TROUBLE SHOOTING
EN / WHISPER 3,5 / May 2006
27
5.3.3
Winding resistant values
If after establishing and correcting any fault on the
capacitor and diodes output is still low when separately
excited, then the main rotor, stator and exciter stator
winding resistance should be checked as the fault must be
in one of these windings. The respective leads must be
disconnected before taking the readings.
Resistance values should be within 10% of the values
given in the table below:
Resistance
50Hz
•
Resistance both main stator windings
in series
1.2 Ohm
•
Resistance both rotor windings
2.1 Ohm
•
Resistance battery charger winding
0.15 Ohm
•
Resistance exciter stator winding
2.4 Ohm
5.3.4 Meggering
One can try to measure resistance between the housing
and the windings with a multimeter which should read
infinity. When readings are infinity but a fault is suspected
one can do a high voltage resistance test (MEGGERING)
This procedure should be carried out by an expert
5.4
SPECIAL PROCEDURES ENGINE
5.4.1
Setting the RPM
RPM is set by the manufacturer and should not need
readjustment! However a very slight offset after running in
could occur. RPM can be measured by a frequency meter.
Before readjustment check any other explanation for the
wrong speed. Engine speed is set at the factory at nominal
3000 (50 Hz) RPM. A RPM drop of 5% at full load is
acceptable. Therefore a no load setting should be at ±
3150 RPM = 52.5 Hz. Under no circumstances should the
RPM be under full load below 2940 RPM = 49 Hz. When
no cause can be found for a wrong speed, the setting can
be adjusted: It is very important to identify the correct
setting assembly (refer to fig. 16).The screw is to be
locked in position with the lock-nut.
5.4.2 Tightening
torques
Valve clearance, refer to Maintenance, §4.2.3.
Cylinder head screws M10x1,5:
51,9 to 56,8 Nm; 5,3 to 5,8 kgf-m.
Rocker arm bracket mounting: M8 x 1,25:
23,5 to 27,4 Nm; 2,4 to 2,8 kgf-m.
5.4.3
Measuring exhaust backpressure
The exhaust system must be of adequate size -1 5/8”/ 40
mm no more-no less -and maximal length (refer to
installation manual). This is true for all generators, but
specially for the Whisper 3,5, because this small engine
has a small gas flow that easily can be blocked by a water
trap in the exhaust system. When any doubt;
backpressure has to be measured. An easy way to
measure for back-pressure is to use a water column. A
water column can be made visible in a plastic tube along a
yardstick and fitting the end to a hose connection to fit in
the adaptor on the injection bent after removing the
exhaust temperature switch. The bent A hanging down
should not be to short helping to damp the pulsating effect
of the gas discharge that is characteristic for a one
cylinder engine. The water column should be no more than
24 inches (60 cm.) of water (0,87 PSI - 0,06 bar)
1 Varistor
(420V);
2
EMC capacitors (4,7nF - 630V);
3
Diodes (25A - 1200V).
Fig15
Fig16: Setting assembly