Selecting Capacitors - Tecumseh AH5540E Service Handbook

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SERVICE HANDBOOK
FIGURE 3-16: Potential type relay mounting positions.

Selecting Capacitors

Never use a capacitor with a lower voltage rating than that specified. A higher voltage rating than
that specified is acceptable.
Start Capacitor Bleeder Resistors
Modern high power factor, low current single-phase compressor motors which required
start and run capacitors used with potential type relays can created electrical circuits which
could cause starting relay damage resulting in compressor failure.
The high voltage stored in the start capacitor could discharge across the contacts of the
starting relay thus welding them and preventing the relay from functioning. Capacitor fail-
ure and/or starting winding failure could result.
To eliminate this, Tecumseh Products Company start capacitors are equipped with bleeder
resistors wired across the capacitor terminals. No start capacitor used in conjunction with
a potential relay and run capacitor should be installed without such a bleeder resistor.
In an emergency where no bleeder resistor equipped capacitors are available, a two watt
15,000 ohm resistor can be obtained and soldered across the capacitor terminals. See
Figure 3-17.
Start Capacitor Substitution
If the specified start capacitor is not available, the next larger sized MFD capacitor at the
same or higher voltage rating may be used. Do not add excessive starting capacitance.