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General Purpose Gear Units | Rotating Equipment Engineering

1. PURPOSE……………………………………………………………………….2. GENERAL 3. ADDENDA The following section, subsection numbers refer to API 677
Section 1 – General …………………………………………………………1.1 Scope 1.3 Conflicting Requirements 1.5 Referenced Publications …………………………………
Section 2 – Basic Design 2.1 General 2.5 Casings………………………………………………………..2.6 Casing Connections
2.7 Gear Elements 2.9 Bearings……………………………………………………….2.10 Lubrication
Section 3 – Accessories 3.2 Couplings and Guards ……………………………………3.3 Mounting Plates
Section 4 – Inspection Testing, and Preparation for Shipment 4.1 General ………………………………………………………..4.2 Inspection 4.3 Testing 4.4 Preparation for Shipment ………………………………..
Section 5 – Vendor’s Data 5.3 Contract Data

1. Purpose

American Petroleum Institute (API) Standard 677, Second Edition, July 1997 is adapted as a SABIC
Engineering Standard with the following addendum.
2. General
2.1 Gear units manufactured to this standard shall conform to API 677, Second Edition, except as modified
herein or as set forth on Data Sheets, Project Specifications, or Purchase Order.
3. Addenda
The following section, subsection, paragraph numbers refer to API 677, Second Edition.
Section 1 – General
1.1 Scope
1.1.3 Add the following new paragraph:
General purpose gear units shall be supplied by vendors qualified by experience in manufacturing the
proposed units. To qualify, the vendor shall have manufactured at least two gear units of comparable
power rating, pinion speed, speed ratio and pitch line velocity. These gear units shall have completed at
least 8000 h of continuous operation satisfactorily.
1.3 Conflicting Requirements
Add the following new paragraph:
Any conflict(s) between this standard, SES and industry standards, engineering drawings, and contract
documents shall be resolved at the discretion of SABIC.
1.5 Referenced Publications
1.5.1 Add the following standards:
The following standards are part of this addendum. The latest issues, amendments and supplements to
these documents shall apply, unless otherwise indicated.
G03-S01 Lubrication, Shaft Sealing, Control Oil Systems and Auxiliaries
G12-S01 Special Purpose Couplings
G19-S01 Machinery Protection Systems
S20-G01 Plant Equipment Noise Levels
Section 2 – Basic Design
2.1 General
2.1.5 Modify the first sentence as follows:
Control of the sound pressure level to meet specified requirements shall be the sole responsibility of the
vendor. See SES S20-G01.
2.1.14 Add the following paragraph:
Unless otherwise specified, gear units and auxiliaries shall be designed for unprotected outdoor
installation. Specific site climatic conditions shall be used for gear units and auxiliaries design. A minimum
of the following shall be required:
a. Dust seal or cover
b. Filter for breather or vent caps.
2.1.18 Add the following new paragraph:
Splash lubricated gear units (non cooled / non pressurized) are acceptable up to 37 kW (50 HP).
2.5 Casings
2.5.1 Design Parameters

2.5.1.1 Add the following paragraph:
The gear units shall be designed to ensure accurate realignment after disassembly.
2.6 Casing Connections
2.6.1 Service and Size Criteria
2.6.1.3 Add new paragraph:
Casings shall be provided with an inlet purge connection at least ½ inch NPT, located to assure a sweep of
purge gas across the casing to the filter-breather.
2.7 Gear Elements
2.7.1 General
2.7.1.5 Modify the second sentence as follows:
Overhung designs shall not be acceptable.
2.7.2 Quality Assurance
2.7.2.5 Add the following new paragraph:
Gear materials shall be checked for proper hardness after rough machining. For gears above 746 kW
(1000 hp), the vendor shall submit chemical and physical property tests certificates for all forged gear
blanks. These certificates shall be based on test pieces attached to, or taken from the gear forgings, and
shall accompany the forgings throughout the heat-treating cycle.
2.7.4 Shafts
2.7.4.2 Add the following paragraph:
Unless otherwise specified, all gear units above 746 kW (1000 hp) rating shall be installed with API 670
type radial vibration and axial.
thrust probes. All gear units above 37 kW (50 hp) shall have provisions for mounting accelerometer
pickups.
2.9 Bearings
2.9.3 Thrust Bearings
2.9.3.2.1 Add the following sentence:
Equal thrust load capability shall be required for double helical gears.
2.10 Lubrication
2.10.7 Add the following paragraph:
The lube oil system shall be supplied by the vendor having unit responsibility for the equipment train.
Section 3 – Accessories
3.2 Couplings and Guards
3.2.7 Add the following paragraph:
Couplings operating at a speed more than 3800 RPM shall conform to API 671 for component balancing
and assembled balance check.
3.3 Mounting Plates
3.3.1 General
3.3.1.1 Add the following paragraph:
The gear unit shall be mounted flush on a machined mounting plate. The gear unit shall be the benchmark
to which all other equipment is aligned.

Section 4 – Inspection, Testing, and Preparation for Shipment
4.1 General
4.1.9 Add the following new paragraph:
QA inspection, testing, and documentation shall be in accordance with General Purpose Gear Units data
sheets. Witnessed inspection(s) or test(s) shall be prearranged with SABIC.
4.1.10 Add the following new paragraph:
All tests, witnessed or not, shall be certified by the vendor.
4.2 Inspection
4.2.3 Welds in Rotating Elements
4.2.3.1 The decision is as follows:
All welds in rotating elements and those attaching gears to shafts shall receive 100 percent inspection.
4.3 Testing
4.3.1 General
4.3.1.4 Add the following paragraph:
All gear units supplied with a pressure lubrication system shall be tested with the gear’s mated job oil
system.
4.3.3 Mechanical Running Test
4.3.3.1 Add the following paragraph:
Temperature and vibration of bearings at the end of the run shall be the same as those at the beginning of
the run. Gears driven by a stream turbine shall be run at 110% of the maximum allowable continuous
speed for a minimum of 15 minutes.
4.3.4 Optional Tests
4.3.4.1 Add the following paragraph:
Unless otherwise specified, vibration limits shall be as per 2.8.3.
4.4 Preparation for Shipment
4.4.1 Modify the third sentence as follows:
The preparation shall make the equipment suitable for outdoor storage for 12 months from the time of
shipment, with no disassembly required before operation, except for inspection of bearings and seals.
Section 5 – Vendor’s Data
5.3 Contract Data
5.3.1.1 See Appendix E; Description, Item 21. Add the following paragraph:
Certified shop logs of the mechanical running tests shall also have the following:
(i) Percent tooth contact
(ii) Speed
(iii) Vibration
(iv) Temperatures
(v) Oil Pressures

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