Regal Rexnord Thomas XTSR Series

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F O R M

Thomas

XTSR71 Installation and

Maintenance Manual • Sizes 494-5258

CP3-001E

Revised

June 2023

Industrial Powertrain Solutions

Regal Rexnord

Application Engineering: 800 626 2093

PTSAppEng@regalrexnord.com

rexnord.com/couplings

Indicates a hazard which, if not avoided, will result in

serious injury or death.

Indicates a hazard which, if not avoided, could result

in minor or moderate personal injury.

Indicates a hazard which, if not avoided, could result

in serious injury or death.

Indicates information considered important, but not hazard-

related (e.g. messages relating to property damage).

• The coupling should be stored in a dry corrosion protected

environment, free from external loads (for example by stacking) to

prevent damage which may cause a hazard when the coupling is put

into service.

• For ATEX requirements the guard must have a minimum of 12.7 mm

(1/2 in) radial clearance to the coupling outside diameter and allow for

proper ventilation.

• All conductive parts of the equipment should be connected in such

a way that hazardous electrical potential differences cannot occur. In

case insulated metal parts could be charged thus becoming a potential

ignition source, earth connections must be provided.

• All work on the coupling must be performed when the coupling is at

rest with no load.

• Do not start or jog the motor, engine, or drive system without securing

the coupling components. If the equipment is started with only a hub

attached, the hub must be properly mounted and ready for operation,

with the key and set screw (if included) fastened. When the full

coupling assembly is started, all fasteners and hardware must be

completely and properly secured. Do not run the coupling with loose

fasteners.

• Use explosive environment appropriate tools only, for more information

see DIN EN 1127-1:2008:02, Annex A.

• The coupling may only be used in accordance with the technical data

provided in the Thomas disc coupling catalog. Customer modiﬁcations

and alterations to the coupling are not permissible.

• Safety should be a primary concern in all aspects of coupling

installation, operation, and maintenance.

• Proper lockout/tagout procedures must be followed to safeguard

against unintentional starting of the equipment.

• Make sure to disengage the electrical power and any other sources

of potential energy before you perform work on the coupling.

• Do not make contact with the coupling when it is rotating and/or in

operation.

• Because of the possible danger to person(s) or property from

accidents which may result from improper use or installation of these

products, it is extremely important to follow the proper selection,

installation, maintenance and operational procedures.

• Installation should be carried out by skilled personnel only.

All personnel involved in the installation, service, operation,

maintenance, and repair of this coupling and the connected

equipment must read, understand, and comply with these

Installation and Maintenance instructions. The Installation and

Maintenance instructions and assembly drawing, if provided, must

be at hand at the installation site.

• Packaging material can generate electrostatic charges. It may then

become an explosive hazard. It must be removed from the coupling

outside any hazardous areas.

• All rotating power transmission products are potentially dangerous

and can cause serious injury. They must be properly guarded in

compliance with OSHA, ANSI, ATEX, European machine safety

standards and other local standards. It is the responsibility of the

user to provide proper guarding.

• For this coupling to meet the ATEX requirements, you must precisely

follow these installation and maintenance instructions, and the

supplement form 0005-08-49-01. This supplement outlines the ATEX

requirements. If the operator does not follow these instructions, the

coupling will immediately be considered non-conforming to ATEX.

GENERAL SAFETY INSTRUCTIONS

• All spare parts for service or replacement must originate from or be

approved by Rexnord.

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The Thomas® XTSR71 is a flexible disc coupling designed to provide a mechanical connection between the rotating shafts of mechanical equipment. It utilizes flexible discs to accommodate inherent misalignment while transmitting power and torque between connected shafts.

Function Description:

The primary function of the XTSR71 coupling is to transmit power and torque between two shafts while compensating for axial, parallel, and angular misalignments. The design incorporates flexible discs that allow for this flexibility without requiring lubrication, making it a low-maintenance solution. The coupling is delivered from the factory with a fully assembled center member, including a center spool, two adapters, disc packs, bolts, bushings, and locknuts, pre-tightened to specified torques, ready for field installation.

Important Technical Specifications:

The XTSR71 series covers a wide range of sizes from 494 to 5258, with various "C" lengths for the center spool (ranging from 3.50 inches to 9.00 inches, or 100 mm to 250 mm). It supports different hub and cap screw kit part numbers, as well as hardware kits for disc packs. The coupling is designed to meet ATEX requirements, necessitating strict adherence to installation and maintenance instructions, including specific clearances for guards (minimum 12.7 mm radial clearance) and proper ventilation in explosive environments.

Shaft alignment is critical for optimal performance and coupling life. The manual provides installation limits for angular and parallel alignment, with total indicator readings (TIR) for angular alignment (X-Y measurements between opposite sides of the center spool flange and adapter flange) and parallel alignment (P, offset between hub centers). For example, a size 494 coupling has a maximum angular alignment TIR of 0.004 inches (0.10 mm) and a maximum parallel alignment of 0.004 inches (0.10 mm). Larger couplings, such as size 5258, have higher tolerances, with a maximum angular alignment TIR of 0.024 inches (0.61 mm) and a maximum parallel alignment of 0.024 inches (0.61 mm).

Locknut tightening torques are specified in Table 5, varying by coupling size and bolt size. For instance, a size 494 coupling with M5 bolts requires 4.7 ft-lb (6.4 Nm) of torque, while a size 5258 coupling with M48 bolts requires 4900 ft-lb (6700 Nm). These values are approximate for steel bolts with lubricated threads.

Usage Features:

Installation: The XTSR71 is designed for straightforward installation. Hubs can be mounted using either a straight bore with clearance/slip fit or an interference fit (taper bore or straight bore). For interference fits, heating the hub in an oven (preferably, to 350°F/177°C for carbon steel hubs, not exceeding 500°F/260°C) is recommended to expand the bore for easier installation. Set screws, if used, must be tightened to specified torques (Table 2).
Alignment: Proper shaft alignment is crucial for minimizing distortion of the flexing elements and extending coupling life. The manual details methods for measuring angular and parallel alignment, recommending laser alignment, reverse dial indicator, and rim and face methods. The center member subassembly is designed to be compressed to fit between the two end hubs, and cap screws are used to secure the assembly.
Safety: General safety instructions emphasize lockout/tagout procedures, disengaging electrical power, avoiding contact with rotating parts, and ensuring proper guarding in compliance with OSHA, ANSI, ATEX, and other local standards. Packaging material can generate electrostatic charges and must be removed outside hazardous areas. Only skilled personnel should perform installation and maintenance.
ATEX Compliance: For ATEX environments, specific requirements must be met, including adequate guard clearance, proper ventilation, and earth connections for all conductive parts to prevent hazardous electrical potential differences. Only explosive environment-appropriate tools should be used.

Maintenance Features:

Storage: The coupling should be stored in a dry, corrosion-protected environment, free from external loads to prevent damage.
Lubrication: All bolts and cap screw threads must be lubricated with clean motor oil prior to assembly. Lubricants containing molybdenum disulfide or greases are not recommended.
Disc Pack Replacement: The manual provides detailed instructions for disassembling and reassembling the center member when replacing disc packs. This involves removing locknuts, bolts, and disc packs, then installing new components in a specific sequence, ensuring proper alignment and tightening of locknuts to the specified torque using an alternating progressive pattern (Figures 13 and 14).
Post-Installation Check: After initial installation, it is recommended to check the tightening torque of all locknuts after several hours of initial operation.
Spare Parts: All spare parts for service or replacement must originate from or be approved by Rexnord to ensure continued performance and compliance.

The XTSR71 coupling is a robust and reliable solution for power transmission, designed with an emphasis on safety, ease of installation, and long-term performance, especially in demanding environments requiring ATEX compliance.