Overview
ROLIVAM Tachogenerators are precision devices designed for use in servo-drive systems. They are manufactured by a leading producer of A.C. and D.C. servomotors and are engineered to perform tasks such as stopping, positioning, accelerating, or changing direction with minimal cogging and fluctuations under 1.5% (pp).

Design and Configuration
The tachogenerators feature an electro-mechanical configuration with winding on two parallel branches and four brushes (two on each line). They include a copper-silver alloy commutator with numerous segments, rare-earth permanent magnets, and are characterized by very low inertia and high manufacturing quality. This design ensures reliable signal transmission and rapid response in applications requiring quick reversals.

Technical Specifications

• Voltage Constant: ±5%
• Ripple at 1000 rpm: Less than 1.2% (pp)
• Linearity at 6000 rpm: <0.1%
• Reversing Error: <0.12%
• Temperature Coefficient: 0.02°C/%
• Rotor Inertia: 0.024 kg m² x 10^-3
• Resistance: 72-380 Ω depending on model
• Inductance: 16-190 mH depending on model
• Current: 5-3 mA depending on model
• Maximum Current: 20-10 mA depending on model
• Maximum Speed: 8,000-9,000 rpm
• Brushes Life Expectancy: 1.1x10⁹ to 3.24x10⁹ revolutions
• Number of Poles: 4

Models
The document lists several models including D-23 A, D-25 A, D-26, D-40, D-41 A, and D-41 B, each with specific mass and technical parameters.

Conclusion
ROLIVAM Tachogenerators are highly reliable components suitable for precision applications in servo-drive systems, offering excellent performance with minimal error and high durability.