AUTO-TRANSFORMER

Typical Number in Hospital: 10

Cost Bands: 1,2

References:

The mains supply voltage available at a wall socket in a hospital may not be appropriate for all equipment. This is most commonly encountered where American equipment requiring 110 V is to be used on the 250 V supply found in European hospitals. The solution to the problem is to use an auto-transformer which is a single coiled winding on a laminated iron core on which there are various tapping points to produce different voltages. The use of single winding means that the bulk of the device is much smaller than for a conventional double-wound transformer. Some auto- transformers can provide a variable output (a Variac) in which the number of turns of the coil presented in the output circuit can be varied by adjusting a control knob. Auto-transformers are most commonly encountered in the pathology departments where the equipment is drawn from a wide market. Often the suppliers of foreign equipment will incorporate an auto-transformer inside the equipment so that no additional device is required.