Introduction:
In a dynamometer type wattmeter, the coil that is split into two parts is the Current Coil.

Explanation:
The dynamometer type wattmeter is a type of instrument used to measure the power in an electrical circuit. It is based on the principle of the interaction of magnetic fields produced by the current and voltage in the circuit.

Working:
The wattmeter consists of two coils, namely the Current Coil and the Pressure Coil (also known as the Potential Coil). The Current Coil is connected in series with the load and carries the load current, while the Pressure Coil is connected across the load and carries the load voltage.

When the load is connected to the wattmeter, the load current passes through the Current Coil, while the load voltage is applied across the Pressure Coil. The two coils are placed perpendicular to each other to create a magnetic field.

Current Coil:
The Current Coil is split into two parts to allow for the passage of the load current. The split Current Coil ensures that the entire load current flows through it, thereby generating a magnetic field proportional to the load current.

Pressure Coil:
On the other hand, the Pressure Coil remains intact and is not split into two parts. It is connected across the load and carries the load voltage. The magnetic field generated by the load voltage interacts with the magnetic field produced by the Current Coil.

Interaction of Magnetic Fields:
The interaction of the magnetic fields causes a torque to be exerted on the moving element (usually a lightweight aluminum disc) of the wattmeter. The torque is proportional to the product of the load current and voltage, which represents the power being measured.

Measurement of Power:
The torque exerted on the moving element is opposed by a controlling torque, usually provided by a spring. The deflection of the moving element is proportional to the power being measured, and it can be calibrated to directly indicate the power in watts.

Conclusion:
In a dynamometer type wattmeter, the Current Coil is split into two parts to allow for the passage of the load current. This split design ensures that the entire load current flows through the Current Coil, facilitating accurate measurement of power.