How to deal with and maintain the magnetic suspension blower after it fails?

The core of fault maintenance of magnetic suspension blower is to safely cut off the power, check the fault code, and conduct classification inspection according to "Mechanical → Electrical → Control → System". The core components (magnetic bearing/inverter/motor) must be handled professionally, and blind disassembly is strictly prohibited. Here is a set of troubleshooting and maintenance procedures that can be directly landed.

I. Safe operation before maintenance (absolute bottom line)

Completely cut off power and check electricity.

Cut off the main power supply and control power supply, hang the sign of "No Closing", and wait for **≥5 minutes to discharge the capacitor.

Do not touch the electrical components until you confirm that there is no electricity with the test pen/multimeter; High-voltage models must be operated by certified electricians.

Rotor shaft drop confirmation

After the magnetic suspension fan is powered off, the rotor slowly falls to the mechanical protection bearing by the standby power supply. Manual turning or disassembly is strictly prohibited before the completion of shaft dropping is confirmed.

Manual turning must use special tools, and it is forbidden to directly grasp the impeller.

Tools and data take precedence.

Firstly, the fault code and real-time parameters (vibration/temperature/current/speed) are derived from HMI/controller, and the location is controlled according to the manufacturer's manual, so as not to disassemble the machine blindly.

Key measurement: the suspension gap is calibrated by the manufacturer's special displacement calibrator; 1000V megohmmeter for motor insulation; Spectrometer for vibration.

Second, the fault classification investigation and maintenance (from high to low probability)

(1) Mechanical failure (vibration/abnormal sound/insufficient air volume)

1. Excessive vibration/abnormal noise (most common)

Reason:

The installation is not horizontal and the anchor bolts are loose;

Dust accumulation/wear of impeller and dynamic balance damage;

Friction between the impeller and the shell protects the bearing from dry grinding;

Hard transmission of pipeline stress and instability of magnetic bearing.

Maintenance steps:

Stop the machine to check the anchor bolts and levelness, and re-calibrate and tighten them;

Open the casing, clean up the dust accumulated on the impeller, and return to the factory for dynamic balance if it is seriously worn;

Check the clearance between impeller and casing (usually 0.3–0.8 mm) and adjust or repair it;

Check whether the protective bearing is worn or not, and replace it if necessary;

Optimize pipeline support and eliminate hard force;

If the magnetic bearing is abnormal, it is necessary to check the parameters of the sensor and controller to eliminate the magnetic field interference.

2. Insufficient air volume/wind pressure

Reason:

The air inlet filter is blocked;

Impeller wear and excessive clearance;

The rotation speed does not reach the set value;

Pipeline leakage and excessive resistance.

Maintenance steps:

Clean/replace the filter and purge it regularly;

Check the impeller wear and seal clearance, and repair or replace it;

Confirm the frequency and speed sensor signals output by the frequency converter;

Leak detection and plugging, optimizing pipeline layout and reducing resistance.

3. Surge (flow/pressure/current oscillation, low "hoo-hoo" sound)

Causes: the operating point falls into the surge zone, the anti-surge valve is not opened, and the downstream resistance is too large.

Maintenance steps:

Variable frequency speed/large guide vane, exit the surge zone;

Check whether the anti-surge valve is automatically opened and manually forced to open and empty;

Reduce system resistance (cleaning filters and optimizing pipelines).

(2) Electrical and drive failures (unable to start/overload/overheating)

1. The motor cannot be started/frequently trips.

Reason:

Lack of phase of power supply, voltage instability and harmonic interference;

Inverter overcurrent/overload, IGBT damage;

Motor insulation drops and winding is short-circuited;

Protection device (overload/overheating) triggered.

Maintenance steps:

Measure three-phase voltage and current, and check the lack of phase/voltage fluctuation;

Reset inverter protection and check fault codes (such as OC overcurrent and OL overload);

Use a 1000V megohmmeter to measure the insulation of the motor (not less than 5m Ω is qualified), and the three-phase resistance deviation is not more than 5%;

Clean the heat dissipation of frequency converter and check the fan; IGBT damage requires professional replacement/factory repair.

2. The motor/bearing temperature is too high.

Reason:

Failure of cooling system (water cooling/air cooling) and insufficient flow;

The cooling air duct is blocked and the ambient temperature is too high;

Excessive load and abnormal loss of magnetic bearing.

Maintenance steps:

Check water cooling: water pressure/flow rate, heat exchanger, whether there is scaling leakage;

Check the air cooling: fans, air ducts and filter screens, and clean up the accumulated dust;

Reduce the load and check the current and temperature parameters of the magnetic bearing;

The temperature of the control cabinet shall be controlled at < 40℃ and the humidity at < 50%.

(3) Magnetic Bearing and Control Fault (core, must be professional)

1. Magnetic bearing failure/suspension instability (BEARING_LOSS)

Reason:

Displacement/current sensor failure, loose wiring;

Controller parameter drift and strong magnetic field interference;

The bearing coil is damaged and the permanent magnet demagnetizes.

Maintenance steps:

Check the sensor wiring, shield grounding, and eliminate interference;

Calibrate the suspension gap and check the sensor signal with special tools;

Restart the controller and restore the factory parameters;

The damaged coil/permanent magnet must be returned to the factory or repaired by the manufacturer, and it is forbidden to disassemble it by itself.

2. Abnormal control system (crash/communication interruption/false alarm)

Reason:

24V power supply ripple is too large, switching power supply failure;

The communication line is unshielded and poorly grounded;

Program BUG and low firmware version.

Maintenance steps:

Replace low ripple (< 1%) DC24V power supply;

The communication line is replaced by shielded wire and single-ended grounded;

Upgrade the firmware of the controller and do 24-hour aging test;

Check the UPS battery, replace it every year and do a power-off test.

Third, debugging and power transmission process after maintenance

Static inspection

Confirm that all components are installed in place, correctly wired and free of foreign objects;

Turn the car manually (after falling off the shaft), and the rotation will be smooth without sticking.

Step by step power transmission

Send control power first, and check that HMI, sensor and controller have no alarm;

Then send the main power, run at 50% speed for 15 minutes, and monitor the vibration, temperature and current.

dynamic debugging

Gradually load to the rated working condition, and calibrate the speed, air volume and wind pressure;

Optimize anti-surge and PID parameters to ensure stable operation.

Record archiving

Record the cause of failure, maintenance contents and debugging parameters, and establish equipment files.

Four, the key maintenance taboo and outsourcing principle

Self-disassembly is strictly prohibited: magnetic bearings, high-speed motors and inverter power modules (IGBT) are precision parts and must be repaired by authorized engineers of the manufacturer.

It is forbidden to measure the suspension gap with a common feeler gauge: a special displacement calibrator must be used by the manufacturer to avoid damaging the sensor.

Fault code priority: not judged by experience, but based on controller fault code and parameters.

Core fault outsourcing: magnetic bearing failure, motor winding short circuit, inverter motherboard/IGBT damage, directly contact the manufacturer for after-sales.

Five, quick troubleshooting quick look-up table

form

Fast processing of priority troubleshooting items for fault phenomena

Unable to start and report the overcurrent power supply, frequency converter and motor insulation voltage check → reset → insulation measurement.

Fasten the foundation, impeller and protective bearing with large vibration and abnormal sound → clean the ash → check the gap.

Cooling system with high temperature, load clearing and heat dissipation → load reduction

Suspension instability sensor, magnetic field interference check wiring → parameter calibration.

Insufficient air flow: filter, impeller and speed change filter element → check the gap → calibrate the speed.

Surge anti-surge valve, system resistance valve opening → resistance removal → speed increase.

Six, daily maintenance and prevention (reduce failure)

Weekly: Clean the filter, check the cooling system and check the vibration/temperature trend.

Monthly: calibrate sensors, check wiring and grounding, and test UPS.

Every quarter: check the dynamic balance, clean the heat exchanger and upgrade the firmware of the controller.

Every year: overhaul the performance of magnetic bearing, motor insulation and frequency converter, and return to the factory for maintenance if necessary.