Sources and safety

The Motor Learning Center is based on published manufacturer and industry documents. It is general education, not a repair manual.

Safety guidance

Do

  • Switch off a motor that is behaving unusually, and keep it isolated from its supply.
  • Note what you saw, heard and smelled, and when it happened. It helps the person who assesses it.
  • Keep people away from rotating parts and from equipment that may start automatically.
  • Leave electrical testing, terminal-box work and dismantling to qualified people with the right equipment.

Don’t

  • Don’t keep resetting a breaker, fuse or overload relay that has tripped without finding out why.
  • Don’t bypass, bridge or adjust protective devices to keep equipment running.
  • Don’t open covers or touch connections on equipment that may be energised.
  • Don’t keep running a motor that smells burnt, smokes, or makes a new, harsh noise. Stop it and have it checked.

Manufacturer manuals repeatedly state that installation, maintenance and troubleshooting are for qualified people. Follow your site’s lock-out rules (locking the power off before anyone works on equipment), its electrical safety rules, and the equipment manufacturer’s instructions.

Sources

  1. ABB

    Low voltage motors: Installation, operation, maintenance and safety manual

    3GZF500730-85 Rev H, June 2022. Link checked 17 October 2026.

    Sections used:

    • §1–2 Introduction and safety: installation and use by qualified personnel (pp. 5–6)
    • §3.1 Reception: winding connection, star or delta (p. 7)
    • §4.3 Insulation resistance check; §4.4 Foundation (p. 10)
    • §4.5–4.7 Coupling halves and pulleys, alignment, belt drives; airflow clearance at the fan cover (p. 11)
    • §4.8 Drain plugs for condensation; §4.9 Cabling, terminal box and earthing (pp. 12–13)
    • §6.2 and Table 6.1 Winding insulation with converters; §6.4 Bearing currents (pp. 15–16)
    • §6.7 Motors in variable speed applications: loadability (p. 17)
    • §7.1 Maintenance, general inspection (p. 19)
    • §8 After sales support: rewinding by qualified repair shops; bearing removal and fitting (p. 23)
    • §10 Troubleshooting, Table 10.1 (pp. 25–26)

  2. ABB

    Low voltage motors: Motor guide

    9AKK105285 Rev D, July 2019. Link checked 17 October 2026.

    Sections used:

    • §4.1 The induction motor: rotating field, rotor bars, slip (p. 33)
    • §4.2 Insulation: thermal classes; temperature and insulation lifetime (p. 34)
    • §4.5 Starting methods: direct-on-line, star-delta, softstarters (pp. 36–37)
    • §5.1 Motor construction: stator, rotor, shaft, bearings (p. 59)

  3. EASA

    Good Practice Guide to Maintain Motor Efficiency

    Version 1021 (2021), based on the 2019 and 2003 EASA/AEMT rewind studies. Link checked 17 October 2026. Free download from the EASA resource library page linked here.

    Sections used:

    • Introduction: purpose and scope, three-phase random-wound motors (p. 1)
    • Core losses and interlaminar insulation; core loss testing (pp. 2, 4)
    • Stray losses: core damage during winding removal, burnout temperature (p. 7)
    • §2.7.2 Condition of stator and rotor cores (p. 14)
    • §3.1 Recording the winding details (p. 15)
    • §4 Rewinding: coil extensions, concentric and lap windings, Figures 23–24 (p. 20)

  4. SKF

    Bearing damage and failure analysis

    PUB BU/I3 14219/3 EN, June 2025. Link checked 17 October 2026.

    Sections used:

    • §1 Bearing life and bearing failures: causes of failure (p. 6)
    • Factors influencing bearing service life (p. 7)
    • Monitoring noise, vibration and temperature (p. 8)
    • Table 2, solution code 40: electrical erosion and contaminants (p. 28)
    • §5.4.2 Excessive current erosion (p. 41)

  5. ABB (Baldor-Reliance)

    MN416: AC & DC Motor Installation & Maintenance

    MN416, undated (issued after Baldor became part of ABB in 2018). Link checked 17 October 2026.

    Sections used:

    • Brushes (DC motors): periodic inspection and replacement (p. 2)

  6. WEG

    W22 Single-Phase Electric Motor: Commercial catalogue, European market

    Code 50069268, Rev 00, January 2017. Link checked 17 October 2026.

    Sections used:

    • Product overview: start and run capacitors, centrifugal-switch starting system (p. 2)

  7. Grundfos

    Pump Handbook

    Publication 96563258, 2004. Link checked 17 October 2026.

    Sections used:

    • §1.1.1 The centrifugal pump: liquid led to the impeller hub and flung outward (p. 8)
    • §1.1.4 End-suction, single-stage, multistage, long-coupled and close-coupled pumps (p. 12)
    • §1.1.6 Volute casings; return channels transform dynamic pressure into static pressure (p. 15)
    • §1.1.8–1.1.9 Multistage pumps; close-coupled constructions (p. 16)
    • §1.3–1.3.1 Mechanical shaft seals: components and function (pp. 28–29)

  8. Grundfos

    NB, NBG, MTB Installation and operating instructions

    96658389, 04.2021. Link checked 17 October 2026.

    Sections used:

    • §2.1 Product description: single-stage centrifugal volute pumps, axial inlet, radial outlet (p. 5)
    • §2.2.2 Type key: impeller diameter, pump housing, wear ring, shaft materials; single mechanical shaft seal (pp. 7–9)
    • §4.1 Mounting the motor: coupling guard, set screws in the shaft (p. 14)
    • §10.2–10.4 Shaft seal (no dry running), motor maintenance, motor bearing lubrication (p. 34)
    • §12 Fault finding (pp. 35–36)

  9. US Department of Energy

    Improving Motor and Drive System Performance: A Sourcebook for Industry

    Prepared by Lawrence Berkeley National Laboratory and Resource Dynamics Corporation. Link checked 17 October 2026.

    Sections used:

    • Synchronous speed = 120 × frequency ÷ number of poles (p. 6)
    • Glossary, "poles": pole count is set by the winding design

  10. Plant Engineering (article by Chuck Yung, EASA)

    Relationship of torque and shaft size

    13 April 2015. Link checked 17 October 2026.

    Sections used:

    • Torque = hp × 5,252 ÷ rpm: at the same power, a 900 rpm motor needs twice the torque of an 1,800 rpm motor

  11. ABB

    Process performance IE3 cast iron motors, frame sizes 280 to 355, generation L

    9AKK106128 EN 03-2014. Link checked 17 October 2026. Used only to show a tendency in one product range. Whole-motor weights, not copper weights.

    Sections used:

    • Technical data, 400 V 50 Hz: frame sizes and weights for 2-, 4- and 6-pole motors of 75–132 kW

  12. US Department of Energy

    Motor Systems Tip Sheet #11: Adjustable Speed Drive Part-Load Efficiency

    Tip sheet. Link checked 17 October 2026.

    Sections used:

    • A drive adjusts the frequency and voltage supplied to the motor

  13. Tsurumi Pump

    KTZ: General-purpose submersible dewatering pump

    Web page. Link checked 17 October 2026.

    Sections used:

    • Features: top discharge with side flow that cools the motor; high-chrome impeller; applications

  14. Tsurumi Pump

    Product technology: Oil Lifter

    Web page. Link checked 17 October 2026.

    Sections used:

    • Oil Lifter: role of the mechanical seal, oil film on the seal faces, how oil is lifted to the upper seal

  15. Tsurumi America

    KTZ/KTZE dewatering pump datasheet set (features KTZBL-P1, dimensions DM-KTZ-01, sectional parts SEC-KTZ-01, specification 60-SS-KTZ-01)

    Distributor-hosted copy (Pump World). Link checked 17 October 2026. The drawings in this PDF could not be measured; only its text and callout order were used.

    Sections used:

    • KTZBL-P1 features 2–4 and 6: seals in an oil chamber, air-filled motor, motor protector, top discharge
    • DM-KTZ-01: dimensions of the KTZ21.5-61 (648 mm high, 50 mm discharge, 35 kg)
    • SEC-KTZ-01: sectional parts list (items 1, 20–26, 30, 35, 50, 52A–56, 64, 68, 71)
    • 60-SS-KTZ-01 §1–5: sample specification (flow path, impeller and wear plate, seals, motor, cable entry)

  16. Tsurumi America

    KTZ/KTZE catalogue

    Distributor-hosted copy (Hardware City). Link checked 17 October 2026.

    Sections used:

    • Features: materials, two silicon carbide seals in the oil chamber, interchangeable impeller and wear plate

  17. Tsurumi Pump

    LB, HS, HSD, NK, LSC starting and operating instruction

    801-17200274-9 (distributor-hosted copy). Link checked 17 October 2026. Written for Tsurumi’s small dewatering pumps (LB/HS series), not specifically the KTZ.

    Sections used:

    • Maintenance, items (c)–(e): insulation check; seal-chamber oil replaced by a mechanic; milky oil or water drops mean repair is needed; motor opening left to a workshop

  18. Mining Report

    Tsurumi oil-chamber check (article)

    10 June 2021. Link checked 17 October 2026.

    Sections used:

    • Water or dirt visible in the oil indicates a leak, often at the mechanical seal

  19. Regal Rexnord (FASCO)

    Condenser Fan Motor, 1/2 HP, 1 Ph, 60 Hz, 208-230 V, 1075 RPM, 48 Frame, TEAO (D7907)

    Product page, regalrexnord.com. Link checked 17 October 2026. Used as one example of the representative design, not as an endorsement of a product.

    Sections used:

    • Key features: PSC, 10 µF 370 V capacitor required (not supplied with motor), thermally protected, totally enclosed air-over, class B insulation, ball bearing, 1/2" shaft with double flat, extended studs both ends, belly-band mount
    • Nameplate specifications; rain shield accessories

  20. Regal Rexnord

    Electric motor definitions

    Web page, regalrexnord.com. Link checked 17 October 2026.

    Sections used:

    • Air-over (AO): cooled by the air stream from the fan; end shield; thermal protector (automatic and manual reset); single-phase motor types including PSC

  21. Revcor

    Condenser Fan Blades (Riveted)

    Product page, revcor.com. Link checked 17 October 2026.

    Sections used:

    • Riveted construction; aluminium or coated-steel blades on a steel spider; 14" to 30" diameter; used in residential and commercial air-conditioning units

About this content

The explanations are summarised and simplified from the sources above for a general audience. They describe common designs and the usual ways they fail, not every motor. They give no lifetimes for parts, because lifetimes depend on design, duty, surroundings and maintenance. Each section of the Learning Center lists the documents, sections and pages it is based on. The PERS technical team has not yet reviewed this content. Where no manufacturer document has been matched, the single-phase and DC motor descriptions are marked as general.

Questions about a specific machine? Call +63 907 206 5092 or email proficient.ears@gmail.com.