TRANSFORMER REWINDING and REPAIR SERVICE

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  • Page Updated 06 Aug 2019.

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.

Prices for valve transformer re-varnish (from Aug 2019):

  • HT transformers, HT chokes, SE and PP transformers up to 4 inch cube 20.00 GBP including VAT and return carriage
  • HT transformers, HT chokes, SE and PP transformers from 4 inch cube to 6 inch cube 50.00 GBP including VAT and return carriage

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. Please make sure that you have enclosed your name and address, email (if available), telephone number (if available) and any other useful information such as which connection is which and what equipment it came from.
If you do not include your details we will retain the transformer for a reasonable time then recycle it.
We do not accept liability for this action.

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.

Warnings

  • 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), NOT LOPT.

We can NOT rewind the following:
  • Motors (except clock motors and simple record player 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:
  • Leak Amplifier HT and Output transformers (various models).
  • Pye Black Box Record Player HT and Output transformers (various models).
  • Guitar amplifier output transformer (e.g., VOX, Fender, Gibson etc).
  • Telequipment D66A Oscilloscope EHT transformer.
  • Wurlitzer HT transformer (and other Juke box transformers).
  • Clock motor.
  • Test system multiple output transformer.
  • Cossor 1035 bitumen potted EHT transformer.
  • Industrial machine control transformer.
  • AR88 transformers.
  • Bush TV22 Frame 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).

Prices for valve transformer rewinds (from Aug 2019):

  • HT transformers, HT chokes, SE and PP transformers up to 3 inch cube 80.00 GBP including VAT and return carriage
  • HT transformers, HT chokes, SE and PP transformers from 3 inch cube to 4 inch cube 120.00 GBP including VAT and return carriage
  • HT transformers, HT chokes, SE and PP transformers from 4 inch cube to 6 inch cube 180.00 GBP including VAT and return carriage

© 2019 Variable Voltage Technology Ltd. Document Number DCW12872.
Issue Number: 12 - Dated: 06 Aug 2019 - FRACAS: X50599 - Release: Y11603.