Generator Failure
Seite/Page 112 Panda 8000-42NE PVMV-N.R01 - Kapitel/Chapter 8: Generator Failure
10.5.11
If you find any anormality, when doing this test, please ask your Fischer Panda dealer.
If the measured resistance values deviate from each other significantly, then there is probably a short within the
coils. A short within the coils can prevent the generator from achieving the required excitation and therefore from
reaching the rated power output. The values listed in the above table, represent the approximate range of accepta-
ble resistances. Most important is that the measures values do not deviate significantly from one another. Large resi-
stance value deviations between phases indicate a short-circuit in the windings. In this case the generator must be
newly wound by a qualified technician.
8.8
Measuring the Coil Inductive Resistance
Unfortunately a reliable assessment of the winding's performance cannot be attained through checking only coil resi-
stances. However, the symmetry of the coil resistances is a good indicator of winding performance. If the coil resi-
stances are symmetric, the next step is to measure the winding's inductive resistance using a special meter (capable
of measuring milli-Henrys).
The coil induction is measured and compared in the same manner as the electrical resistance (i.e. the windings are
compared for symmetry). These parts must have the same values.
Note: These values strongly depend on the method of measurement (e.g. used instruments)
An alternative test method to check the stator windings can be performed as follows:
1. Ensure that the connection to the circuit system is disconnected.
2. All electrical wires in the generator terminalbox must be disconnected.
3. Reconnect the battery connections.
4. Start the generator.
5. Measure the voltages between the following terminals and compare for symmetry: L1-N, L1-Z.
8.9
Generator provides no Voltage
8.9.1 Rotor Magnetism Loss and "Re-magnetizing"
After having stood idle for a longer period of time, or after having been shut down abruptly from operating under a
heavy electrical load, most asynchronous generators have difficulties achieving full excitation independently. The
remaining rotor magnetism is lost.
Notice!:
Before working on the System read the section "Safety Instructions" in this
Manual.
The magnetism required for excitation can be easily restored using a simple DC Battery. The generator must be
stopped to do this, that means the starter may not be actuated. DC is fed to a desired part of the winding from the
exterior for a short period. This can, for example, be carried out for by feeding DC to the windings from both termi-
nals of a 230V (115V) socket of the vehicles system. (This, of course, can only happen if there is no connection to
any power source). There must be a connection between socket and the generator (see diagram below). It suffices
if DC is applied for a short period (1-2 seconds). The remaining magnetism can be restored and the generator can
be started in the normal manner again.
