Measuring For Excessive Voltage Drop; Troubleshooting Potential Relay; Troubleshooting Start Capacitor (Black Plastic Casing); Troubleshooting Run Capacitor (Metal Casing) - Traulsen G Series Service Manual

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6.2.7

Measuring for Excessive Voltage Drop:

Now that the compressor has cooled down, measure the voltage supplied to the cabinet while the compressor

is trying to start. If the voltage drops below 104 volts, you may have a problem with the power supply, try a

different circuit.

Disconnect power supply, remove wires and measure for continuity between pins 1 & 2 (Normally Closed

Contacts) of Potential Relay. If continuity is not detected replace potential relay. See Table 14 for part number.

Clamp amp probe onto blue wire connected to pin number 1 of the Potential Relay. Apply power and measure

the current. If the current does not drop out after compressor starts, then the contacts between pins 1 and 2

are stuck in the closed position. In this case the potential relay must be replaced. See Table 14 for part number.

If the voltage measures 115 Volts +/- 10% but the compressor doesn't start, measure the current with your amp

meter at the common terminal of the compressor. If the current spikes very high but the compressor doesn't

start, disconnect power so that you can remove all the start components for testing. Start capacitors can be

tested with a microfarad tester. For the most accurate measurement remove the resistor from the start

capacitor. (The start capacitor should never be used without the resistor as this will damage the start relay.)

If microfarads measured do not match values in table below, replace start capacitor. See Table 13 for specs and

part number for start capacitor.

If the compressor starts and runs with an amp draw higher than the RLA and the compressor is a capacitance

run compressor (which means it requires a run capacitor), disconnect power so that you can remove the run

capacitor from the circuit for testing with a microfarad tester. Connect the microfarad tester across both

terminals of the run capacitor. See Table 13 for specs and part numbers for run capacitors. If the microfarads

measured do not match specs given, replace the run capacitor.

Note: If the run capacitor is swollen or leaking fluid, replace run capacitor.

Figure 51: Potential Relay Schematic

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