ABB XAC25762 - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

This document describes the Operation Manual for the ABB Turbo Systems Switzerland Ltd A255-L32 turbocharger, model XAC25762.

Function Description:

The turbocharger is a turbomachine designed for charging internal combustion engines, specifically 2-stroke engines that can operate with liquid and gaseous fuels. It consists of a turbine and a compressor, both installed on a common shaft, forming the rotor. Exhaust gases from the engine flow through the gas inlet casing and nozzle ring onto the turbine wheel, which uses the energy to drive the rotor and compressor wheel. The compressor wheel then draws in fresh air, compresses it, and delivers it to the engine cylinders. The air passes through a filter silencer to the compressor wheel, then through a diffuser, and exits the turbocharger via the compressor casing. An optional air outlet silencer can be installed to reduce noise. The rotor operates on two radial plain bearings located in the bearing casing between the compressor and turbine, with an axial thrust bearing at the compressor end. These plain bearings are supplied by the engine's lubricating oil circuit. The bearing casing integrates an oil tank that provides oil to the rotor bearings until standstill in case of an emergency engine stop due to lubrication system malfunction. The turbocharger is designed for clockwise rotation when viewed from the turbine end.

Important Technical Specifications:

The specific operating limits for the XAC25762 turbocharger are detailed on its rating plate.

Speed Limits:
- Speed limit in test rig operation only (nMmax): 472 1/s
- Speed limit during operation (nBmax): 454 1/s
Gas Inlet Temperature Limits:
- Gas inlet temperature limit in test rig operation only (tMmax): 550 °C
- Gas inlet temperature limit during operation (tBmax): 520 °C
Weight: The total weight of the complete turbocharger unit is 1500 kg.
Oil Supply: Lubricating oil filtering requires a filter mesh width of ≤ 0.050 mm.
Oil Pressure (before turbocharger):
- Admissible for normal operation (oil temp 30-65°C): 0.8-2.5 bar
- Admissible for normal operation (oil temp 65-80°C): 1.0-2.0 bar
- Admissible during engine warm-up (oil temp 30-65°C): 0.8-4.0 bar
- Admissible during engine warm-up (oil temp 65-80°C): 1.0-4.0 bar
- Temporarily admissible (< 1h) (oil temp 30-65°C): 0.6-0.8 bar
- Temporarily admissible (< 1h) (oil temp 65-85°C): 0.8-1.0 bar
- Not admissible (emergency stop) (oil temp 30-65°C): < 0.6 bar
- Not admissible (emergency stop) (oil temp 65-85°C): < 0.8 bar
- Admissible during pre-lubrication and post-lubrication (engine stopped): 0.2-0.6 bar
Oil Temperature (at inlet):
- Admissible: 30-80 °C
- Temporarily admissible (< 1h) (alarm): > 80 °C
- Not admissible (stop engine): > 85 °C
Oil Temperature (at outlet):
- Admissible (inlet 45°C): ≤ 110 °C
- Admissible (inlet 80°C): ≤ 125 °C
- Temporarily admissible (alarm) (inlet 45°C): > 110 °C
- Temporarily admissible (alarm) (inlet 80°C): > 125 °C
- Not admissible (stop engine) (inlet 45°C): > 120 °C
- Not admissible (stop engine) (inlet 80°C): > 135 °C
Admissible Air Inlet Temperature: -40°C to +45°C.
Speed Measurement System: The speed sensor (86505) for the A255-L model has a tightening torque of 150 Nm (M18x1.5).
Axial Clearance A (before/after assembly): For A255-L, the axial clearance is 0.31-0.55 mm.
Dry Cleaning Granulate: Average grain size 1.2-2.0 mm, specific weight not exceeding 1.2 kg/dm³. For A255-L, the quantity of water per cleaning process is 1.5 dm³.
Tightening Torques (foot screws): For A255-L (M27), torque-controlled tightening is 830 Nm, and angle-controlled tightening is 220 Nm pre-tightening torque with a 30 DEG tightening angle (3.1 DEG for every 10 mm additional screw length).
Tightening Torques (filter silencer screws): M10: 30 Nm, M8: 25 Nm.
Tightening Torques (nozzle ring screws 56014): For A255-L (M10), 35 Nm.
Tightening Torques (gas inlet casing screws 51087): For A255-L (M16), 30 Nm pre-tightening / 140 Nm tightening torque.
Tightening Torques (diffuser screws 77015): For A255-L (M5), 6 Nm.
Tightening Torques (wall insert screws 72002): For A255-L (M16), 60 Nm.
Tightening Torques (wall insert screws 72004): For A255-L (M16), 265 Nm.
Tightening Torques (filter silencer nuts 72004): For A255-L (M16), 265 Nm.
Tightening Torques (cover ring screws 57005): For A255-L (M8), 20 Nm.
Tightening Torques (rotor locking screws): For A255-L, B1 (M5) 6 Nm, B2 (M12) 75 Nm, B3 (M8) 25 Nm.

Usage Features:

Intended Use: Designed for 2-stroke internal combustion engines, operating with liquid and gaseous fuels.
Safety: Operation must be within specified limits, and only by trained personnel. Compliance with the Operation Manual and engine builder's instructions is mandatory.
CE Conformity: ABB turbochargers comply with Machinery Directive 2006/42/EC.
Deflagration on Gas Engines: ABB turbochargers can withstand a transient pressure increase of 12 bar. After an event, verify casing positions, bearing casing shifting, and check for cracks. Bearings should be inspected before the next start if anomalies are found or a strong deflagration occurred.
Lifting Loads: Use appropriate lifting gear with sufficient load limits. Attachment angles should not exceed 45°. Components must be cooled to a maximum of 80°C before looping.
Pre-lubrication/Post-lubrication: Pre-lubrication is required for at least 5 minutes before starting. Post-lubrication is at least 10 minutes, unless the engine runs for 5-10 minutes in idle mode before stopping.
Flexible Turbocharger Cut-out: For engines with multiple turbochargers, one can be switched off at low loads. Lubricating oil supply to the switched-off turbocharger must not be cut off. External sealing air must be supplied. Switching on/off should only occur when the engine is stopped or in idle mode, and below charging pressures of 0.3 bar.

Maintenance Features:

Periodic Maintenance: Includes regular visual controls and cleaning of the filter silencer, compressor, turbine, and nozzle ring.
Service Intervals:
- Every 25-50 hours: Visual check for leaks, record operating data, and investigate deviations.
- Every 100 hours after commissioning: Clean or replace oil filter in the supply pipe.
- Every 18000 hours: Recommended service by ABB Turbocharging Service Station. Includes removing/cleaning filter silencer, dismantling wall insert, checking axial clearance A, cleaning compressor wheel/diffuser/casings, checking nozzle ring/turbine diffuser/blades for contamination/damage/wear, fitting wall insert, and installing filter silencer.
- Every 36000 hours: Service on rotor and bearing parts by ABB Turbocharging Service Station. Includes removing/cleaning filter silencer, dismantling wall insert, checking axial clearance A, cleaning wall insert/diffuser/compressor casing, removing gas inlet casing/nozzle ring/cover ring, cleaning nozzle ring/cover ring, dismantling/inspecting/balancing rotor, and replacing plain bearing.
- Every 5 years (after last service): Recommended inspection by ABB Turbocharging Service Station to prevent machine damage.
Compressor Cleaning (Wet Cleaning): Performed during operation with pure water at engine loads between 25-85%. Not recommended if air inlet temperature is below 0°C. Never use salt water.
Turbine Cleaning (Dry Cleaning): Performed during operation using granulated materials (hard, soft-blast, or activated carbon particles) at engine loads of 5-85%. Granulate average grain size 1.2-2.0 mm, specific weight max 1.2 kg/dm³.
Draining Gas Outlet Casing: Procedure for draining water from the gas outlet casing in case of boiler leaks or water ingress.
Troubleshooting: Provides tables for malfunctions during starting, operation, and stopping, including possible causes and remedies.
Emergency Repairs: In emergencies, the rotor can be locked. The permissible turbocharger speed for an unlocked turbocharger must not exceed nBmax. After locking, contact an ABB Turbocharging Service Station.
Mothballing: For engine shutdown up to 12 months, if lubricating oil acid number (TAN) < 2 mg KOH/g, no special measures are needed if preservative oil is used. If TAN > 2 mg KOH/g, dismantle turbocharger, clean all parts, coat plain surfaces with anticorrosive oil, and have rotor/bearing parts serviced by ABB. For shutdowns longer than 12 months, seal all openings with paraffin paper and wooden lids, and store in dry rooms (40-70% atmospheric humidity). Annual corrosion checks are required.