Checking The Ac Varistors - Ingeteam INGECON SUN 3Play Handbuch

Preventive maintenance

15.6. Checking the AC varistors

It is advisable to periodically check the AC varistors to ensure that the overvoltage protection is not damaged.
To do so the unit must be completely disconnected from voltage:
1. On units without a DC circuit breaker, the voltage must be cut off from both PV arrays at the switch
located upstream of the unit.
2. Use the DC circuit breaker on units fitted with the same.
3. Cut the AC voltage using the AC circuit breaker or with the switch located upstream of the inverter.
4. Wait at least five minutes until capacitances are fully discharged.
5. Use a multimeter with category III-1000 Volts insulation to measure the voltage in both PV arrays and
ensure that both readings are zero.
6. Measure the voltages at the input terminals (between phases and neutral) to ensure that they are zero.
7. Release the varistors by using a screwdriver to make contact between their terminals.
8. Use a multimeter set to measure resistance to measure the resistance between the varistor "fuse" pins
(pins 2 and 3).
1
9. The resistance should be in the order of 0 Ohms. If not, the thermal varistor fuse is open and therefore
the varistor is not working.
ABI2011IQM01_A - Installation and usage manual
AC Varistors
3
2 1
VA FU
3 2
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