PRECILEC RE.0444N Guide for On site Maintenance and Replacement of DC Speed Generator

PRECILEC RE.0444N Guide for On site Maintenance and Replacement of DC Speed Generator

In industrial speed control and regulation systems, a DC tachometer generator is a feedback component that converts mechanical speed into an analog voltage signal. It is widely used in applications that require precise speed closed-loop control, such as elevators, steel mills, CNC machine tools, and generator excitation regulation. RE.0444N (model suffix N represents standard type) is a permanent magnet DC tachometer generator produced by a European manufacturer. With its maximum speed of 12000 rpm, maximum electromotive force of 600V, and multiple mechanical/electrical options, it has become an irreplaceable feedback component in many old equipment or imported production lines.

However, as the service life of the equipment increases, the original RE.0444N may face end-of-life, performance degradation, or accidental damage. How to accurately select substitutes, install and debug on site, and diagnose typical faults (such as excessive ripples, poor linearity, and temperature drift) has become an urgent need for maintenance engineers. This article is based on the original technical specification of RE.0444N, combined with the general maintenance experience of the speed generator, systematically sorting out the key parameters, installation dimensions, wiring polarity, performance verification methods, and replacement process of this model, to help engineers quickly restore the equipment speed feedback function.

Chapter 1 RE.0444N Core Parameters and Technical Characteristics

1.1 Basic Structure

RE.0444N is a two pole (2 poles) permanent magnet DC tachometer generator, which uses Alnico permanent magnet material for excitation and does not require an external excitation power supply. The number of armature slots is 19, the number of commutator segments is 57, the insulation level is Class B (IEC 34-1), and the maximum allowable winding temperature is 130 ℃. The protection level is IP44, and if a sealing cover is selected, it can be increased to IP55, suitable for general industrial dust and drip environments. The climate protection level complies with the Ca level (moisture and heat resistance) of IEC 68-1.

Key mechanical parameters:

Net weight: 1.8 kg (single commutator type), 2.1 kg (double commutator type)

Moment of inertia: 0.95 kg · cm ²

No load driving torque: 1.5 N · cm

Time constant: 2.5 ms (fast response)

1.2 Electrical performance indicators

Parameter symbol numerical description

Maximum speed n_max 12000 rpm, short-term allowable

Maximum electromotive force E-max 600 V output upper limit

Recommended load for high impedance input with load current of 5 mA

Calibration accuracy Δ E ± 1% E factory calibration deviation

Maximum linear error Δ E ≤ 0.15% E Optimal linearity

Overall ripple rate (peak to peak value) Δ E ≤ 0.5% E commutation ripple

Slot harmonic (Z · n) Δ E ≤ 0.3% E frequency is the number of slots multiplied by the rotational speed

Rotating harmonic (2p · n) Δ E ≤ 0.2% E frequency is 2 x number of poles x speed

Electromotive force temperature drift (uncompensated) 0.02%/℃ per degree change of 0.02%

Electromotive force temperature drift (compensation) 0.005%/℃ improved by compensating winding

Analysis: The low linear error (≤ 0.15%) and low ripple rate (≤ 0.5%) of RE.0444N make it suitable for high-precision speed control. When the temperature drift is not compensated, it changes by 0.2% every 10 ℃. For a wide temperature environment, a compensation type or an external temperature compensation circuit should be selected.

1.3 Optional Filter Parameters

If a built-in or external filter is used, its time constant is 0.47 ms, which can effectively weaken the commutation ripple, but it will introduce a small phase lag. A trade-off is needed in the fast response speed loop.

Chapter 2 Detailed Explanation of Installation Forms and Dimensions

RE.0444N offers two standard mechanical installation forms: flange installation (B5) and foot installation (B3), and supports multiple shaft diameters and bearing options.

2.1 B5 flange mounting

The flange is installed by fitting the front circular flange to the motor or machine end face and fixing it with bolts. Suitable for coaxial direct connection with the dragging motor.

Key installation dimensions (unit: mm):

Shaft diameter (D) 1 commutator A 2 commutator A 1 commutator B 2 commutator B 1 commutator C 2 commutator C

Ø7 mm 126 142 132 148 14.5 30.0

Ø11 mm 131 —— 137 —— 17.5 ——

Ø14 mm 128 —— 141 —— 21.5 ——

A: The length from the flange end face to the first commutator installation face

B: The length from the flange end face to the installation surface of the second commutator (if any)

C: The length of the commutator itself (axial direction)

Note: The dual commutator model (2 commutators) only offers Ø 7 mm shaft diameter, and the two commutators are arranged axially, increasing the total length.

2.2 B3 Base mounting

The foot installation is fixed on the substrate through four mounting holes at the bottom of the machine base, suitable for independent installation or connection through a coupling.

Typical appearance: The height from the surface of the foot to the axis meets IEC standards. Please refer to the original factory drawings for specific dimensions (detailed data is not provided in the PDF, but can be confirmed by measuring the actual object).