Siemens Eupec, Manual

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MicroHarmony Cell Sizes 40 - 260A Manual Repair Hints
19001467: Version 1.0 8-3
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8
8.5.3 Electrolytic Capacitors
For capacitors that do not exhibit any signs of vent out gassing, bulging, leakage, sleeve damage, terminal damage,
and have less than 1 year of service (operating or non-operating), they may be re-used and supplemented with the
approved capacitor of the same manufacturer's part number or Siemens MDIT number, if:
1. The re-used capacitors are evenly re-distributed between parallel capacitor groups so that each group has the
same number of re-used capacitors and have no more than 2 years of operation life on them.
2. Capacitor does not exhibit leakage current of more than 1mA per can at rated voltage.
The following procedure may help in checking the general health of a capacitor bank following a cell failure due to
over voltage:
1. Disconnect the bleeder resistor and measure each section with an ohmmeter. Verify that resistance is within
spec.
2. Reconnect the resistor and slowly apply AC voltage to the cell, while measuring the voltage across each
series capacitor group, up to rated AC input voltage. If all capacitors are exhibiting less than normal leakage
current, then the voltage measured for any group should equal the ratio of the resistance connected, divided
by the total resistance measured, times the total sum of the voltage.
Vc1 = R1 x (Vc1 + Vc2 + Vc3) / (R1 + R2 + R3)
For any measured voltage that is not within
±
10% of this calculation, it may be assumed that one or more
capacitors in that group is exhibiting abnormal leakage. These faulty capacitors must not be re-used.
8.5.4 In all cases the cell must pass all specified testing before re-using
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