ANG Voltage regulators

The A.N.G. autotransformer is an efficient, trouble-free device for controlling A.C. voltage.
Unlike most transformers, our voltage regulator has a transformation ratio that can be smoothly and continuously changed so the output of the unit can be controlled from zero to line voltage or even higher.

Below you will find the description and general specifications of the different models available, along with a glossary of the terminology used. You can skip directly to the technical specifications of the different series by selecting one of the two main categories below:



voltage regulator


  • Efficient – transforms power more efficiently than rheostats;

  • Durable – because it runs cool (40/50°C max);

  • Overloadable withstands 1000% overloads short term;

  • Independent of load size or power factor – voltage to the load changes little from full load to none;

  • Easy to control with simple raise-lower switches or standard process controllers. Motor drive control provides complete isolation between power and control circuits and ANG units are immune to power line noise;

  • Do not produce harmonic distortion;

  • Produce an adjustable output voltage that is a sine wave. Only the voltage magnitude is changed, the shape of the voltage is not distorted;

  • Handle all load power factors;

  • Can be used to adjust banks of capacitors and/or inductors;.


  • Regulate voltage (over and under-voltage testing of electrical and electronic equipment);

  • Speed control;

  • Lighting control in theaters, hotels, photographic studios;

  • Motor test stands;

  • Power supplies;

  • Industrial process heating control;

  • Source voltage & load banks for electrical testing: Circuit breaker – Uninterruptible power supplies – Generators

  • Control of D.C. voltage and current through rectifiers;

  • Control of rectifiers in electroplating etc.;

  • Supply voltage adjustment (automatic voltage stabilizers).


  • Manufacturing standards: Designed and tested according to VDE-0552 and IEC 61558-2-14; designed as toroidal autotransformer.

  • Core: All regulators use grain-oriented strip wound silicon steel cores ensuring low losses and reduce magnetizing current.

  • Windings: The winding, which is insulated from the core by precision molded winding formers, comprises a single layer (class H wire) carefully wound to provide a flat surface for the brush gear.

  • Brush gear: Easily replaceable carbon brush units are used, the resistance of the brush being carefully calculated to limit the current circulating in the bridged turns.

  • It is therefore most important that only the correct replacement brush is used. The ANG’s brushes are mounted in robust brush carriers insulated from the shaft, and designed so that metal parts cannot come into contact with the winding in the event of brush fracture.

  • Frames: The wound core and brush gear are mounted on a rugged cast aluminum frame providing strength combined with minimum weight. The bases incorporated mounting holes providing interchangeable fixing centers with many other variable autotransformers.


  • The data given in the table should be read in conjunction with the following general specifications.

  • Input Voltage: The supply voltage to which the variable transformer is connected.

  • Output Voltage: The range of voltage available at the output terminals.

  • Frequency: All units in this catalog operate in the range of 50 to 400 Hz.

  • Rated Current: Output current that can be drawn at any brush setting for a continuous duty.

  • Intermittent Operation: The current rating may be multiplied by the square root of the Duty Cycle Ratio, this being defined as the off-plus-on-time divided by on-time. The resulting up-rated current must be compared with the short-time overload current, the lower of the two figures being the maximum permissible current.

  • KVA Rating: the maximum output current at maximum output line voltage multiplied by that max voltage and divided by 1000 for single-phase. Divide by 577 for three-phase (1000/√3).

  • Line-Voltage and over-Voltage connection: With line-voltage connections, the supply is connected across the whole winding, and the maximum output equals the applied voltage.

  • In over-voltage connection, the supply is applied to a tapping provided instead of to the whole winding, giving e.g.: 0-280 Volt from a 220 Volt supply.

  • Ambient Temperature: Current ratings apply up to 45°C ambient. For ambient temperatures above 45° C, rated current should be reduced according to the figure below.

  • ANG Autotransformers – Temperature Curve.

  • Insulation: All ANG variable transformers are flash-tested at 2,5 KV. rms 50 Hz.

Voltage Regulator ambient temperature


Frame Sizes:

ANG variable autotransformers are made in seven basic series or frame size V1 – V3 – V5 – V10 – V20 – V40 – V70.

Electrical specifications are given in the detailed tabulations for the various models.

Optional features can be provided.

Single and three phase:

Single phase – suffix “V”

Three phase – suffix “T”

Uncovered models

All basic variable transformers are available in uncovered form.

These units are designed with the suffix: NA (ex V5 NA Single phase uncovered, T5 NA Three phase uncovered).

Covered models:

All single units and ganged assemblies are available in styled enclosure.

Suffix: NC (ex V 5 NC single phase covered).

Portable models:

V1 – V3 – V5 – V10 – V20 series can be supplied in portable cases with carrying handles, input lead, switch, output fuse.

A digital voltmeter LED (suffix PV) can be provided. The portable models are also available with volt-meter and ammeter (suffix PVA).

Output receptacles:

In the models covered and portable the output can be taken through:

socket type “schuko” (up to 10 A) suffix SCH

CEE socket 16-32-64 A suffix CES16, CES32, CES64 insulated terminals suffix ILT.


Motor Drive:

All open and covered voltage regulators are available with reversing motor drive for remote control and automatic applications.

Suffix: M (ex V 5 NA/M is a motor-drive single phase open construction-uncovered).

Ganged assemblies:

All voltage regulators are available assemblies of two, three, four, five, six units operating on one common shaft for parallel or series. The number following the suffix NA or NC indicated the number of ganged regulators (add SR for series connection).

Example: V 70 NA/6-M is a single phase uncovered motor-drive regulator with six units in parallel. V 70 NA/2SR-M two units series connection.

Optional features:

Non standard voltage or non standard current, limit switches, special shaft and special motors can be supplied to customer’s special requirements.