Document Overview:
This technical document provides detailed specifications, design parameters, and mounting options for Type 51 clutches manufactured by Stephenson Gobin Ltd., a British Engines Group Company. The clutches are intended for various industrial applications including military, medical, material handling, energy, security, leisure, processing, access control, industrial trucks, and machinery sectors.

1. Clutch Types and Field Mounting Options

• Field Mounting Types: F.M. (Flange Mounting), S.B. (Shaft Bracket), B.B. (Back Bracket)
• Clutch Types: Type 51 with various bore sizes and armature types
• Key Features: Keyways conforming to British Standard (B.S.) 4235, Circlip grooves to B.S. 3673, Insulation Class B for electrical components

2. Dimensional and Performance Specifications

The document contains comprehensive tables listing clutch sizes from 00 to 20, with corresponding mechanical and electrical parameters:

• Torque (TS): Ranges from 0.30 Nm (size 00) up to 240 Nm (size 20)
• Maximum Power (P20): Power ratings from 5 W to 65 W depending on size
• Dimensions: Detailed dimensions including diameters (A1, A2, A3), lengths (B, C1, C4, C5), bore sizes (E1, E2, E3, E4, E5, E6, E7, E8), and mounting hole specifications (U1, U2, U3, U4, U6, U7, W1, W2, S1, S3)
• Tolerances: Specified fits such as h7, k6, H7, and others for precise assembly
• Mounting Details: Hole sizes, slot dimensions, and thread sizes (e.g., M3, M4, M5, M6, M8) for secure installation

3. Design Variants and Optional Features

• Keyseat or Flat Options: Optional keyseat or flat surfaces on shafts for secure coupling
• Circlip Grooves: Available on request for additional retention
• Taperlock Bush: Supplied fitted on size 20 B.B. clutches for ease of mounting

4. Standards and Compliance

• Keyways and circlip grooves conform to British Standards B.S. 4235 and B.S. 3673 respectively
• Electrical insulation class B ensures reliable operation under specified thermal conditions

5. Application Sectors

The clutches are designed for use in diverse sectors including:

• Military and Medical Equipment
• Material Handling and Energy Systems
• Security and Access Control
• Leisure and Processing Machinery
• Industrial Trucks and General Machinery

6. Critical Parameters and Recommendations

• Ensure correct selection of clutch size based on required torque and power ratings
• Adhere to specified tolerances and mounting dimensions for optimal performance and longevity
• Use recommended keyseat or flat options and circlip grooves as per application needs
• Follow insulation class requirements to maintain electrical safety and durability

Summary:
This document serves as a comprehensive technical reference for selecting and installing Type 51 clutches with various field mounting options. It emphasizes adherence to British Standards, precise dimensional control, and offers optional features to customize clutches for specific industrial applications.