Transformers

Are control transformers the same as power supplies?

When looking for one or the other, customers frequently confuse transformers and power supplies. These two technologies are related but have very different applications. Power supplies and converters are more process-based and use multiple parts to convert AC to DC, including transformers at times. So, technically, these devices may have transformers but, due to the nature of the operation, they are not transformers.

What to consider when selecting control transformers?

Before selecting a control transformer, three circuit characteristics must be determined. Sealed VA, inrush VA, and inrush load power factor are the three characteristics. The sealed VA is the amount of power (in VA) that the transformer must deliver to the load over a long period of time. The inrush VA is the amount of power (in VA) that the transformer must deliver to the load when it first turns on. The inrush VA is frequently ten times the sealed VA. The power factor of the inrush current is the inrush load power factor. The inrush load power factor is difficult to calculate, but 40% is a safe bet in most cases.

Can a transformer be used at higher frequencies?

A transformer designed for 50/60Hz operation can operate at frequencies as high as 400Hz. However, the inrush capability will be reduced at 400Hz.

What effect does a control transformer have on electrical disturbances found on the line?

A control transformer, because it has primary and secondary windings, will provide some tidy up in terms of electrical noise, spikes, surges, and transients. However, a control transformer will not provide the same level of power conditioning as products designed for that purpose.

Can a control transformer regulate the output voltage?

No, a control transformer does not control voltage. The output voltage is determined by multiplying the coil's turn ratio by the input voltage.