For V-curves for a synchronous motor the graph is drawn between

The correct answer is: B. terminal voltage and load factor.

A V-curve is a graph that shows the relationship between the terminal voltage and the load factor of a synchronous motor. The load factor is the ratio of the actual load to the rated load of the motor. The terminal voltage is the voltage that is applied to the motor terminals.

The V-curve is a useful tool for determining the operating characteristics of a synchronous motor. It can be used to determine the maximum load that the motor can carry, the minimum voltage that is required to operate the motor, and the efficiency of the motor at different loads.

The V-curve is also useful for troubleshooting synchronous motor problems. If the motor is not operating properly, the V-curve can be used to identify the cause of the problem.

Here is a brief explanation of each option:

• Option A: field current and armature current. The field current is the current that flows through the field winding of a synchronous motor. The armature current is the current that flows through the armature winding of a synchronous motor. The V-curve does not show the relationship between the field current and the armature current.
• Option B: terminal voltage and load factor. The terminal voltage is the voltage that is applied to the motor terminals. The load factor is the ratio of the actual load to the rated load of the motor. The V-curve shows the relationship between the terminal voltage and the load factor.
• Option C: power factor and field current. The power factor is the ratio of the real power to the apparent power. The field current is the current that flows through the field winding of a synchronous motor. The V-curve does not show the relationship between the power factor and the field current.
• Option D: armature current and power factor. The armature current is the current that flows through the armature winding of a synchronous motor. The power factor is the ratio of the real power to the apparent power. The V-curve does not show the relationship between the armature current and the power factor.