Bonfiglioli BN-BE-BX Series Motor Selection Guide

Bonfiglioli BN-BE-BX Series Three phase Asynchronous Motor: Selection, Configuration, and Braking System

In the field of industrial transmission, the selection of three-phase asynchronous motors as the core power execution components directly determines the efficiency and reliability of the entire production line. Bonfiglioli's BN, BE, BX series motors cover all efficiency levels from IE1 to IE4, providing a wide range of power options for general industrial applications such as pumps, fans, compressors, and material conveying. However, faced with a multitude of machine base numbers, pole numbers, voltage combinations, and braking options, engineers often need to make a large number of detailed decisions during the selection stage. This article will be based on the technical documents of the BN-BE-BX-BY series, and provide you with a complete selection approach from understanding energy efficiency standards to implementing specific models.

Evolution of Energy Efficiency Grades and Interpretation of Standards

To understand the essential differences between the BN, BE, and BX series, it is first necessary to clarify the evolution of global motor energy efficiency standards.

1. Definition from IE1 to IE4

The International Electrotechnical Commission (IEC) defines the International Energy Efficiency (IE) rating for motors through the standard IEC 60034-30-1:2014. The manual clearly lists the level codes on pages 5-6:

IE1 (Standard Efficiency): Standard Energy Efficiency, corresponding to the BN series

IE2 (High Efficiency): High efficiency, corresponding to the BE series (and compact ME series)

IE3 (Premium Efficiency): Ultra high energy efficiency, corresponding to BX series (as well as compact MX series)

IE4 (Super Premium Efficiency): Ultra premium energy efficiency, covering some specific models

This grading system has been adopted by the EU ERP Directive (2009/125/EC) and EU Regulation 2019/1781. Starting from July 2023, the European market has mandated that motors within a specific power range must have an energy efficiency rating not lower than IE3. Therefore, when choosing motors, if the target market is Europe, choosing BX (IE3) or higher directly is a wise move to avoid compliance risks.

2. Special considerations for frequency converter power supply

For variable frequency drive (VSD) applications, traditional IE rating standards are not fully applicable. On page 6 of the manual, it is stated that IEC TS 60034-30-2:2016 specifically defines the energy efficiency level (IE code) for variable frequency motors. In addition, the IEC 61800-9 standard introduces the Extended Product Approach to evaluate the energy efficiency (IES level) of the entire system consisting of a frequency converter, motor, and load. This means that if the motor needs to operate in variable frequency mode for a long time, in addition to focusing on the efficiency of the motor itself, it is also necessary to comprehensively consider the loss matching of the driver.

Decoding Motor Naming Rules: Understanding Configuration from Model

Bonfiglioli's motor models follow a rigorous coding logic (pages 9-11 of the manual). Understanding this encoding is the first step in precise selection.

Taking model BX 132SB 4 230/400-50 IP55 CLF B5 W FD 7.5 R AA SB as an example:

Series code: BX represents IE3 efficiency level; BE is IE2; BN is IE1.

Machine base number and iron core length: 132SB represents a machine base height of 132mm, and SB is the code for iron core length (different lengths correspond to different powers). The correlation table (F64) on page 54 of the manual lists the correspondence between the machine base and power, for example, the rated power of BX 132SB 4 at 50Hz is 5.5kW.

Pole number: 4 represents a 4-pole motor (synchronous speed of approximately 1500rpm @ 50Hz). The BN/BE/BX series covers 2, 4, and 6 poles (some have 8 poles), and the different number of poles determines the speed torque characteristics of the motor.

Voltage and Frequency: 230/400-50 represents a voltage of 230V △/400VY and a frequency of 50Hz. Pages 20-21 of the manual provide detailed voltage combinations for different certification versions, such as CUS (North American Certification) version which is typically 265/460-60Hz.

Protection level and insulation level: IP55 is standard protection, CLF is F-level insulation (temperature rise limit of 105K). Optional CLH (H-class insulation) for higher temperature environments.

Installation method: B5 is flange installation (with flange); B3 is for horizontal foot installation; B14 is for small flange installation. On page 15 of the manual, it is stated that B3 can be combined with B5 or B14 to form B35 or B34.

Brake information: W represents the standard position of the junction box; FD stands for DC spring brake; 7.5 is the braking torque (Nm); R is the manual release lever (automatic reset); AA is the release lever orientation; SB is a rectifier type (overexcitation type).

Selection and Performance Parameters of FD Brake

The selection of brake motor is crucial for situations that require quick stopping or safe maintenance, such as lifting and hoisting equipment.

1. Working principle of FD brake

On page 32 of the manual, it is stated that the FD brake is spring applied and belongs to the fail safe type. When the coil is de energized, the pressure spring pushes the armature plate towards the brake disc, generating frictional torque to achieve braking; When the coil is energized, the electromagnetic force overcomes the spring force to release the brake disc. This design ensures that the brake can automatically engage in emergency situations such as power outages, ensuring safety.

2. Braking torque and heat capacity

Table F34 on page 36 of the manual lists the detailed parameters of different models of FD brakes. When selecting, special attention should be paid to:

Braking torque (Mb): For example, the torque of FD08 is 170-250Nm (adjustable by the number of springs). When selecting, it is necessary to ensure that Mb is at least twice the rated torque of the motor.

Maximum braking power (Wmax): represents the maximum energy (J) that a single braking can withstand. For example, at 100 cycles per hour, the Wmax of FD05 is 500J. If it frequently starts and stops and has a large load inertia, it is necessary to calculate whether the energy of each braking exceeds this limit.

Response time (t ₁, t ₂): Pages 35-37 of the manual compare the effects of different rectifiers (NB/SB/NBR/SBR) on response time. The SBR rectifier achieves rapid demagnetization through electronic switches, and the braking response time (t ₂ c) is significantly shorter than the standard AC power outage (t ₂).

3. Rectifiers and power supply configuration

On page 35 of the manual, four types of rectifiers are distinguished:

NB: Standard half wave rectification, economical type.

SB: Overexcitation rectification - provides high voltage rapid release at the moment of start-up, and then switches to holding voltage, suitable for high-speed response requirements.

NBR/SBR: Equipped with Quick de energizing function and independent braking power supply (SA or SD option) to achieve the fastest braking.

Engineering Tip: If the brake action frequency is extremely high (such as Z0 value approaching the limit in the table), SB or SBR rectifier must be selected, and CF capacitor filter option must be considered to suppress electromagnetic interference (meet EN 61000-6-3).

Hidden details of installation methods and mechanical interfaces

1. Special purpose of B5R "recessed flange"

On page 16 of the manual, a special flange execution method called B5R is mentioned. Its characteristics are short shaft expansion and contraction, and inward contraction of flange stop. This design is mainly used to match Bonfiglioli's own gearbox input flange, in order to achieve a more compact motor gearbox direct connection. The manual clearly warns that the combination of B5R and gearbox must be checked for the maximum input power allowed by the gearbox, as exceeding it may damage the gearbox.

2. Vertical installation (VM option) and rain cover (RC option)

Pages 15 and 52 of the manual emphasize:

For motors with base numbers BX ≥ 200K or BY ≥ 280K, if vertical installation (axis facing downwards) is used, the VM option must be specified because the bearing lubrication and drainage structure of standard horizontally installed motors is not suitable for vertical working conditions.

If installed vertically with the shaft facing downwards, it is recommended to choose an RC Rain Canopy to prevent condensation or splashing water from flowing into the internal bearings of the motor along the shaft.

3. Junction box and cable entry

Table F11 on page 18 of the manual provides a detailed list of cable entry specifications for junction boxes with different machine base numbers. For example, BX 160 (machine base 160) is equipped with 2 M40x1.5 and 2 M20x1.5 threaded holes, with a maximum allowable cable diameter of 28mm and 13mm, respectively. During the project design phase, if large section cables or servo cables with thick shielding layers are used, this size limit must be reviewed, otherwise an additional IC option (additional cable entry) needs to be selected.

Special considerations for inverter duty

The 30th page of the manual specifically discusses the precautions for inverter power supply.

1. Insulation system withstand voltage

The standard BX/BE motor adopts F-class insulation, but for the high-frequency pulse voltage (dV/dt) output by the frequency converter, its insulation system has a withstand voltage capability of 1600V peak to peak, and no additional output filter is required when the rising edge time t_r>0.1 μ s. This is Bonfiglioli's standard design guarantee, but if long cables (>50m) are used or the supply voltage is higher than 500V, it is recommended to contact the technical team to evaluate whether a sine wave filter needs to be installed.

2. Speed range and constant power range

When variable frequency speed regulation is used, the motor is in the constant torque range below the fundamental frequency (50Hz); Above the fundamental frequency is the constant power range (torque according to)

one/f The 1/f ratio decreases. On page 30 of the manual, the mechanical limit speed for each machine base is provided: for example, BX 132 allows a maximum of 4500 min ⁻¹, while BX 280K only allows 2000 min ⁻¹. If high-speed operation is required, the dynamic balance level must be checked, and if necessary, the RV (Balance Level B) option can be selected to reduce vibration.

3. Independent forced air cooling (U1/U2)

When the motor operates in the low-frequency range below 30Hz for a long time, the cooling effect of the built-in fan (IC411) drops sharply. At this point, it is necessary to select a forced air cooling system with independent power supply (U1 or U2 options). On page 47 of the manual, it is stated that U1 separates the fan junction box from the motor main junction box, while U2 introduces the fan power cord into the main junction box. For motors with brakes, after selecting U1, the default orientation AA of the brake release lever will not be available (this limitation is clearly stated on page 48 of the manual).

Quick Search for Global Market Certification Options

The BN-BE-BX series covers compliance certifications for major global markets (pages 22-27 of the manual), which is of great significance for export equipment manufacturers in terms of selection:

CUS (North America): UL/CSA certification, applicable to the United States and Canada. Please note that certain specifications of BX 100 are only available in the US market and are not applicable to Canada (page 24 of the manual).

CCC (China): Compulsory certification in China, applicable to specific power ranges of BN/M series.

CEL (China Energy Efficiency Label): For BX motors with a power output of ≥ 0.75kW, they must comply with the GB18613-2012 standard.

BIS (India): Certified by the Bureau of Indian Standards, covering BE/BX series ≤ 7.5kW.

EECA (Australia/New Zealand): Registration is required in the Energyrating database.

When selecting, the corresponding certification code must be clearly specified in the model based on the final export destination of the equipment.

Selection and Avoidance Guide

Neglecting the engineering margin of "locked rotor current and starting torque":

The BX-IE3 60Hz data sheet on page 62 of the manual shows the locked rotor current of BX90S 4P（Is/In）8.2, starting torque（Ms/Mn）For 4.1. If the capacity of the power transformer is insufficient (with a large voltage drop) or the static friction coefficient of the load is high, it may lead to startup failure. When selecting, it is necessary to verify the wiring capacity and rated current of the contactor.

Brake selection only depends on torque:

As mentioned earlier, braking power (Wmax) and response time (t ₂) are equally lethal. If the distance of the crane hook slip exceeds the standard, it is often not due to insufficient braking torque, but due to improper selection of rectifiers causing delayed braking response. At this point, an SBR rectifier must be selected and equipped with an independent DC power supply (SD option).

Misunderstanding the power mapping between "S1 working system" and "S3 working system":

The power amplification factors for S2 (short-term operation) and S3 (intermittent periodic operation) are provided on page 28 of the manual（fm）. If the equipment is actually operated under S3-40% intermittent working mode, but selected according to S1 continuous working mode, it will result in overly conservative motor selection and cost waste. Should utilize S3

fm=one point one five

f m=Reasonable selection of amplification factor of 1.15.

Vertical installation without considering bearing lubrication:

When installed vertically, the lubricating oil of standard bearings may not be effectively distributed. In the bearing table on page 19 of the manual, some large machine bases (such as BX 200K and above) have been marked with "Reguassable bearings with M6x1 Greasing Device", which need to be included in the regular grease injection maintenance plan after selection.