This article is about Severe Duty TE Motor Material Requirement, Selection Guide & Technical Specification of LV SQUIRREL CAGE INDUCTION MOTOR for commercial buildings, plants and refinery projects as per international codes and standards.
LV SQUIRREL CAGE INDUCTION MOTOR MATERIAL TECHNICAL REQUIREMENTS
| QC Before Installation- Motors shall conform to all applicable requirements, standards, and specifications prior to release to be used as part of work. |
| Incoming motors shall be visually inspected for damage / defects occurred during transportation. |
| Motors shall be new and unused. |
| Motors shall be in accordance with the approved project-specific design drawings, diagrams, schedules, lists, databases, and associated design documents. |
Check that the motors are supplied from the approved manufacturer’s as per Regulated Vendors List for Electrical Equipment.
A name plate shall be provided and the information given thereon shall include the following:
a) Frame size
b) Full load speed
c) Full load current
d) Locked rotor current at full voltage
e) Maximum noise, sound power level: 90 dBA
f) Insulation system Class F minimum
g) Temperature rise at rated load: 80° C maximum
h) Service factor
i) Guaranteed minimum efficiency at full load
j) Terminal box(es) material of construction
k) Fan material
l) Other data
Sec. 12.2, IEEE Std 841-1994 Edition June 06,1994
| Enclosures shall be TEFC or totally enclosed non-ventilated (TENV) having a degree of protection of IP54. IEEE Std 841-1994, Sec. 4.5 |
| Motor shall be applied within their rating based on a 1.0 SF (service factor) in a maximum 50º C ambient temperature. IEEE Std 841-1994, Sec. 4.1 |
| Motors exposed to ambient temperatures shall be rated in accordance with NEMA MG 1 as modified by this standard, 17-SAMSS-502, 17-SAMSS-503, 17-SAMSS-510, 17-SAMSS-518, or 17-SAMSS-520, as applicable, for a 50 deg C ambient. Motors shall be applied and sized based on their 1.0 service factor rating. |
| Exceptions: Motors suitable for a 40° C ambient are permitted, with the approvals, for sites listed in SAES-A-112 as having a Monthly Normal Maximum Temperature of 35° C or less. Motors in an air conditioned environment where the air conditioning equipment has a designed temperature of 35° C or less may be rated for use in a 40° C ambient. |
| Exceptions: Induction motors built to the requirements of 17-SAMSS-503 which are rated and marked for operation at 1.15 service factor in a 40° C ambient are accepted as equivalent to motors rated for operation at 1.0 service factor in a 50° C ambient. Provided that they meet all requirements of 17-SAMSS-503, including requirements for satisfactory operation in a 50° C ambient with a winding temperature rise of 70° C (120° C total temperature). |
| Commentary Notes 5.6: Motors covered by 17-SAMSS-502, 17-SAMSS-503 and 17-SAMSS-520 and/or this standard are required to meet the criteria forClass F insulation, with an allowable temperature rise, above the ambinent of 50°C, to not exceed that listed for Class B insulation in NEMA MG 1, Part 12, Part 20 or Part 21, ANSI C50.13 or IEC 60034-1 limits as applicable. |
| Motors rated 0.746 KW (1 HP) and above shall comply with 17-SAMSS-502, 17-SAMSS-503 or 17-SAMSS-520. |
| Exceptions: Unless specified, 17-SAMSS-503 does not apply to motors supplied as an integral part of manufacturer’s standard packaged parent equipment such as exhaust fan ventilation assemblies and air conditioning units which meet standards recognized by Saudi Aramco. The specifications listed in Paragraph 6.1 may not apply to motors for special purpose applications, such as starter motors for gas turbine driven generators. Refer to the Electrical Standards Committee Chairman for determination. |
| Motors shall be selected in accordance with Table 1. (See Attachment-1) |
| Motors rated less than 0.746 KW (1 HP) shall comply with NEMA MG 1 and the following additional requirements: a) Motors for exposed outdoor installation shall be of the totally enclosed type and rated in accordance with NEMA MG 1 for a 50 deg C ambient and a Class B winding temperature rise. b) Motors for indoor installation shall be totally enclosed or of the drip proof guarded type. c) The insulation system shall be Class F minimum. d) Enclosures and terminal housings shall be metallic. e) Single Phase Motors shall be provided with a built-in-thermal protective device. f) Fans shall be metallic or reinforced fiberglass, and shall be designed for dual rotation. |
| This specification shall only be used for motors rated from 0.75 kW (1 HP) up to and including 185 kW (250 HP), at 460 V and below, as well as motors rated between 185 kW (250 HP) and 370 kW (500 HP), at 4000 V. |
| Motor shall be suitable for operation in accordance with their rating while exposed to ambient temperatures in the range of 0º C to 50º C. |
Motors supplied under this specification shall comply with the following table:
| Motors shall be fitted with replaceable shaft seals of the non-contacting while rotating type. Seals shall be fitted on both the drive end and non-drive end of the shaft. |
| Data for motor over 100 HP shall include the following: Horsepower rating; Nameplate voltage; Full load current; Locked rotor current; Acceleration time; Permitted stall time at 80%,90%,100%and 110% rated voltage; Thermal capability curves; Number of starts allowed, from cold in first hour and subsequent hours; After a running trip, starts allowed in first hour and subsequent hours. If acceleration time exceeds permitted stall time, data on speed switch and times shall be provided; RTD data. |
| Motors rated 75 kW (100 HP) and above shall be equipped with space heaters. |
| Motors less than 75 kW (100 HP) shall be equipped with space heaters if specified in Data Schedule 1. |
International Codes & Standards
| 1. SAES-P-101 Regulated Vendors List for Electrical Equipment. |
| 2. SAES-P-113 Motors and Generators. |
| 3. SAES-P-114 Power System and Equipment Protection. |
| 4. 17-SAMSS-503 Severe-Duty Totally Enclosed, Squirrel Cage Induction Motors to 250 HP |
| 5. IEEE Std 841-1994 Severe Duty Totally Enclosed Fan-Cooled (TEFC) Squirrel Cage Induction Motors -Up to and Including 500 hp |