How must the running windings of a dual-voltage motor be connected to operate on 120 V?

For a dual-voltage motor, the running windings must be connected in parallel to operate at the lower voltage, such as 120 V. When windings are connected in parallel, they provide a lower total resistance and allow more current to flow, which is suitable for operation at the reduced voltage. This arrangement ensures that each winding receives the full supply voltage, allowing the motor to function correctly under the intended operational conditions.

The parallel connection is essential because a series connection would increase the total resistance, which would not allow sufficient current to flow at 120 V, potentially leading to inadequate torque and inefficient motor performance. The terms "triad" and "in line" do not apply to the standard connections used for dual-voltage motors operating at 120 V, making them less relevant to this particular scenario. Thus, connecting the running windings in parallel is the proper method to ensure appropriate motor operation at the lower voltage.