Attachment_B_-_Specifications,_Non-Inverter_Duty_Motors_2024.doc

Bid No. 6293

Specifications

IFB 6293A

Specifications

Specifications for Non-Inverter Duty Motors

1. General All workmanship and materials shall conform to the latest NEMA and EASA standards.

The vendor shall have a working quality assurance program in place and shall provide a copy of the quality manual for review.

The vendor shall provide the supervision, labor, engineering, materials, test equipment, tools and facilities required to inspect and repair the equipment described in this specification.

2. Mechanical (Repair)

a. Shafts

(1) Shall be checked for undue wear, scoring and straightness.

b. Bearing Journals and Shaft Extension

(1) Bearing journals and shaft extension shall be concentric with shaft centers.

(2) Shaft runout for standard length shaft shall not be more than .002 inch for 5/8 to 1-5/8 inch diameter and shall not be more than .003 for larger than 1-5/8 inch.

c. Bearings

(1) All replacement bearings must be free from defect and surface wear.

(2) Must be properly installed and aligned.

(3) All replacement bearings must be equal or better than original bearing with regards to load and life characteristics.

(4) Clearance shall be sufficient to allow thermal expansion of motor parts.

(5) When new bearings are installed, the old bearings SHALL be returned with the repaired motor in order to ensure payment for the new bearings.

d. Balancing

(1) Vibration amplitude shall conform to limits established by original manufacturer of motor, and ISO standards.

3. Electrical (Rewind)

a. All rewound equipment must produce same torque, speed, horsepower, efficiency, power factor, and temperature characteristics as the original winding unless owner authorizes a design change.

b. Insulation

(1) The entire insulation system shall be equal or better than original system used by original manufacturer.

(2) Shall be Class F or better.

(3) All components that constitute an insulation system shall be compatible with each other and the varnish or coating applied.

(4) All materials used shall be of the proper NEMA temperature class to meet the required temperature use of the apparatus.

(5) Special attention should be given to motors used in variable frequency drives (see Inverter Duty Motors VFD Specification for details).

(6) Required temperature rise must be met after derating installed insulation to conform to the minimum frequency of operation.

(7) Stators shall be dipped and baked a minimum of two (2) times.

(8) Magnet wire - all capacities, mechanical qualities, insulation characteristics shall be equal or better than original material in all aspects of performance and application with a minimum of Class F being used.

(9) Lacing and Shaping

(a) The coil ends shall be particularly laced and shaped to maintain all necessary clearances such as rotor, end shields, and through bolts, and be able to endure starting and running currents with a minimum of distortion.

(b) On larger motors where coil support (surge) rings are used, they shall be suitably fitted and laced to ensure adequate support for the winding.

(c) On larger motors where coil support (surge) rings are used, they shall be suitably insulated, accurately fitted and laced to ensure adequate support for the winding.

(d) All lacing and shaping shall be done in a neat and workmanlike manner.

(10) Connections

(a) All connections shall be properly soldered, brazed, or welded with materials that will be mechanically strong enough to withstand the normal operating conditions.

(b) Materials such as solder paste, fluxes, inhibitors, and compounds, where employed, shall be neutralized after using.

(c) Shall be suitable for the use and of a type that will not adversely affect the conductors.

(d) All connections and splices shall be so constructed as to have a resistance equal to or less than the conductors of the winding.

(e) Connections to terminal shall be of the type approved by the National Electrical Code that shall ensure a good electrical and mechanical contract without injury to the conductors.

(11) Insulating Connectors

(a) All connections are to be adequately insulated with materials that will withstand the temperature, voltage and frequency rating of the apparatus and be mechanically adequate to withstand normal operation.

(b) All connections and leads shall be laced, tied, or otherwise securely fastened to prevent movement and subsequent failure.

(c) All connections shall be made and insulated in a neat and workmanlike manner.

(12) Banding

(a) Glass banding tape may be applied directly to the winding.

(b) Banding shall be applied at proper tension and be of sufficient thickness and width to support the coils to minimize distortion.

(c) When banding wire is used, it shall have a tensile strength of no less than 2,000 psi.

(d) Area to be banded shall be properly insulated. Banding wire shall be applied at the proper tension.

(e) All types of bands shall be sufficiently secured, tied, or laced and be mechanically strong enough to withstand the centrifugal force, current surges and vibrations of normal operation.

(13) Thermal Procedures

(a) Thermal protectors shall be checked for electrical and physical defects.

(b) Replacement of protectors shall be identical with the original in tripping characteristics.

(c) Removal of protectors shall be done with City consent or manufacturer approval.

(14) Random Wound Coils

(a) Loops shall be made and spread to form coils without damage to the magnet wire insulation.

(b) Application for layer insulation shall be uniformly and tightly applied to eliminate stress points and air voids.

(c) Insulated coils shall be placed in slots with no damage to the coil insulation.

(d) Coils shall tightly fit slots.

(e) Coils shall be secured to surge ring and locked to one another as necessary to prevent distortion.

(15) Inspection

(a) The condition of the winding and the extent of the repairs shall be determined by visual inspection and, as necessary, a megohmmeter reading, phase unbalance or surge comparison, growler test, and/or appropriate high potential ground test.

(b) Winding data shall be accurately taken and recorded.

(c) Stators that are cleaned using a burnout oven shall use an oven with a temperature control that prevents the inside temperature from rising above 400 C to prevent damage to the stator.

(d) Stators shall be properly stripped and prepared for winding.

(e) Slots shall be clean and free of sharp edges or particles.

(f) Laminations shall be inspected for damage.

(16) Leads

(a) All leads shall conform to NEMA standards.

(b) Single phase motors use lead colors instead of letter markings to identify the leads, the color assignment shall be determined from the following:

T-1 Blue T-5 Black

T-2 White T-6 Red

T-3 Orange P-1 No Color

T-4 Yellow P-2 Brown

(c) Leads on TEFC and explosion proof motors shall be properly sealed to meet environmental operation conditions.

(d) On motors where multiple leads are available, ALL leads will be pulled out and identified with metal markers (3 phase = 9 leads, 1 phase capacitor motors = 4 leads).

4. Testing

a. General

(1) The condition of new winding shall be tested by the following methods as applicable.

b. Ground Tests

(1) Megohmmeter reading of windings shall be made and recorded.

c. Winding

(1) Tests for winding shall be made by phase balance, surge comparison, growler, resistance, voltage drop and over potential test.

d. Explosion Proof

(1) Motors are to be recertified for use in hazardous locations, under the guidelines of Underwriters Laboratories.

e. No Load Tests

(1) No-load running tests shall be made at rated voltage, when possible.

(2) No-load current and speed shall be recorded and the mechanical operation checked.

f. Full-Load Tests

(1) Full-load tests may be made as arranged with the City or as necessary to check the operating characteristics of the apparatus.

(2) Random winding

(3) Form winding

3-6 3-7