# Commercial transformers for variable frequency & voltage

• jimmydmallow
In summary, the conversation discusses the need to step up the voltage of a 3-phase PM generator with variable AC output. The desired step up ratio is between 1:1.5 and 1:2, but most commercial transformers have defined input voltage and frequency. It is suggested to use a readily available 50 Hz transformer and to be aware of the reactance and power transfer issues at lower frequencies. Depending on the frequency, a larger transformer may be needed. This is similar to the use of 400 Hz in aircraft to reduce transformer size.
jimmydmallow
I am looking to step up the voltage of a 3 phase PM generator which has variable AC output of 200 - 400 Vl-l, and 15 - 30Hz. I am looking for a step up ratio between 1:1.5 and 1:2, and need this transformer to be a commercial device.

What i have been finding is that most commercial transformers have defined input voltage and frequencies (i.e. 240/480 V, 60Hz), which is not ideal of course.

Does anybody know of commercial devices for this type of application? I have considered back to back VFDs but that seems overly complicated.

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Consider using a readily available 50 Hz (or use 60 Hz and de-rate even more) transformer. Be aware that you will need to determine your Reactance of the Transformer and then de-rate it to the lowest frequency it will see. Transformers have two impedance qualities, one is simple resistance, the other is reactance. You can easily measure the resistance with an ohm meter. Most transformers have an x:r ratio of 5-7. However that is at 60 Hz. Remember to de-rate.
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What is really going on is that your transformer will burn up if it offers too little resistance to the primary side power. Since the reactance approaches zero as the frequency approaches zero, your transformer will carry larger currents than it should for the power transfer. So you will likely need a 4 X larger transformer at half the freq (I am not doing the math, but power is an i^2 issue. 2 x the current = 4 x the power. So if you thought you needed a 1 KVA transformer, but you are using a 60 Hz rated transformer in place of a need to use a 30 Hz transformer, you will need to use a 4 KVA xfmr for the application. And you will suffer from leakage due to lower frequencies for this inductor ie it will look more and more like a short circuit as the frequency goes from 30 to 15 Hz. If you operate at 15 Hz you will probably need a 16 KVA transformer (and probably suffer too much energy loss, again, you need to crunch the numbers to help you analyze your energy losses).
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The reason aircraft use 400 Hz is because they get to reduce the size of their on board transformers. By going in the opposite direction, you have to increase the size (or physically make your own, if you can't buy an off the shelf item).

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## 1. What is a commercial transformer for variable frequency and voltage?

A commercial transformer for variable frequency and voltage is a type of electrical transformer that is designed to change the frequency and voltage of an alternating current (AC) power supply. It is commonly used in industrial and commercial applications to convert the power from the main power grid to a frequency and voltage that is suitable for specific equipment or machinery.

## 2. How does a commercial transformer for variable frequency and voltage work?

A commercial transformer for variable frequency and voltage works by using electromagnetic induction to transfer electrical energy between two or more circuits. It consists of two or more coils of insulated wire, called the primary and secondary windings, that are wound around a common magnetic core. The frequency and voltage of the output can be adjusted by changing the number of turns in the windings or by using additional components such as capacitors or inductors.

## 3. What are the benefits of using a commercial transformer for variable frequency and voltage?

There are several benefits to using a commercial transformer for variable frequency and voltage, including improved efficiency, increased control over the output power, and the ability to power equipment and machinery that require different frequencies and voltages. It also helps to protect sensitive equipment from voltage fluctuations and can reduce energy costs by allowing for power factor correction.

## 4. What are some common applications for commercial transformers for variable frequency and voltage?

Commercial transformers for variable frequency and voltage are commonly used in a variety of applications, including motor drives, pumps, fans, compressors, and other industrial equipment. They are also used in renewable energy systems, such as wind and solar power, to convert the variable frequency and voltage of the energy source to a more stable and usable form.

## 5. How do I choose the right commercial transformer for my specific needs?

Choosing the right commercial transformer for variable frequency and voltage will depend on several factors, including the frequency and voltage requirements of your equipment, the power rating of the transformer, and any additional features or customization options that may be needed. It is recommended to consult with a qualified electrical engineer or supplier who can help you select the best transformer for your specific needs.

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