Friedrich 2008 - Manual (Page 22)

CAPACITORS CAPACITORS
Many motor capacitors are internally fused. Shorting
the terminals will blow the fuse, ruining the capacitor.
A 20,000 ohm 2 watt resistor can be used to discharge
capacitors safely. Remove wires from capacitor and place
resistor across terminals. When checking a dual capacitor
with a capacitor analyzer or ohmmeter, both sides must
be tested.
Capacitor Check with Capacitor Analyzer
The capacitor analyzer will show whether the capacitor
is “open” or “shorted.” It will tell whether the capacitor
is within its micro farads rating and it will show whether
the capacitor is operating at the proper power-factor
percentage. The instrument will automatically discharge
the capacitor when the test switch is released.
Capacitor Connections
The starting winding of a motor can be damaged by a
shorted and grounded running capacitor. This damage
usually can be avoided by proper connection of the
running capacitor terminals.
From the supply line on a typical 230 volt circuit, a 115 volt
potential exists from the “R” terminal to ground through a
possible short in the capacitor. However, from the “S” or
start terminal, a much higher potential, possibly as high as
400 volts, exists because of the counter EMF generated
in the start winding. Therefore, the possibility of capacitor
failure is much greater when the identified terminal is
connected to the “S” or start terminal. The identified
terminal should always be connected to the supply line, or
“R” terminal, never to the “S” terminal.
When connected properly, a shorted or grounded running
capacitor will result in a direct short to ground from the “R”
terminal and will blow the line fuse. The motor protector will
protect the main winding from excessive temperature.
ELECTRIC SHOCK HAZARD
WARNING
Turn off electric power before servicing.
Discharge capacitor with a 20,000 Ohm 2 Watt
resistor before handling.
Failure to do so may result in personal injury,
or death.
20
Dual Rated Run Capacitor Hook-up
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