ABB ACS 502 Series, Installation & Start-Up Manual, Page: 78 / 92

Chapter 6 – Fault Tracing
6-4 ACS 502 Installation & Start-up Manual
Other Fault Situations
There may be other fault situations that need to be corrected. For example, if
nothing happens when power is applied to the ACS 502/504, refer to the
following flowchart for assistance.
If parameter 20.4.10 (Voltage Limit) is set to YES , the internal logic of ACS
502/504 prevents starting the drive if the DC bus voltage is over 117% of its
nominal value as derived from the Start-Up Data Parameter D (Supply
Voltage). The limit for preventing is 1.17 x 1.35 x V
IN
. If in doubt, check these
parameters and the DC bus voltage.
23 UNDER V 2 DC bus voltage does not rise over 80% of its
nominal value (1.35 x V
IN
) in 5 sec. after
connecting the input line. This fault message is
also displayed if the Start command is active and
voltage drops below 60% and does not increase
above 80% within 40 sec.
Check input line fuses and supply. If they are
OK, an internal failure has occurred. Contact
ABB Technical Support.
24 GND FAULT Current at start is more than 5% of the nominal
current I
N
. There may be a ground fault or a
voltage source in the motor circuit. This message
may also appear if the motor is switched from
bypass to ACS 502/504 too quickly, so that the
motor flux generates the current.
Disconnect the input line, wait 5 minutes and
check that the DC-voltage is zero, then
disconnect the motor cables and check the motor
circuit isolations. If there is no ground fault,
check the ACS 502/504.
The running ground fault detection circuit is
factory set to 2.5 amps by jumper S1 on the
ground fault sensing card (SNAT 7670 EFS). The
settings on the card are as follows:
A - 2.5 A
B - 5.0 A
C - 7.5 A
D - 10.0 A
Ground fault circuit measured current greater
than 2.5A. There may be a ground fault or a
voltage source in the motor circuit.
Fault message Possible reason Remedy