Off load Tap Changer

How you should choose your right off load tap changer.

What is an Off Load Tap changer?

Tap changers are devices used in order to maintain a constant voltage in a transformer or to maintain within the prescribed limits.

An Off-load tap changer allows regulation of output voltage and through changes of taps in the transformer thanks to a control head. As the name suggest this type of changer requires that no load is connected to the transformer or that the transformer is de-energised completely before any switching manoeuvre.

Which type of Off Load Tap Changer to choose among those presented in our online catalog?

Our designer team can assist you in choosing your device. To that end, please fill out this form and send it back to us as an order to asp.commercial@appareils-precision.fr.

Or

Contact our sales department at asp.commercial@appareils-precision.fr and please give us the Tap changer range : HR / Cable / FII / HZ / HM / FII-HI / HI / HT (please consult the table)

- Maximum tension class / Maximum intensity

- HORIZONTAL alignment preferred : STAGE (DECK) Tap Changer (yes or no)

- VERTICAL alignment preferred : COLUMN Tap Changer (yes or no)

- Stage (Deck) or Column COUNT

- Group count per Stage or Column

- BRIDGE or DELTA (yes or no)

- One Output Per Group (or "LINEAR" or "Fixed Point" : yes or no)

- STAR connection (with or without neutral connection)

- Special diagram (to be detailed)

- For the above : NUMBER OF POSITIONS

- RATED CURRENT per Fixed Contact (A)

- Fixed contacts (FC) wire connection (Tubular (yes or no) / Flag for bolted lugs (available on FII/FII-HI/HI/HT)

- Control device configuration : Padlockable (yes or no) / Protect cover (yes or no) / Knob (yes or no) / Handle (yes or no) / Wheel (yes or no) /

- OTHER Control Device configuration (to be detailed).

Does ASP Company manufacture custom-made devices?

Yes, if you are looking for an Off Load Tap Changer with different characteristics from those presented in our online catalog, we will be able to design and manufacture it for you.

Indeed, we can make custom-made modifications on different parts of the device, such as:

- Dimensions

- Distance between phases

- Number of positions, phases and stages

- Localisation of the control device : Cover/wall/side wall of the transformer

Is it possible to use our Off Load Tap Changers in difficult weather conditions?

When the Transformer is used under difficult weather conditions such as in corrosive environments or in low temperatures (until -50°), we suggest the following:

- The aluminium parts located outside of the Transformer (steering wheel, handle, control unit…), can be provided with anodic oxidation and primary coat of paint.

- The steel parts located outside of the Transformer are zinc-plated by default. The can be provided in stainless steel.

- The O-rings are, by default, in Nitrile or in Viton (FPM). They can be provided in silicone.

What is the best way to maintain our Off Load Tap Changers?

It is recommended to operate Tap Changer once a year, several times on full range of taps, to make sure that any deposit is removed from the contact area.

In case annual maintenance is not possible, with Tap Changer having been unoperated during several years, it is requested to operate it about 20 times on full range of positions before changing of tap.

Measuring of resistance of phases, before and after above described self-cleaning maintenance operation, would be useful to check it’s efficiency.

Which types of oil are our devices compatible?

- Mineral Oils

- Synthetic Oils