To get a control voltage of 120 VAC from a control transformer with a line voltage of 240 VAC, how should the primaries be connected?

Prepare for the SACA Electric Motor Control Systems 1 (C-202) Test. Utilize multiple choice questions and in-depth resources. Logical, structured insights for your success!

To achieve a control voltage of 120 VAC from a control transformer with a line voltage of 240 VAC, the primary windings of the transformer must be connected in series.

When transformers are connected in series, their voltages add up. In this case, if you have two transformers, each rated for 120 VAC, connecting them in series will provide a total of 240 VAC at the primary side. This allows the transformer to step down that 240 VAC to 120 VAC on the secondary side, which is the desired control voltage.

Connecting them in parallel would not be appropriate in this scenario, as that would only allow the transformer to handle the same voltage level while increasing the available current capacity, which does not accomplish the goal of stepping down the voltage to 120 VAC. The term "single configuration" typically refers to using only one transformer, which would not adequately handle the reduction of 240 VAC to 120 VAC without the proper connection method. Thus, the only viable method to obtain the required control voltage from a 240 VAC source is to connect the primaries in series.

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