleshooting Surge voltage present in the drive input power. - Install a DC reactor or an AC reactor. - Voltage surge can result from a thyristor convertor and a phase advancing capacitor operating on the same drive input power system. The motor is short-circuited. - Check the motor power cable, relay terminals and motor terminal box for short circuits. - Correct grounding shorts and turn the power back on. Ground current has over-charged the main circuit capacitors via the drive input power. Electrical signal interference causes the drive to operate incorrectly. - Review possible solutions for handling electrical signal interference. - Review section on handling electrical signal interference and check control circuit lines, main circuit lines and ground wiring. - If the magnetic contactor is identified as a source of noise, install a surge protector to the MC coil. Set number of fault restarts (L5-01) to a value other than 0. PG cable is disconnected. Reconnect the cable. PG cable wiring is wrong. Correct the wiring. Electrical signal interference along PG encoder wiring. Separate PG wiring from the source of the noise (often output wiring from the drive).