15V supply interfered
Lenze · SHB4800/4900
What does U15 mean?
This fault indicates an issue with the drive's internal 15V power supply, which typically powers internal control circuitry, sensors, or external devices. By default, this critical condition triggers a full TRIP, inhibiting all ignition pulses and resetting the Ready signal, as instability in this supply can compromise the drive's internal operations and safety functions. Manual reset is required.
Complete Troubleshooting Guide
- 1
Disconnect external devices: If any external sensors or devices are powered by the drive's 15V supply, disconnect them one by one to isolate a potential short circuit or overload.
- 2
Check internal components (if safe): Visually inspect the drive's control board for any signs of damage, burnt components, or bulged capacitors.
- 3
Measure 15V supply (if test points available): With the drive powered, if safe test points are accessible, verify the actual 15V supply output.
- 4
Check for short circuits: Use a multimeter in resistance mode (with power off) to check for shorts on the 15V rail if accessible.
- 5
Consider control board replacement: If no external cause is found, the internal 15V supply circuit on the control board may be faulty.