Specifications:
The document provides detailed specifications for the BTO3 series of three-phase, four-pole alternators. It includes power ratings at different frequencies (50Hz and 60Hz) and voltages (230/400V and 277/480V). The alternators are designed for various applications with different pickup capacities and efficiencies.

Electrical Data:
Typical electrical data is provided, including synchronous, transient, and subtransient reactance values, as well as time constants for different operational conditions. The document also specifies the stator winding resistance and short-circuit ratio.

Mechanical and Thermal Protection:
The alternators come with various mechanical protection options (IP21, IP23, IP45, IP55) and thermal protection devices such as PTC and bimetal devices. The document outlines the standard and optional features available for these protections.

Dimensions and Weight:
Overall dimensions and weight for different models (BTO3-1S/4, BTO3-2S/4, etc.) are provided, along with the center of gravity for each model. The document includes detailed measurements for flanges and coupling discs.

Spare Parts List:
A comprehensive list of spare parts is included, detailing components such as bearings, terminal boards, protection screens, and various mechanical parts. Each part is listed with its code and description for easy identification.

Quality and Certification:
The document mentions that the company operates under a quality system certified by DNV according to ISO 9001 standards.