Power Newsletter March 2018


Variacs are the most popular variable auto transformers (also known as adjustable voltage transformers) on the market because they are cheaper, lighter, and smaller than dual-winding transformers. They also have a staggering number of applications.

MasTec Ltd has a full range of Variac Auto transformers. We represent leading suppliers like Belotti of Italy and Powertech

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


EFFICIENT - transforms power more efficiently than rheostats
DURABLE - because it runs cool (40/50° C max)
OVERLOAD-ABLE withstands 1000% overloads short term Power Products


- Regulate voltage (over and under-voltage testing of electrical and electronic equipments).
- Speed control
- Lighting control in theatres, 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 stabilisers)

Powertech Variable Laboratory Autotransformer is one of the most useful and efficient devices ever invented for the control of AC votage and of voltage-dependent parameters such as current, power, temperature, light intensity, motor speed etc. It enables the AC input to a mains powered appliance to be easily varied from 0 to full line voltage (or greater)

View our variacs range here






Variable Laboratory Autotransformer/Variac

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