ASTAT XL Service Manual
Functional Tests
2
Functional Tests
Use the tests in this section to identify the cause of problems with the soft starter.
NOTE
Before changing any parameter settings, save the current parameter set to a file using GE
ASTAT Setup Tool ed.3 or the soft starter's Save User Set function (see the soft starter user
manual for more information).
2.1
Power Circuit Test
This procedure tests the soft starter's power circuit, including the SCRs, Backplane PCB, Model PCB and
Main Control PCB.
Use a 500 VDC insulation tester on the 200 ohm scale or a standard multimeter (voltmeter).
1.
Isolate the soft starter from the incoming mains supply and remove the control voltage.
2.
Disconnect the motor cables and any external bypass contactor cables from the soft starter.
3.
Allow the soft starter to cool to room ambient temperature.
4.
Using a meter, check the resistance across each phase of the soft starter in both directions.
•
1/L1 to 2/T1, 2/T1 to 1/L1, 3/L2 to 4/T2, 4/T2 to 3/L2, 5/L3 to 6/T3 and 6/T3 to 5/L3.
5.
If any reading is less than 200 ohms, the SCR or internal bypass relay has failed short circuit and
must be replaced.
NOTE
Events that damage SCRs can often damage the Backplane PCB as well, although the Main
Control PCB may be undamaged. Replace the damaged SCR(s) and Backplane PCB, then
check for correct operation, before replacing the Main Control PCB.
SCR damage is almost always caused by external influences.
If the MOVs and/or surrounding circuitry on the Backplane PCB show signs of physical
damage, the most likely cause is overvoltage.
If the MOVs and/or surrounding circuitry on the Backplane PCB do not show signs of
physical damage, the most likely cause is overcurrent.
See
SCRs
on page 13 for information on typical causes of SCR damage.
2.2
Start Performance Test
This procedure tests for correct operation of the ASTAT XL during start.
1.
Connect the ASTAT XL to mains voltage, control voltage and to a motor.
2.
Set
Motor FLC
(parameter 1A) to match that of the motor.
3.
Set
Start Mode
(parameter 2A) to 'Constant Current'.
4.
Set
Current Limit
(parameter 2B) to a level which will supply sufficient start current to enable the
connected motor to produce enough torque to easily accelerate to full speed.
Calculate expected start current by multiplying
Motor FLC
(parameter 1A) by
Current Limit
(parameter 2B). If the secondary parameter set is being tested, multiply
Motor FLC-2
(parameter 1C)
by
Current Limit-2
(parameter 3B) instead.
5.
Initiate a start and measure the actual start current. This can be done by viewing the Phase
Currents screen or with a clip-on ammeter.
If the measured current is equal to the actual start current on all three phases, the soft starter is
performing correctly.
NOTE
During Start mode, the Run LED on the keypad should flash.
4
DET-813
