Understanding Copeland Single Phase Compressor Electrical Connections Guide

Begin by identifying the run capacitor terminals–typically marked with C (common) and R (run). The herm wire from the motor’s start winding must connect directly to the Herm post on the capacitor. If the device lacks a start relay, use a potential relay with a 100–150 μF run capacitor for units under 1 HP. For larger models, verify the relay’s coil voltage matches the system’s line voltage (115V or 230V).

Attach the line power wires to the L (line) and N (neutral) terminals, ensuring the neutral connects to the capacitor’s common terminal. Ground the chassis by securing the grounding wire to the designated screw or terminal block. If the system includes an overload protector, route one motor lead through it before reaching the Common terminal on the contactor.

Check the schematic for thermal protection: most units integrate a bimetal disc or PTC thermistor in series with the start winding. If the device fails to start, measure resistance across the start and run windings–values below 0.5Ω or above 20Ω indicate a fault. Replace any damaged components before applying power.

For dual-voltage configurations, swap the connections between L1 and L2 for 230V operation. Ensure the relay’s Normally Closed (NC) contacts engage during startup–failure points to a defective relay. Use a multimeter in continuity mode to confirm proper switching before energizing the circuit.

Electrical Hookup Guide for Hermetic Motor Units

Begin by identifying the terminal block layout on your hermetic unit–standard models typically feature three posts labeled “C” (common), “S” (start), and “R” (run). For models rated below 1 horsepower, connect a 15-amp start capacitor between “C” and “S” using 14 AWG copper wire, ensuring the capacitor’s microfarad rating matches the manufacturer’s specification (±10%). Higher-capacity units may require an additional potential relay or current-sensitive starter; verify the relay’s pickup voltage (usually 75-85% of line voltage) before installation to prevent phase-locked rotor conditions.

Component	Wire Gauge (AWG)	Torque Specification (in-lbs)	Max Current Draw (A)
Common (“C”) Terminal	14	12-15	Varies by HP
Start (“S”) Terminal	14	12-15	Capacitor inrush +30%
Run (“R”) Terminal	12 (for >1 HP)	18-22	FLA x 1.25

For dual-voltage units (e.g., 115/230V), split the winding connections at the “C” post–use a jumper for 230V operation or separate leads for 115V. Always energize the run winding first during testing; delay start winding activation by 0.5-1 second to avoid back-EMF spikes. Replace factory-installed thermal protectors if resistance exceeds 3 ohms at room temperature, as degraded contacts risk overheating at the “C” terminal. Use a clamp meter to validate locked-rotor amperage post-installation–values should stabilize within 200 milliseconds; deviations indicate improper capacitor sizing or misaligned relay timing.

Locating Power and Control Points on Hermetic Units

Begin by inspecting the motor’s terminal block–typically a three-post arrangement labeled C (common), S (start), and R (run). Use a multimeter set to resistance mode; attach probes to C and R. Expect readings between 3–15 ohms for standard 1/6 to 3 HP models–any deviation signals winding damage. Compare measured values against the unit’s technical sheet, which lists exact ohms for each winding. If readings match but the motor fails to start, swap the start capacitor.

For models with a built-in overload protector, locate the disk-shaped component adjacent to the terminals–often black or gray with two wires exiting it. Disconnect power, then probe across its contacts; infinite resistance indicates an open protector needing replacement. Check the capacitor by disconnecting its leads and testing capacitance with a dedicated meter. Acceptable ranges vary by tonnage: 20–45 μF for 1/4 HP, 88–108 μF for 2 HP. Replace capacitors showing zero or bulging casings immediately.

• Dual-voltage motors add a fourth terminal (L)–labelled wires split to accommodate both 115V and 230V configurations.
• Always discharge capacitors before handling, using a 20,000-ohm resistor across terminals for 30 seconds.
• Relay types (potential or current) dictate start winding engagement; identify by model code (e.g., RHP, TLC) printed on the shell.

External Relay and Start Kit Wiring

Hard-start kits link between C–S posts, substituting for internal relays if missing. Mount solid-state relays within 6 inches of the motor to prevent voltage drop. For potential relays, connect the brown wire to L or line voltage post, not ground–mismatched connections destroy the coil. Current relays fit over the R terminal; ensure the arrow points toward the windings and torque screws per manufacturer specs (usually 12–15 in-lb).

1. Verify line voltage matches nameplate specs before energizing.
2. Inspect all connections for tinning, oxidation, or fraying–sand oxidization off copper strands.
3. Route auxiliary wires separate from high-current lines to reduce interference.

Step-by-Step Connection Guide for Standard Voltage Setups

For 115V models, connect the line voltage to terminals L1 and N, ensuring the run capacitor bridges C and Herm terminals. Verify polarity before energizing–reverse connections may cause irreversible damage to the motor windings within seconds. Use 12-gauge wire for currents exceeding 8A to prevent overheating.

Dual-Voltage (230V/208V) Configuration

Link L1 and L2 to separate voltage sources, leaving the neutral disconnected. Jumper the Common and Run terminals internally if required–refer to the unit’s labeling or a 6-pin terminal map for exact positions. For 208V setups, reduce capacitor microfarad ratings by 10% to compensate for lower voltage stress. Always use a multimeter to confirm voltage stability (±5%) before finalizing connections.

Ground the chassis using a dedicated 10-gauge copper wire, securing it to the designated screw terminal marked ⏚. For hermetic units, ensure the overload protector’s reset position aligns with Herm–misalignment risks premature failure under load. Test run conditions by monitoring amperage draw: deviations beyond 15% of nameplate values indicate incorrect capacitance or voltage mismatches.

Troubleshooting Overload Protector and Start Relay Connections

Check the thermal disc resistance across the overload protector terminals using a multimeter set to ohms. A functional unit will read near zero ohms at ambient temperature; a reading above 2Ω indicates a faulty disc requiring replacement. For PTC relays, measure resistance between the start and run terminals–values below 1Ω or above 100Ω signal a failed relay. Verify the starting capacitor’s microfarads with a capacitance meter; deviations beyond ±10% of the labeled value confirm deterioration.

Inspect connections for oxidation or loose crimps:

• Scrape corroded terminals with fine-grit sandpaper until shiny, then re-tighten to 10-12 inch-pounds.
• Test relay socket continuity–no reading between socket and terminal means a broken internal contact.
• Check for voltage drop across relay contacts during startup (should not exceed 0.2V); higher values indicate carbon buildup or worn contacts.
• For units tripping repeatedly, measure compressor winding resistance (start to run should match manufacturer specs within 5%).

Reset manual overload protectors by waiting 30 minutes for cooling–if tripping persists, replace the protector before further diagnostics.

Key Circuit Variations in CSIR vs. PSC Hermetic Motor Configurations

Always connect the CSIR motor’s start winding through a relay–never hardwire it directly to the power source. The current-sensitive potential relay (typically 14–18 ohms) engages only during startup, cutting out when rotor speed reaches 75–80% of synchronous RPM. Failure to use a relay risks burning the auxiliary coil, which carries 4–6x the locked rotor amps (LRA) of the run winding. Measure relay coil resistance before installation; deviations above ±5% indicate internal damage.

PSC designs eliminate the start relay entirely, relying on a run capacitor (usually 15–30 µF) to create the phase shift needed for torque. The capacitor remains in series with the start winding continuously, reducing inrush current by 30–40% compared to CSIR. Capacitor voltage rating must exceed system peak voltage by at least 25%; a 370V rating suffices for 230VAC systems, while 400V is mandatory for 240VAC. Organic film capacitors degrade faster under heat–replace if capacitance drops below 90% of rated value.

Terminal Block Arrangements

CSIR units expose three terminals: common (C), run (R), and start (S). The relay connects to terminals R and S, with the common jumper linking to the capacitor’s opposite side. Miswiring R and S reverses rotation in scroll models; verify direction within 5 seconds of startup to prevent oil pump starvation. PSC variants usually consolidate to two terminals (C and R), with the capacitor wired across them. Some PSC twin-cylinder models retain a third terminal for a dual-capacitor setup–check the data plate for µF values before reconnecting.

Overload protection placement differs fundamentally. CSIR motors integrate the device internally (Klixon or bimetal disk) in series with the common terminal, tripping at 120–150% of full load amps (FLA). PSC units often rely on external protectors–either clip-on bimetal discs or PCB-mounted PTC thermistors–mounted on the motor shell or discharge line. Ensure protector contacts cleanly open; oxidation can cause nuisance tripping at currents as low as 1.1x FLA.

Run capacitor wiring polarity is irrelevant for AC operation, but physical orientation matters. Mount capacitors vertically in outdoor units, with the vent facing downward to prevent moisture accumulation. Terminals should align with the motor’s axis of rotation–side-mounted capacitors can vibrate loose within 2,000 operating hours. Use 14 AWG stranded copper wire for all connections; solid wire fatigues at vibration nodes and can fracture under thermal cycling.

Voltage and Phase Shift Calculations

PSC motors on 230V systems require a phase shift of 80–90°, achieved with precise capacitance: 3.3 µF per 100W for standard efficiency, 4.2 µF per 100W for high-torque designs. CSIR motors need no fixed phase shift, but start capacitors (100–300 µF) must match the relay’s pickup voltage (usually 70–85% of line voltage). Use a clamp meter to verify capacitor current during startup; readings below 60% of calculated value indicate a weak capacitor or relay failure.

Neutral connections are forbidden in both types–all current must return through the run winding. Test for ground faults with a 500V megohmmeter; insulation resistance below 1MΩ mandates motor replacement. For CSIR models, disconnect the relay before megger testing to avoid damaging the coil. PSC units with internal thermal protectors may show false continuity if tested while hot–allow the motor to cool to ambient before diagnostics.