Alternator And Components; Description Of Alternator - Piper SENECA II Service Manual

PIPER SENECA II SERVICE MANUAL
The circuit breaker panel contains two 5 ampere circuit breakers marked ALT FIELD left and right. If
the field circuit breakers trip, it will result in a complete shutdown of power from the particular generating
system. After a one or two minute cool-down period, the breakers can be reset manually. If tripping
reoccurs and holding the breakers down will not prevent continual tripping, then a short exists in the
alternator field.
Unlike previous systems, the ammeters do not indicate battery discharge but displays the load in
amperes placed on the particular generating system. With all electrical equipment off (except master), the
ammeters will indicate the amount of charging current demanded by the battery. This amount will vary,
depending on the percentage of charge in the battery at the time. As the battery becomes charged, the
amount of current displayed on the ammeters will reduce to approximately two amperes. The amount of
current shown on the ammeters will tell immediately whether or not the alternator systems are operating
normally if the following principles are kept in mind.
NOTE
The amount of current shown on the ammeter is the load in
amperes that is demanded by the electrical system from the
alternator. As a check, take for example a condition where the
battery is demanding IO amperes charging current; then switch on
the anti-collision light. Note, the value in amperes placarded on
the panel for the anti-collision light circuit breaker ( 10 amps) and
multiply this by 80 percent; you will arrive at a current of 8
amperes. This is the approximate current drawn by the
anti-collision light. Therefore, when the anti-collision light is
switched on, there will be an increase of current from 10 to 18
amperes displayed on the ammeter. As each unit of electrical
equipment is switched on, the currents will add up and the total,
including the battery, will appear on the ammeter.
11-5. ALTERNATOR AND COMPONENTS.
11-6. DESCRIPTION OF ALTERNATOR. The principal components of the alternator are the brush
holder assembly, the slip ring end head, the rectifiers, the stator, the rotor and the drive end head.
a. The brush and holder assembly contains two brushes, two brush springs, a brush holder and
insulators. Each brush is connected to a separate terminal stud and is insulated from ground. The brush and
holder assembly can easily be removed for inspection or brush replacement purposes.
b. The slip ring end head provides the mounting for the rectifiers and rectifier mounting plate,
output and auxiliary terminal studs, and the brush and holder assembly. The slip ring end head contains a
roller bearing and outer race assembly and a grease seal.
c. The rectifiers used in these units are rated at 150 peak inverse voltage (PIV) minimum for
transient voltage protection. Three positive rectifiers are mounted in the rectifier mounting plate while the
three negative rectifiers are mounted in the slip ring end head. Each pair of rectifiers is connected to a
stator lead with high temperature solder. The stator leads are anchored to the rectifier mounting plate with
epoxy cement for vibration protection.
Reissued: 10/11/79
ELECTRICAL SYSTEM
2F23