SDMO R33C3, User And Maintenance Manual

Page: 225 / 244

Installation and maintenance
R250
A.V.R.
4067 en - 2009.05 / b
LEROY-SOMER
9
3.3 - Electrical faults
Warning: after setting-up or trouble-
shooting, replace all access panels or
covers.
Fault Action Effect Check/cause
No voltage at
no load on
start-up
Connect a new battery
of 4 to 12 volts to
terminals E- and E+
respecting the polarity
for 2 to 3 seconds
The alternator starts up and its
voltage is still correct when the
battery is removed.
- Lack of residual magnetism
The alternator starts up but its
voltage does not reach the rated
value when the battery is
removed.
- Check the connection of the voltage
reference to the A.V.R.
- Faulty diodes
- Induced short circuit
The alternator starts up but its
voltage disappears when the
battery is removed
- Faulty A.V.R.
- Exciter field short-circuited
- Short-circuit in the main field. Check the
resistance
Voltage too
low
Check the drive speed
Correct speed
Check the A.V.R. connections (A.V.R. may
be faulty)
- Field windings short-circuited
- Rotating diodes burnt out
- Main field winding short-circuited
- Check the resistance
Speed too low
Increase the drive speed
(Do not touch the A.V.R. pot (P1) before
returning to the correct speed.)
Voltage too
high
Adjust A.V.R.
potentiometer
Adjustment ineffective
- Faulty A.V.R.
- 1 faulty diode
Voltage
oscillations
Adjust A.V.R. stability
potentiometer
- Check the speed: possibility of cyclic
irregularity
- Loose terminals
- Faulty A.V.R.
- Speed too low on load
(or U/F gradient set too high)
Voltage
correct at no
load and too
low when on
load (*)
Run at no load and
check the voltage
between E+ and E- on
the A.V.R.
- Check the speed (or U/F gradient set too
high)
- Faulty rotating diodes
- Short-circuit in the main field. Check the
resistance
- Faulty induced excitaion
(*) Warning: For single-phase operation, check that the sensing wires coming from the A.V.R. are correctly connected to
the operating terminals (see the alternator manual).
Voltage
disappears
during
operation
Check the A.V.R., the
surge suppressor, the
rotating diodes and
replace any defective
components
The voltage does not return to the
rated value
- Exciter winding open circuit
- Faulty induced excitation
- Faulty A.V.R.
- Main field open circuit or short-circuited
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