Veichi AC310, Service Manual

Page: 60 / 63

59
AC310 Universal AC Drive Service Manual
switching power supply, which will lead to no display, so, when there is no display, test
whether the 0Ω resistor is normal
.
4.2 Power-up or Operating Undervoltage (L.U.1, E.LU2),
Overvoltage (E.OU1/2/3/4) Fault
The power supply is added to the normal voltage value (380VAC/510VDC), and the
undervoltage fault is still displayed. Possible causes and countermeasures:
1. Voltage calculation error on the control board
Cause: The voltage on the control board is calculated incorrectly, causing the CPU to
misreport undervoltage and overvoltage.
Measurement method: according to the maintenance of the control board VPN circuit
maintenance
2. Power board VPN acquisition circuit errors
Cause: Errors in the VPN acquisition circuit on the power supply board cause the
voltage on the control board to be calculated incorrectly, and the CPU mistakenly
reports undervoltage or overvoltage.
Measurement method: According to the method of repairing the VPN circuit on the
power supply board.
3. When the 24V switching power supply fails, the relay cannot be absorbed, so there
will be voltage loss on the charging resistor, resulting in undervoltage.
4. If the voltage level is set incorrectly, undervoltage will be reported. When the voltage
level of S2 is set to the voltage level of T3, an undervoltage fault will be reported.
5. If the input voltage at the site is too high or too low, an overvoltage or undervoltage
fault will be reported.
6. Add a suitable braking resistor to release the excess energy from the bus voltage so
that overvoltage is not reported.
7. Energy braking point is set too high, resulting in overvoltage. (Note that overvoltage
suppression is turned off when energy braking is used)
8. The overvoltage suppression point is not turned on, resulting in overvoltage.
4.3 OC Fault (OC1, OC2, OC3, OC4)
1. IGBT module short circuit.
Cause: IGBT module AC drive short-circuit, short-circuit upper and lower bridge,
short-circuit with ground, resulting in excessive current and thus report OC.