Rockwell Automation 1391ES AC Servo Controller - Manual (Page 65)

Troubleshooting
Chapter 10
10-63
Table 10.A
LED Descriptions and Fault Diagnosis
LED
OVERTEMPERATURE
(RED)
Potential Cause
OVERTEMPERATURE LED is Illuminated
The logic supply (
±
12V DC, +5V DC) circuits have malfunctioned
(fuse blown etc.) or the AC input at TB4-19, 20, 21 is incorrectly wired.
The heat sink thermal overload has tripped. One or more of the
following may have occurred:
1. The cabinet ambient temperature is above rating.
2. The machine duty cycle requires an RMS current exceeding the
continuous rating of the controller.
3. The integral fan is not functioning.
4. The airflow access to the controller is limited or blocked.
LED Description
The controller contains a thermal
switch on the heat sink which
senses the power transistor
temperature. If the temperature is
exceeded the LED will illuminate.
CONTROL (POWER) FAULT LED is illuminated
1. Open or short circuit on resolver wiring.
2. The input line voltage is out of tolerance.
2. The transformer auxiliary logic supply winding is open.
3. The logic supply (
±
12V DC, +5V DC) circuits have malfunctioned
(fuse blown etc.) or the AC input at TB4-19, 20, 21 is incorrectly
wired.
A fault will occur and the LED will
illuminate, if:
1. The logic supply rises or drops
10% from its nominal value
or
2. The resolver wiring is open or
shorted.
POWER FAULT
(RED) POWER FAULT LED is Illuminated
1. The current through any one of the power transistors has exceeded
300% of the controller’s current rating.
2. Malfunctioning power transistor.
3. Shorted Lead.
4. Winding to case motor capacitance is out of tolerance.
The current through the power
output transistors is monitored. If
the current exceeds a fixed level
(greater than 300% of controller
rating) the LED will illuminate.
CONTROL (POW-
ER) FAULT
(RED)
OVERVOLTAGE
(RED) OVERVOLTAGE LED is illuminated
The logic supply (
±
12V DC, +5V DC) circuits have malfunctioned
(fuse blown etc.) or the AC input at TB4-19, 20, 21 is incorrectly wired.
The power bus voltage has exceeded 405V DC.
1. Logic Board is malfunctioning and incorrectly sensing the bus
voltage.
2. A vertical axis with insufficient counterbalancing is overdriving the
servomotor and causing excessive energy to be returned to the power
supply bus.
3. The system inertia is too high causing excessive energy to be
returned to the power supply bus.
4. Input line voltage exceeds the maximum controller input voltage
rating.
5. The position controller acceleration / deceleration rate is incorrectly
set.
6. The shunt regulator or transistor has malfunctioned.
7. Shunt regulator fuse has blown.
8. Shunt regulator resistor not connected to controller.
The DC Power Bus is continuously
monitored. If it exceeds a preset
level a fault is sensed, the power
supply is disabled and the LED is
illuminated.
UNDERVOLTAGE
(YELLOW) UNDERVOLTAGE LED is illuminated
The power bus voltage has dropped below a preset DC value
1. The power contactor (M) has not energized or has dropped out.
2. The input line voltage is low.
3. The shunt regulator circuit has malfunctioned and is placing the
shunt resistor across the power bus.
4. The power bus capacitor has malfunctioned.
5. The circuit breaker (MCB) has tripped.
6. The three-phase input line is open.
7. Transformer is supplying the wrong line voltage or has
malfunctioned.
If the DC Power Bus drops below a
preset level, a fault occurs and the
LED is illuminated.