• Page Updated 31 Jul 2017.

Low cost transformer recovery

  • Old transformers may be treated with wax which either melts out or dries.
  • Old transformers may not be treated at all.
  • Some manufacturers just used tape or paint to seal laminations.
  • Some transformers are in equipment which has been kept in damp conditions for years.
  • Attempts to clean old equipment may result in condensation within transformer windings.
  • All of the above may result in leaky, unsafe and noisy transformers.

The solution to this is to send us the transformer (UK only) and we will bake, vacuum varnish impregnate (twice) and test for safety.

We can do this for a fixed price of 20 GBP per transformer plus return delivery and packing of 16.95 GBP per parcel (up to 15Kg) plus VAT.

A comprehensive investigation and replacement and rewinding service is available.
The list below shows the sequence of operations. Each of these items has a cost depending the state of the original transformer.
We have succesfully rewound items from pre-war to present.
We can make further copies of the original (subject to parts availability).
Check our NEWS page to find out lead times for rewinding etc.

Note: This service is only available in the UK.
Please do not send us dead transformers without checking with us first.

Check our NEWS page to find out lead times for rewinding etc.

When you send us transformers please ensure that they are packed securely. Pack each transformer in a separate carton within an outer box. DO NOT USE 'large bubble' packaging as we have received several transformers damaged when the tags punctured the bubbles.

Our pricing structure for rewinds reflects the considerable work involved in investigating and rewinding transformers.
This will allow us to give rewinding the time it deserves and reduce the waiting list.
Check our NEWS page to find out lead times for rewinding etc.

Price confirmation and feasibility indication.
We can now provide an initial estimation of feasibility base on a simple question and answer sequence.
At the end of that sequence we can tell you if we may be able to do the rewind and a first estimate of price.
We cannot guarantee to complete the rewind until we done a full examination of the transformer.
Check our NEWS page to find out lead times for rewinding etc.


  • Examination of the transformer may result in unrepairable damage.
  • Part of the price is used for examination and preparation of reports.
    This is paid at the time of receipt of the transformer.
  • Following the report it may be decided that work cannot proceed.
  • A report of work to date and feasability is available and the remains will be returned.
    The initial payment for examination will be retained.

Sequence of operations

  • Specification and circuit appraisal (if available).
  • Dismantling and post mortem investigation (if possible).
  • Re-design check against specification and any other information.
  • Determine compliance with safety.
    This will be to current requirements if possible.
    If not then this will be to safety requirements in force at the time of original manufacture.
  • Remanufacture using original parts if possible.
    Rewinds are hand made and will normally have to wait for suitable time slot.
  • Test to confirm design and to meet safety requirements.
    Rewinds may need a special test configuration.
    There may be a delay while this is made available.

We CAN rewind the following - but see below for exceptions:
  • Valve Audio Output transformers
  • Valve HT transformers
  • Chokes and Inductors
  • Ferrite transformers
  • TV Frame transformers (FOPT)

We MAY be able to rewind the following - a extra charge is likely to cover dismantling and bobbin manufacture:
  • TV Line Output Transformers (LOPT) (bitumen or wax coated).
  • Hard potted or encapsulated transformers (limited success).

We can NOT rewind the following:
  • Motors (except clock motors).
  • Alternators.
  • Dynamos.
  • Generators.
  • Transformers of higher power than 1KVA (1000Watts).
  • Hard potted TV Line Output Transformers (LOPT).

This is a list of a few of the transformers that we have rewound or supplied replacements:
  • This list is to show the wide range of coils that we can wind. It is not a complete list.
  • Some of our standard products started off as rewinds.

  • Bush TV22 Frame output transformer.
  • Leak Stereo 20 HT Transformer.
  • Telequipment D66A Oscilloscope EHT transformer.
  • Wurlitzer HT transformer.
  • Aircraft EMC coils.
  • 2 KW Magnetron transformer.
  • Clock motor.
  • Test system multiple output transformer.
  • Potted SMPS EHT transformer.
  • Cossor 1035 bitumen potted EHT transformer.
  • Industrial machine control transformer.
  • Guitar amplifier output transformer.

Rewinds and Specials are fitted into design and production schedules when practical.
Standard product production will normally take priority.
This will result in an extended lead time if we have several rewinds or specials in at the same time.
For further details follow this link: News page (specials and rewinds lead time).

© 2017 Variable Voltage Technology Ltd. Document Number DCW12872.
Issue Number: 9 - Dated: 31Jul2017 - FRACAS: X50493 - Release: Y11290.