ABB PSTX370 Service Manual page 76

4.8.1 Test the SCR
IMPORTANT NOTE
Only perform the SCR-test if the
Softstarter displays one of the following
commandos: "Short circuit fault" or
"Open circuit thyristor fault".
Replace SCR if the result of the test
shows under 1 Mohm.
DISMANTLE THE SOFTSTARTER
Remove main power cables and control
cables
Disconnect the main power cables and the control
4
cables as described in chapter 4.3.3, step 1-3.
1. Remove front cover
1
Loosen (1x)
bracket.
2
Loosen (4x)
Remove the front cover by lifting it upwards from
unit. Ensure that screws do not come loose and fall
down on the PCBA upon removal.
3
Lift out the PCBA from unit (at this point still
mounted on bracket) to facilitate continued service.
2. Disconnect SCR cables from PCBA
Mark the SCR cables with 1, 2, 3 prior to
disconnecting them to ensure proper re-
connection. Note that markings are to be made
in accordance with existing data available on the
PCBA bracket.
1
Disconnect the three SCR cables from their
terminals on the PCBA using a long-nose plier.
2
Pull out the three SCR cables from the cable
inlets on the PCBA bracket.
3. Connect the Megger to the Softstarter
1
Connect the black megger contact to the main
terminal 1L1 on the Softstarter.
2
Connect the red megger contact to the main
terminal 2T1 on the Softstarter.
3
Set the megger on 500V. Press and hold the
Test button. Note the result.
Also use 500V for 690V softstarters.
Service PSTX470...570 | Service Manual |
76
Torx 15 M3,5x12 on the HMI
Torx 20 M4x12.
1SFC13105M0201
1
1
2
2
1
2
3
M
OFF
250V
500V
1000V 3
M
M
OFF
250V
500V
1000V
Tx 15 Tx 20
M3,5 x 12 M4 x 12
3
4.8.1_1
4.8.1_2
1
2
4.8.1_3