GE Industrial Solutions MX350 Instruction manual - Manual (Page 30)

2–14 MX350 AUTOMATIC TRANSFER CONTROL SYSTEM – INSTRUCTION MANUAL
ELECTRICAL INSTALLATION CHAPTER 2: INSTALLATION
Dielectric strength testing
Figure 16: Testing for dielectric strength
It may be required to test for dielectric strength (“flash” or “HI-POT”) with the MX350
installed. The MX350 is rated for 1.9 kV AC for 1 second, or 1.6 kV AC for 1 minute (per UL
508) isolation between relay contacts, CT inputs, VT inputs and the surge ground terminal
SG. Some precautions are required to prevent damage to the MX350during these tests.
Filter networks and transient protection clamps are used between VT input and the surge
ground terminal. This is intended to filter out high voltage transients, radio frequency
interference (RFI), and electromagnetic interference (EMI). The filter capacitors and
transient suppressors may be damaged by continuous high voltage. Disconnect the surge
ground terminals (C8 and D8) during testing of VT inputs. The CT inputs, control power, and
output relays do not require any special precautions. Low voltage inputs (less than
30 volts), and RS485 communication ports are not to be tested for dielectric strength under
any circumstance (see above).
Do not HI-POT test
HI-POT test at 1.9 kV AC for 1 second, or
1.6 kV AC for 1 minute (per UL 508)
LINE FAULT
ON
POWER FAULT RESET
kV
VOLTAGE ADJUST HV ON
DIELECTRIC STRENGTH TESTER
BLACK RED
Remove surge ground during test
*
CPU module
C8 C7 C6 C5 C4 C3 C2 C1
S
u
rg
e
G
round
D1
D2
D3
D4
D5
D6
D7
D8
CT
Mod
u
le
CT1
CT2
CT3
CT4
Power
supply
L N G
Automatic Transfer Control System
VT1 module
VT
1
VT
3
RS485
Thermistor
VT
2
Cor
e
balance
S
u
rg
e
G
round
889738A1.CDR
+ – C + – R I SG
* * * * *
D8 D7 D6 D4 D3 D2 D1
S
u
rg
e
G
round
D5
VT
1
VT
3
VT
2
VT2 module
* * * * *