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 three main categories below:


  • Efficient – transforms power more efficiently than rheostats;
  • Durable – because it runs cool (40/50°C max);
  • Overload-able 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.

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

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 brushgear.

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.

The wound core and brushgear 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.

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

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


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:
a) socket type “schuko” (up to 10 A) suffix SCH
b) 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.

All ANG variable autotransformers; both single and ganged units, can be furnished with motor drive (denoted by the suffix “M”).
Motor driven models permit remote control of large amounts of power. A ANG motor driven variable autotransformer can be installed in any out-of the way space and the control station placed where desired, they have the same electrical ratings as their corresponding manually-operated models. The motor-drive is a compact integral unit mounted on top of the assembly.
In the standard arrangements the voltage regulator is driven by a geared A.C. continuously-rated reversing motor 220V or D.C. motor 24V. Speed (from zero to maximum output voltage) 4 sec. – 8 sec. – 16 sec. – 32 sec. – 64 sec. (Other speeds are also available on request).

Emergency hand control:
Slipping clutches are available on all models as an optional extra.

Limit switches:
Limit micro-switches control at the lower and upper limits to prevent over-run are always fitted as standard, and are fully adjustable.
Additional limit switches may be added for operation and control of auxiliary circuits.

This option provides control voltage by an electronic board having an input signal from a PLC 0-10V Vdc and supplying an output signal (go-stop) to a gear motor of variac. As input signal change from zero up to 10V output voltage, i.e. voltage supplied by variac changes from zero to maximum rated voltage. Output voltage is directly proportional to output signal, i.e. if signal is 5V output voltage will be just half of maximum voltage. Output voltage can be controlled also by a potentiometer (remote control).

Rating and distinctive features:

  • Suitable for motor 24 Vdc;
  • Input control voltage 0-10Vd.c.;
  • Supply voltage 220 Va.c.;
  • Regulation directly proportional;
  • Output voltage stability ±1,5% (Whether for load change 0-100% or supply mains change ±10%).


  • Electronic printed board with supply mains 220/24V d.c. input/output terminal board. All components secured to aluminum plate of variac.

All covered and portable models are available with voltmeter, ammeter and wattmeter. The suffix for meter identification are: V=Voltmeter, A=Ammeter, W=Wattmeter.

In addition to the complete line of standard products illustrated and described, “A.N.G. Converters” manufactures a variety of special variable autotransformers. Typical example is the variable autotransformer with a separate transformer with primary winding which is electrically isolated from the secondary or output winding. There is no common connection between the input and output of the transformer.