Bonfiglioli BXN/MXN Motor Installation and Brake Maintenance Complete Guide

Complete guide for installation and brake maintenance of Bonfiglioli BXN/MXN series motors

In industrial transmission systems, the motor is the core power source, and its installation quality and maintenance level directly determine the reliability of the entire production line. Bonfiglioli's BXN, BX, BE, BN and compact MXN, MX, ME, M series three-phase asynchronous motors are widely used in various harsh working conditions due to their high energy efficiency (IE2/IE3) and rich braking options (FD DC braking, FA AC braking). However, even the highest quality motors can result in unplanned shutdowns or even safety accidents if there are omissions in installation wiring, brake adjustments, or regular maintenance.

This article will be based on Bonfiglioli's official "Installation, Operation, and Maintenance Manual" to provide on-site engineers with a full process technical guide from receiving acceptance to daily maintenance. The focus will be on analyzing key operations such as air gap adjustment, rectifier wiring, and insulation testing unique to brake motors to ensure safe and efficient operation of the equipment throughout its lifecycle.

Safety first: Essential checks before installation

Before coming into contact with any motor, it is necessary to confirm that the operator is qualified and familiar with safety regulations. The manual clearly states that the motor has live or rotating parts during operation, and removing the protective cover, improper use, or inadequate maintenance may result in serious personal injury.

Identification of nameplate: Each motor has a nameplate, which includes the serial number and production year. When the serial number is 17 digits, the year is in the 3rd to 4th digits; At position 13, it is in positions 5-6. Before starting any installation, it is essential to verify whether the voltage, frequency, power, and braking parameters on the nameplate match the on-site power supply.

Transportation and storage: The motor is usually fixed on a wooden pallet and can be transported by forklift. For motors with base numbers BXN100/MXN30 and above, eyebolts are provided, but they are only suitable for lifting the motor itself and are strictly prohibited from being used to lift the entire gear motor or assembly. When stored for more than 60 days, rust inhibitor (such as Mobilarma 248) should be applied to the flange and shaft extension surfaces; If it exceeds 6 months, the rotor should be rotated once a month to prevent the bearing grease from solidifying.

Mechanical installation: Details determine lifespan

2.1 Axial extension treatment and corrosion prevention

When the new motor leaves the factory, the shaft extension is coated with a rust proof protective layer. Before installation, it needs to be cleaned with a suitable solvent, but do not let the solvent come into contact with the oil seal lip, otherwise it will cause the sealing ring to swell and fail. After cleaning, apply anti seize agent (such as Loctite 767) on the shaft to effectively prevent micro corrosion of the shaft and its mating parts, and also provide convenience for future disassembly. The manual recommends removing the motor, cleaning the shaft extension, and reapplying anti seize compound every 6-12 months.

2.2 Installation Space and Heat Dissipation

The motor adopts IC411 self cooling method (with built-in fan), and it is necessary to ensure that there is sufficient distance between the fan cover and the surrounding walls or obstacles to ensure free circulation of cooling air. When installing outdoors, it is necessary to install a sunshade to prevent direct sunlight and rainwater from entering. For brake motors with manual release levers, the release lever should be unscrewed and properly stored after installation to prevent accidental misoperation that may cause the brake to release.

2.3 Insulation resistance test

After the first start-up or long-term parking, a 500V DC megohmmeter must be used to measure the insulation resistance of the winding to ground. The insulation value of the new winding at 25 ℃ should be greater than 10M Ω. If it is lower than this value, it indicates that the winding is damp and needs to be dried in an oven, otherwise forced power transmission may cause inter turn short circuits.

Electrical wiring: the core points of brake wiring

Bonfiglioli motors offer multiple wiring schemes, especially for motors with DC brakes (FD type), the correctness of wiring directly affects the braking response time and safety.

3.1 Standard Single Speed Motor Wiring

The terminal box is usually pre connected with a rectifier (for FD braking). Connect the main circuit according to the Δ/Y connection indicated on the nameplate (230/400V or 400/690V). The grounding terminal must be reliably grounded.

3.2 Four typical control schemes for FD brakes

According to whether independent power supply or rapid braking is required, the manual provides four types of wiring diagrams (A~D):

Option A (standard): The brake coil is powered by the motor terminal, and the braking action is delayed when the AC side is disconnected. It is suitable for soft start/stop situations.