TABLE OF CONTENTS In addition to transformer electrical characteristics, their thermal and sound level characteristics are very important. Thermal characteristics are determined by industry standards (UL/ANSI 1561-1987) and are generally only of concern to the electrical design professional. Sound levels, on the other hand, are of concern to everyone, especially the architect and occupants of the building. Electrical design professionals must be sensitive and aware of the sound levels of electrical equipment and their impact on the occupants of the building and exercise appropriate measures to mitigate their effects. These could include remotely locating the equipment, sound attenuation techniques, and/or structural isolation. To assist you in evaluating these considerations, Figure 3.36 shows the thermal characteristics of dry-type distribution transformers, and Tables 3.37 and 3.38, respectively, show the maximum average sound levels of drytype and liquid-filled transformers and typical ambient sound levels.
| Radio, Recording and TV Studios | 25-30 db |
| Theatres and Music Rooms | 30-35 |
| Hospitals, Auditoriums and Churches | 35-40 |
| Classrooms and Lecture Rooms | 35-40 |
| Apartments and Hotels | 35-45 |
| Private Offices and Conference Rooms | 40-45 |
| Stores | 45-55 |
| Residence (Radio, TV Off) and Small Offices | 53 |
| Medium Office (3 to 10 Desks) | 58 |
| Residence (Radio, TV On) | 60 |
| Large Store (5 or More Clerks) | 61 |
| Factory Office | 61 |
| Large Office | 64 |
| Average Factory | 70 |
| Average Street | 80 |
| kVA | Dry-Type | Liquid-Filled |
|---|---|---|
| Self-Cooled Rating (AA) | Forced-Air Cooling... |
