POWER TRANSFORMERS - Frequently Asked Questions

A step-up transformer converts a low voltage to a high voltage. Often 110V up to either 240V or 415V. Step-up transformers are less common, but we do manufacture them at Transpower, and can also offer a portable 3kVA step-up tool/site transformer from stock. 

A step-down transformer converts a high voltage to a lower voltage. Often either 240V or 415V down to 110V. Step-down transformers is what we mostly produce at Transpower.

Also known as an isolation transformer. Most of the transformers we make are double-wound, but not all. Double-wound transformers work on the principle of mutual inductance; they have a primary and secondary coil and a change in the current of one coil will affect the current and voltage on the second coil, even if they are not touching. Because the two coils are not touching (i.e. isolated from each other) there is some protection against power surges. With a double-wound transformer, step-up is achieved by having more coils in the secondary (output) coil, while step-down is achieved by having more coils in the primary (input) coil.

Auto-wound transformers use a single coil, which acts as both the primary and secondary winding, so there is no isolation of the input and output, and consequently no protection from power surges. Auto-wound transformers can become step-up or step-down, by ‘tapping’ the coil at a certain point. All our auto-wound transformers are custom-build, so please ask for details and we would be happy to advise further.  

Intermittent/tool rated transformers cannot be used continuously, they are only suitable for use in short bursts. Some intermittent tool-rated transformers can be operated continuously, at a lower power. We can supply a range of intermittent/tool rated workshop & site transformers. If you need further advice on this, please ask.

A continuous transformer allows for exactly what it suggests, continuous use. We can supply continuous transformers as site, workshop, distribution and panel transformers.

We mainly work from 12VA to 15kVA (single phase) and up to 45 kVA (three phase) but we can actually supply transformers in up to 500 kVA. We can also custom-build maintenance panels with integral transformers at the Ceenorm site in Telford. Please ask us for more information and someone from our custom-build division will be happy to advise. 

Yes, we can custom build bespoke transformers to suit exact requirements, and our knowledgeable team can help you work out what that requirement is if needed. Whether it is intermittent or continuous rated, a step-down transformer or a step-up transformer, and isolation (double-wound) or an auto-wound transformer, we can help with your needs. 

Single or three phase transformers are certainly the most common, but we can also manufacture two-phase transformers if required. Ask us for further information. 

Some of our low-voltage power transformers are supplied from stock, others are made to order in just a few days (normally 3-5 days depending on how busy we are). And some low-voltage power transformers are custom built/bespoke builds, with a lead time of 3-5 days once the final specification for the bespoke transformer has been agreed. 

As well as low-voltage power transformers we can supply 110V junction boxes and 110V & 240V extension leads. Ceenorm (owners of Transpower) can supply a wide range of industrial plugs & sockets, electricians' tools and more. We also have a custom build team in Telford who specialise in custom built distribution units/equipment. And Cablecaddy, which is also owned by Ceenorm, can supply a wide range of industrial cable reels under the popular Marcaddy brand - including IP65-rated cable reels for outdoor use.  

Yes, our manufacturing site is ISO9001-2015 accredited (as is the Ceenorm manufacturing site in Telford). You can download a copy of our ISO9001-2015 certificate below.