Bonfiglioli BTD/BCR Synchronous Servo Motor Selection and Interface Configuration Guide

BCR8: Shaft diameter D=42 mm, shaft length E=106 mm, flange stop A=230 mm, installation hole spacing B=265 mm.

Attention: The maximum allowable radial and axial forces corresponding to different sizes (see the "Max load on shaft" table in each chapter of the manual) must be checked during selection. Radial force (F_R) usually refers to the pressure generated by pulley or sprocket transmission, while axial force (F_A) refers to the thrust parallel to the motor shaft. Exceeding the allowable value will directly lead to a shortened bearing life or a risk of shaft breakage.

2. Installation and alignment requirements

The installation surface must be flat to ensure a tight fit between the flange and the equipment.

When connecting the coupling, it is necessary to strictly calibrate the coaxiality between the motor shaft and the load shaft to avoid generating additional radial stress. It is recommended to use a highly elastic coupling to absorb slight alignment errors.

Feedback system: parser and encoder options

The accuracy of feedback equipment directly affects the control accuracy and speed stability of the motor.

1. Standard configuration: Transformer (Resolver)

All BTD and BCR motors come standard with 2-pole rotary transformers. The main technical indicators are as follows:

Accuracy: The absolute accuracy can reach ± 4 '(arc minutes), and the repeatability accuracy is 1', which can meet the vast majority of industrial applications.

Environmental adaptability: The rotary transformer is a sturdy and durable magneto resistive sensor that can withstand temperatures ranging from -55 ° C to+155 ° C. It has strong resistance to vibration and pollution, making it very suitable for harsh industrial environments.

Interface: Connected through a 12 core signal connector, the driver interface is usually SUB-D9 or terminal connection (requires EMRES-03 interface module).

2. Optional configuration: Encoder

For applications that require higher accuracy, lower speed fluctuations, or absolute position memory, multiple incremental or absolute encoders can be selected:

SinCos incremental encoders (such as Heidenhain ERN series): provide high-resolution sine and cosine signals, and with the interpolation technology of the driver, can achieve extremely high positioning accuracy.

Absolute encoders (such as Heidenhain ECN/EQN series or Sick Stegmann Hiperface series): transmit absolute position data through EnDat or Hiperface protocols without the need for zeroing operations, suitable for multi axis linkage and complex contour machining.

Selection suggestion: If you need to memorize the position or perform high-precision contour processing after power failure, absolute encoders should be preferred.

Thermal protection and braking options

1. PTC thermistor protection

All motors come standard with PTC thermistors (compliant with DIN 44081) and are integrated into the signal connectors of the motor windings (pins 2 and 6). The driver monitors the changes in PTC resistance value to determine the winding temperature in real time. When the temperature reaches the protection threshold (usually 140 ° C), the driver should immediately cut off the output to protect the motor from overheating and burning out. It is strictly prohibited to operate the motor without PTC monitoring.

2. Maintain the holding brake

As an optional item, the rear of the motor can be integrated with an electromagnetic brake that is spring-loaded and electrically released. Its main purpose is:

When the drive is powered off or emergency stopped, hold the motor shaft tightly to prevent the load from falling due to gravity (such as a vertical axis).

When the motor is stationary for a long time, replacing the output torque of the driver can save energy and prevent the motor from overheating.

Selection precautions:

The brake adopts 24V DC power supply (tolerance+6%/-10%).

Installing the brake will increase the length and total weight of the motor. The specific increment can be found in the size chart (K value variation) of each machine base in the manual.

The brake torque in the data table (such as 2 Nm for BTD2 and 145 Nm for BCR8) is usually much smaller than the motor stalling torque and is only used for static holding and cannot be used for dynamic braking.

Electrical connection and cable selection

1. Power connector

Adopting a 4+4-core heavy-duty connector (compliant with Desina standards), it integrates motor power lines and brake power lines. The pin definitions are unified, and even if no brake is selected, the pin positions are still retained in the connector for easy wiring.

2. Signal connector

Using a 12 core connector for transmitting rotary transformer signals and PTC signals. If an absolute value encoder is selected, it will be replaced with a higher density connector (such as 17 cores) to accommodate the additional data cables required by EnDat or Hiperface protocols.

3. Selection Guide for Servo Cables

The manual provides detailed optional cables (orange power cable, green signal cable) and their models.

Power cable: Four wire diameters of 1.5 mm ², 2.5 mm ², 4.0 mm ², and 10.0 mm ² are provided according to the motor current. For example, a high-power motor with BCR 8 size requires the use of a 10.0 mm ² cable (model 42MBCx100).