Because of this complexity, a generic relay diagram will not work. You need the specific Qp3-12a wiring diagram for your model variant. The most common variants include:
Think of the QP3-12A as a heavy-duty switch that is controlled by electricity. You cannot manually flip the switch; instead, you send a small electrical signal to the "coil." This coil creates a magnetic field that snaps the main contacts together, allowing high-voltage electricity to flow to your motor, heater, or lighting bank.
: Typically the right-side pin. This pin remains energized while the compressor is operating. Technical Specifications
Many QP3-12A configurations (like the J1 or J4 variants) include terminals for a Run Capacitor
: Usually the top pin in the triangle. The overload protector portion of the QP3-12A connects here to monitor for overheating.
Before diving into the wiring diagram, it is essential to understand exactly what the QP3-12A is and what role it plays in an electrical circuit.
If you have the Qp3-12a current monitoring version, the wiring diagram changes: L1, L2, L3 pass through an internal current transformer. You then program a threshold. If current drops below the threshold (dry run), the relay trips.
