Friedrich R-410A service manual Component Testing, Capacitor Check with Capacitor Analyzer

COMPONENT TESTING

FAN MOTOR

A 230 volt single phase permanent split capacitor motor is used to drive the evaporator blower and condenser fan. A running capacitor is wired across the start and run terminals of the motor.

The motor is totally enclosed and is protected with a line voltage overload located internally of the motor. The motor shaft is stainless steel to resist corrosion. When the unit is turned on, the motor runs continuously.

FAN MOTOR

WARNING

ELECTRIC SHOCK HAZARD

Disconnect power to the unit before servicing. Failure to follow this warning could result in serious injury or death.

FAN MOTOR – TEST

1.Determine that the capacitor is good.

2.Perform continuity test on windings to determine if open, shorted or okay.

SOLID STATE RELAY

Two 50 amp rated 208/230 volt solid state relays are used to energize the compressor and fan motor. Terminals 3 and 4 are the 208/230 volt line side. Terminals 1 and 2 are load side contacts.

Line side

SOLID STATE

RELAY

Load

side

LED indicates contacts closed when lit

SYSTEM CONTROL SWITCH

This switch is double pole, single throw. Check for continuity between terminals 2 and 3, and 5 and 6.

SWITCH, ON-OFF

CAPACITORS

WARNING

ELECTRIC SHOCK HAZARD

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.

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 identifi ed terminal is connected to the “S” or start terminal. The identifi ed 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.

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