Standard set of information for any transformer requirement

Transformers come in all shapes and sizes, and there are many different types of transformers that suit different needs. Transformers can be custom designed by professionals to meet the customers’ needs and requirements specified or purchased from among the stock.

Buying a transformer can be a little daunting if you do not know what you are looking for because transformers can come with several different specifications, including design, requirements for installation etc.

This page provides direction for people interested in submitting their transformer requirements. The following list describes each specification our engineers will request.

There are some key features of the transformers that need to be considered before purchasing the transformers. The following are some of the essential electrical parameters:

Input Voltage

This is the amount of voltage applied to the terminals of the primary winding of the transformer. If this is the voltage coming from your wall power outlet, it would likely be 110-120 volts (for North America) or 220-240 volts (for much of the rest of the world). North American industrial applications often use 220, 240, or 277 volts.

Input Voltage

Input Voltage is the amount of voltage applied to the terminals of the primary winding of the transformer. If this is the voltage coming from your wall power outlet, it would likely be 110-120 volts (for North America) or 220-240 volts (for much of the rest of the world). North American industrial applications often use 220, 240, or 277 volts.

Input Frequency

Input Frequency is the frequency of the voltage applied to the terminals of the transformer’s primary winding. If your input power comes from your wall outlet, the likely input frequency would be 50 Hz (in India/Europe) or 60 Hz (North America).

Output Voltage

Output Voltage is the amount of voltage supplied by the transformer to the applied equipment. The equipment to be powered by the transformer will typically require a specific voltage and current for proper operation.

Output Current

Output Current is the amount of amperage supplied by the transformer to the applied equipment. The output current (along with the output voltage) determines the output power.

Output Power (often referred to as “VA”)

Output Power is the output voltage multiplied by the output current. It is the main determining factor for the transformer’s physical size (the more significant the output power, the larger the physical size—for similar construction types).

Because the voltage and current of the secondary circuit may not be in phase, the actual power delivered to the load may be lower than the VA (apparent power) rating.

Physical Size Requirements

As you would expect, there is a limit to how small a manufacturer can build a transformer for a required output voltage and current. However, different configurations may allow manufacturers to change the shape of the transformer so it might fit the available space or enclosure.

Estimated Annual Usage

This information is good to know because it helps us determine material and price. As you would expect, the cost-per-transformer is likely to decrease with a higher annual usage amount.

Mounting Method

The mounting method is the preferred way the transformer will be attached to the equipment, and there are three standard methods:

Chasis Mount

The transformer frame is mounted directly to the equipment, either by its frame or an attached bracket.

PCB Surface Mount

The transformer is mounted on a printed circuit board with pads (or feet) that are soldered directly to the board’s surface.

PCB Through-hole Mount

The transformer is mounted on a printed circuit board with soldered pins that protrude through the board.

Termination Type

Termination type is the preferred way the input and output windings will be terminated. The equipment to be powered by the transformer may also require a specific type of termination. Shreejee Electronics commonly configure the following termination types:

Wire Leads

Input and output lead wires are cut and stripped to desired lengths

Quick Connects

The transformer has tinned-brass tabs of the desired size that are designed for quick connection/disconnection.

Terminal Board

The transformer has tinned-brass tabs of the desired size that are designed for quick connection/disconnection.

Inline Connectors

The transformer leads are crimped to connectors inside plastic housings, which then fit mating connectors on the applied equipment.

Bolt Terminals

The transformer has individual brass or stainless-steel bolts (usually 10-32 or ¼-20 size), one for each input and output lead. Bolt terminals are often the preferred termination method for power transformers over 2 KVA.

Solder Lugs

The transformer has tinned-brass tabs with holes to fit your specified wire size for easy soldering connections.

Screw Terminals

The transformer has individual screw-connects, one for each input and output lead. Different types of terminals, such as finger-safe terminals (shown on the right), meet European standards.

Other Requirements

Copper Shielding Band

Some applications may require unique features, such as a Copper Shielding Band (as shown), to reduce transformer noise.

RoHS Compliance

RoHS compliance helps keep all listed hazardous substances out of the marketplace and restrict their use in production facilities.

As you may expect, our design engineers gather a standard set of information when taking transformer requirements. If you are unable to locate any of this information, we may help fill in the blanks. You’re always welcome to call in your specifications or send them to us through the Quote Request page.

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