Design The Electrical Motor Design Guidelines contains design criteria and specifications used in the procurement of electrical 3-phase AC induction motors. Table of Contents 1. Introduction 2. Design 3. Installation 4. Products or Material 5. Summaries 1. Introduction Consider all standards described in this document mandatory unless otherwise identified as optional or preferred. Any variance from GMI requirements or preferences requires prior GMI Engineering approval. Obtain approval from the engineer that issued this document or has been designated as responsible for project deliverables. GMI will provide and document specific project requirements and approvals. 2. Design Use the following standards for system design and performance requirements. Motor Enclosures o Dry Locations: Enclosures shall be rolled steel band or cast iron construction depending on horsepower. End brackets shall be die cast aluminum with steel bearing inserts or cast iron construction. o Wet Locations: For motors installed in environments where iodine based sanitizers or alkaline cleaners might be used. Epoxy coated cast iron or stainless steel motors must be used. o Conduit box shall be die cast aluminum or cast iron construction. In wash down applications junction boxes must be stainless steel and have neoprene gaskets. o NEMA frame motors shall be used. CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 1
Design o Avoid using metric motors. If you use metric motors, design the machine frame to allow for retrofitting with a standard motor when the original metric motor fails. o Use only UL listed (CSA in Canada) motors. Explosion-proof and dustignition-proof motors must carry Underwriters Laboratories Certification. o Permanently attach a stainless steel motor nameplate to the motor frame that includes a unique motor serial number that can be used to identify the motor and track its history throughout its service life. Make sure the nameplate shows nominal and minimum guaranteed full load efficiency. Motor Electrical o Motor voltage level to nominal 480 Volt, 3 Phase, 60 Hertz (600 Volt, 3 Phase, 60 Hertz in Canada). o For winding insulation system for general purpose motors, use NEMA Class F (or better) with maximum of 80 C temperature rise (by resistance) in any phase of the starter winding at full rated horsepower load. o Windings shall be copper magnet wire rated at 200 C and moisture resistant. Magnet wire insulation varnish must be of a type designed to resist transient spikes (such as Inverter Spike Resistant ISR), high frequencies, and short time rise pulses produced by inverters. Motor insulation system shall comply with NEMA MG1-1998 Part 31.4.4.2. o Variable speed applications must be designed not to exceed the motor operating frequencies of 30Hz and 90Hz with the nominal base speed of 60HZ under operation rates. o All variable motor speed must have a turndown rate of 10:1, unless an application requires a greater speed ratio on the motor. o DC motors shall rarely be used. They require GMI Engineering approval. Motor Mechanical o Design motor service factor to minimum 1.15. CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 2
Design o Motors must comply with NEMA MG1, Table 12-12, NEMA Premium efficiency levels, such as 1 HP, 1800RPM, Efficiency >85.5%, EISA 2007. o When coupling the motor to a gear reducer use NEMA C or D frame motors to gearbox flange systems. Integral motor-gearbox combinations require GMI Engineering approval. o Variable speed motors when used in combination with a gear reduction must have a nominal speed the motors name plate at normal application design rates. o GMI prefers sealed-for-life bearings for all motors operating at ambient temperature and normal speeds. o For motors with greasable bearings, provide lubrication instructions that specify the lubrication frequency, amount, and type. If possible, provide this information on the motor name plate. o Do not use motors smaller than one-half HP. o Size motors to run at no more than 90% of nameplate rating. o Mechanical variable speed drives are not allowed. All motors furnished shall be designed, manufactured, and tested in accordance with the latest applicable standards of NEMA, ANSI, IEEE, and ASTM. As a minimum requirement, all motors shall conform to the latest applicable sections of NEMA No. MG-1. Servo Motors Specification, refer to CIS_303_Servo_Drive_Design WHQ.docx 3. Installation Use the following guidelines for installation. Do not install more than three motor power feeds sharing the same conduit. For 480 volt motor and power feed wire, use NEC type THHN, minimum size 14 AWG, stranded, with 600 volt insulation and 90 C temperature rating. Use only continuous (non-spliced) cable from the drive to the load. CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 3
Design Physically connect a grounding wire to the motor frame using a solderless connection. Use the following connections based on motor size. 10 HP or less use 3M Scotchloks Electrical Spring Connectors or comparable type wire nut. 11 75 HP use crimped terminals that are bolted together and taped with layers of rubber to remove all sharp edges. Cover with a minimum of three layers of Scotch 33+ or similar vinyl electrical tape. Over 75 HP use compression terminals applied with a hydraulic crimping tool. Apply an initial layer of Scotch 33+ prior to the insulation putty or rubber. Use ample insulation putty and rubber to smooth all sharp edges prior to covering the connection with at least three layers of Scotch 33+. GMI permits flexible conduit (Sealtite) or jacketed cable (SO type cord) for field connection to the motor. Keep the length of the flexible conduit as short as possible and always less than 36 inches. Make sure each motor has individual short circuit protection and running overcurrent protection on all phases of a three phase system or on the hot side of a single phase motor. Leave the weep holes in the lowest part of the motor open. Plug all other weep holes. Install a local motor disconnect switch on all motors. Make each local motor disconnect switch lockable and suitable as a safety device in compliance with GMI s lockout tagout (LOTO) program. Furnish the local disconnect with an auxiliary contact wired to a PLC input. The preferred disconnect switch is either a Hubbell HBLDS#AC (where # is 3 [30A], 6 [60A], or 10 [100A]) or an Allen- Bradley 194E-CaxxE-P11 (where xx is related to the load size). Plan for integration of motor control with the human machine interface (HMI), including operation and status displays, fault handling routines, and troubleshooting features. GMI will provide HMI templates with diagnostics, alarms, and status indications during process design. CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 4
Design 4. Products or Material Use the following motor manufacturers. Dry location o Baldor, Super-E, Inverter Ready Washdown o Baldor, Washdown Duty Motor, Inverter Ready Gearhead o Stober, Helical/Bevel CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 5
Design 5. Summaries Enter information in these tables to track revisions to the master document. NOTE: In the Entry column, enter your information between the dashes. The entries automatically update matching document properties. Document Property Entry Master Owner -Daniel Migliori- Increment revision numbers Master Number -1- by one. Master Date -11/30/2009- Number Date Owner Summary (Brief description of major changes) 0 10/3/2005 Daniel Migliori Original Development 1 11/30/2009 Daniel Migliori Major changes to incorporate GMI Motor Spec dated March 1999 CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 6
Design 5.1 Plant Customization Tracking Enter information in these tables to track revisions to plant customized documents. NOTE: In the Entry column, enter your information between the dashes. The entries automatically update document properties. Document Property Entry Plant Code -XXX- Use the following format for Plant Owner -Enter Namethe Plant Number: Plant Number -0.0- <Master Number>.<Plant Plant Date -3/29/05- Number> Number Date Owner Summary (Brief description of major changes) 0 3/28/2005 CIS_301_Electric_Motor_Design WHQ.docx, 1, November 2009 7