2. Our panelists Speakers: Moderator:
George Gulalo President MTT Technical Services
Bill Sutton Electrical Engineer Kollmorgen
Moderator:
Chuck Murray Senior Technology Editor Design News 2

3. Table of Contents Introduction Defining Wet Environments
The Breadth of Applications Where Water and Liquids Pose a Threat to Motors and Drives
What happens when water contaminates the electric motor environment?
What must we consider when faced with a wet environment?
Application with Examples: Challenges and Solutions
Presentation Summary
Extras:
Major Contributors to the Presentation
IP Ratings Table
NEMA Enclosure Standards
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4. Introduction
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5. what should you get out of this presentation?
An appreciation of the system design challenges when placing motion systems in wet environments. An understanding of the design guidelines and the different degrees of protection from water provided by two standards organizations; the IEC and NEMA What makes motors and drives susceptible to water damage. What can you do to protect the motors and drives from the wide range of water challenged applications.
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6. Defining wet environments
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7. Accepted Ingress Protection Ratings
Ratings defining protection from solids and liquids have been created by two well recognized organizations; the International Electro-Technical Commission (Worldwide) and NEMA (U.S.) The IEC was founded in 1906 as a not for profit, NGO with HQ in Switzerland. Member countries create national committees to participate. The U. S. is a full member.
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8. IP Ratings
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9. IP Rating System
The Ingress Protection (IP) rating system, published by the International Electro-technical Commission (IEC), that relates to proven protection against environmental factors such as liquids and solids. The format of the rating is: IP XY The first number (X) refers to the amount of protection a device has against solid matter (such as dust particles), while the second number (Y) defines the level of protection against liquids. The larger each digit is, the greater the protection The next slide depicts all of the liquid related IP ratings using ‘clip arts’ in place of words. Two tables, more fully describing the ratings, appear in the ‘Extras’ section of this presentation.
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11. nema standards
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12. NEMA Enclosure Standards
The National Electrical Manufacturing Association (NEMA) has also established standards for enclosures housing electrical equipment (< 1000 ac volts). A NEMA Type designation provides general guidelines for enclosures based on their ability to protect the enclosed electrical/electronic components from harmful effects of the ingress of certain solids and liquids. The next set of slides provides you my summary of the standards from NEMA in convenient table format. A more detailed version appears in the ‘Extras’ section of this presentation.
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13. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
1 (indoor)
falling dirt
No protection.
Degree of protection to people against access to hazardous parts
2 (indoor)
dripping and light splashing
3 (in/out)
falling dirt and windblown dust
rain, sleet, snow, ice on outside
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14. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
3R (in/out)
falling dirt
rain, sleet, snow, ice on outside
Degree of protection to people against access to hazardous parts
3S (in/out)
rain, sleet, snow, external mechanism operable when ice laden
3X (in/out)
falling dirt and windblown dust
rain, sleet, snow, resists corrosion from external ice formation.
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15. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
3RX (in/out)
falling dirt
rain, sleet, snow, undamaged by ice, resists corrosion from external ice formation.
Degree of protection to people against access to hazardous parts
3SX (in/out)
falling dirt and windblown dust
rain, sleet, snow, external mechanism operable when ice laden, resists corrosion from external ice formation.
4 (in/out)
rain, sleet, snow, splashing water and hose directed water, damage from external ice formation.
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16. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
4X (in/out)
windblown dust
rain, sleet, snow, splashing water and hose directed water, resists corrosion and will be undamaged from external ice formation.
Degree of protection to people against access to hazardous parts
5(indoor)
falling dirt and settling airborne dust, lint, fibers, and flyings
dripping and light splashing
6 (in/out)
falling dirt
hose directed water and the entry of water during occasional temporary submersion at a limited depth and will be undamaged from external ice formation.
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17. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
6P (in/out)
falling dirt
hose directed water and the entry of water during prolonged submersion at a limited depth and resists corrosion and will be undamaged from external ice formation
Degree of protection to people against access to hazardous parts
12 (indoor)
falling dirt and circulating dust, lint, fibers, and flyings
dripping and light splashing
Enclosures constructed (without knockouts) offering a degree of protection to people against access to hazardous parts
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18. Offer a degree of protection against ingress of…
NEMA
NEMA Enclosure Type
Solids
Liquids
Other Purposes/ Conditions
12K (indoor)
falling dirt and circulating dust, lint, fibers, and flyings
dripping and light splashing
Enclosures constructed (with knockouts) offering a degree of protection to people against access to hazardous parts
13 (indoor)
Dripping, light splashing and spraying, splashing, and seepage of oil and non-corrosive coolants.
Degree of protection to people against access to hazardous parts
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19. Comparing NEMA and IP enclosure ratings
There is no exact way to match IP Ratings with NEMA Enclosure types. NEMA has more criteria associated with their enclosure types than the IEC.
In particular NEMA also takes in to account product features not addressed by IP codes such as:
construction practices
corrosion resistance
protection for people
impact of ice
gasket aging
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20. Comparing NEMA and IP enclosure ratings
This following comparison table is only approximate. Each application needs to be individually evaluated and it is recommended that the user verify the enclosure rating necessary.
Source:
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21. breadth of applications
With significant contributions from Rick Halstead, Empire Magnetics
breadth of applications
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22. Breadth of Applications: Introduction
The following slides list applications where water proofing a motor may be necessary. The number and breadth of applications is quite large.
The list would be larger if we included all applications where water presents a potential danger to motors and drives.
We will leave discussing applications later on in this presentation where we will focus on a few interesting examples.
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23. Selected Water Challenged Applications Undersea Exploration and Military
Automated undersea lights and cameras Naval/military Robotic submarines Salvage robots Undersea oil and mining exploration Undersea oil and mining extraction
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24. Selected Water Challenged Applications Sea Surface
Automated hydrophone arrays Aquaculture Floating seafood factories Hydrofoil air cushion controls Sonar arrays Wave power generation
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25. Selected Water Challenged Applications On and Above Land, Large Scale Activities
Automated inspection: Water jets and ultrasound in water tanks, inspection of nuclear reactor components Flood control systems Mining Oil exploration and drilling Pipeline welding and pipeline x-ray equipment. Railroad track grinding equipment Toxic clean-up equipment Upper atmosphere wind study equipment
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26. Selected Water Challenged Applications Food Production (Manufacturing)
Automated ice cream cup fillers Corn dog machines Food packaging, dispensing, vacuum sealing, inspecting and labeling Food processing cleaning, chopping, etc. Juice box filling and sealing machines Meat slicers Pineapple coring machines
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27. Selected Water Challenged Applications Other Manufacturing
Automated machine tools: Mills, lathes, screw machines, grinding applications, cut-off tools Chemical manufacturing Drug manufacturing: Pill pack sealing, packing, labeling, gene splicing microscope stages, media plate filling Medical supply manufacturing: Artificial blood vessels, rubber gloves, sterile bandages Paper manufacturing
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28. Selected Water Challenged Applications Communication Systems
Antenna and gun pointing systems Communications in Hostile Environments Systems for satellite tracking stations
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29. Selected Water Challenged Applications Other Segments
Processing of Metals and Films Large Scale Printing Water jet cutting in production settings Sterilization of motorized medical and dental instruments
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30. effect of water contamination
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31. introduction
We can all imagine what damage can be caused by water in a motor but aren’t motor winding conductors, laminations and housings already coated to protect them from external contamination? Not always. Not completely. Not really. Let’s explore what makes motors and motor and drive housings vulnerable to water.
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32. Motor Characteristics That Make Them Vulnerable to Wet Applications
Electrical Conduction Through Water in Insulation Flaws
The magnet wire of the coils, a solid copper wire is coated with an enamel or varnish and covered by an insulation. However, small pin holes are almost always present.
But pin holes rarely line up so shorts between coils is rare. But when a little water gets in to the windings, it can provide a conductive path between unaligned pin holes and insulation flaws. With voltage applied the current from the power supply can quickly destroy the motor windings.
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33. Motor Characteristics That Make Them Vulnerable to Wet Applications
Electrical Conduction Through Water in Insulation Flaws
And impregnation does provide better electrical insulation (and prevents vibration in the motor windings). Impregnation can also increase the thermal conductivity and reduce water absorption to reach a better environmental balance.
Although quality insulation and impregnation can reduce if not prevent this problem, they add greatly to product cost.
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34. Motor Characteristics That Make Them Vulnerable to Wet Applications
Rust in the Stator Laminations
The magnetic iron in motors tends to corrode very easily when subjected to moisture.
Mechanical tolerances between the rotating part of the motor and the stator iron are small to optimize motor torque. In some motors such as step motors, air gap tolerances are often held to about .002 in.
When the motor is operating, these teeth get hot, and the temperature is typically high enough to turn any water in the motor into steam. Steam is corrosive, such that the magnetic iron in the teeth rusts faster than usual.
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35. Motor Characteristics That Make Them Vulnerable to Wet Applications
Bearing degradation with iron rust.
Accumulation of rust on the iron parts grows and in small air gaps, rotor and stator teeth can begin to rub.
The rust particles combine with any water intruding in to the motor and form an abrasive slurry (sludge). This oxide slurry gets into the motor bearings, and bearing wear accelerates.
Worn bearings cause the motor to wobble and additional rubbing occurs.
The combination of oxide build-up on the magnetic teeth and the loss of bearing accuracy can cause a standard motor to fail in a period as short as two weeks when water gets inside.
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36. Water Damage to Windshield Wiper Motor
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A sludge of water, rust, and
oil coated the water logged
motor.
Water finds pin-hole
flaws shorting through
the winding insulation
causing excessive heating
even burning.
Source: wiper_motor_replacement.htm
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37. Salt Water Damage to Tesla Model S Electronics
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Salt Water Damage to Tesla Model S Electronics
A low lying coastal area
was inundated with sea water
flooding up to seat level
a Tesla Model S.
Source: wiper_motor_replacement.htm
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38. what must we consider when faced with a wet environment
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39. what to consider in a wet environment
When thinking of protecting a motor from threats from water and other liquids it is natural to think first of a suitable housing. But there is a lot more to assuring your motor or drive is safe from the surrounding wet environment. Here are some of the items you need to consider:
Motor and Drive External Housing
Wire/Cable entering and exiting the housing
Connectors
Shafts
Motor winding insulation
Internal Motor Volume- Potted? Liquid Filled? Pressure equalized?
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40. what to consider: in a wet environment-more
And it is not unusual that the threat to the motor and drive is only from liquids. Many wet environment applications also include other challenging environmental characteristics: High heat High pressure Radiation Let’s not forget that applications such as food production themselves must be protected from motor liquids such as bearing greases and other lubrications. While we will focus on the impact of liquids keep in mind the environment in its totality must be considered.
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41. What are some of the solutions?
protection from water
What are some of the solutions?
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42. Water Proofing Motors/drives
Make externally exposed materials (housing, end bells, shafts) out of corrosive resistant metals.
Standard motor and drive housings are made of painted cold rolled steel and/or aluminum, a waterproof motor's exterior is commonly made of stainless steel to resist corrosion.
Different steel alloys are employed depending on the corrosive threat.
Stainless steel alloys with varying nickel chromium content are used for underwater and in other environments where ordinary motors are unsuitable.
Alloys ranging from 303 stainless for ordinary submerged applications, to 316 stainless for exposure to caustic or marine environments.
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43. Water Proofing Motors/drives
More approaches to wet environments:
Fit the motor to accept redundant shaft seals. Water proof motor’s shaft itself is provided with redundant shaft seals.
Fit the motor to accept O rings.
A waterproof motor is designed to accommodate O-ring seals, allowing the watertight sealing that is not practical in a standard motor
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44. Water Proofing Motors/drives
More approaches to wet environments:
Employ hermetic cable feed-throughs for motor and drive.
The wiring that leads to the motor coils in a waterproof motor requires a hermetically-sealed feed-through device to prevent water from wicking into the motor via the cable conductors.
Pressure equalization techniques
bleeder tubes
oil filled
adjustable bladders
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45. Water Proofing Motors/drives
Consider sealants for bolts, bolt holes, end bells and shaft outs
Other Seals to Consider
A threaded pipe plug at the rear of the motor is designed to allow the housing to be sealed after the motor connections have been made; this plug is also fitted with an O-ring seal.
Modifications to components such as:
brush cards for dc motors
commutator and sensor circuitry for brushless motors
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46. Water Proofing Motors/drives
Additional life-extending features include: double insulation coated laminations fittings for pressurization
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47. water proofing summary
Protecting motors and drives from a wet environment must consider the complete environment around the motion components: Water pressure Water temperature Water corrosiveness salt water cleaning solutions other Temperature and pressure changes Other threats such as radiation And lets not forget protecting the environment from the motor; motor fluids and motor self generated particulate contaminants.
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48. application examples
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49. FEATURED APPLICATIONS
Food production
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50. Food Production Example: Motor and Gearbox Failure
Standard Servo Motors and Food Grade Motors fail in as little as 4 weeks in wash-down areas. Stainless Steel motors deemed wash-down in as little as 6 months
Failure Modes
Ingress of moisture and cleaning agents into
bearings, windings, and feedback
Cable jackets degrade due to chemical reaction
and high pressure wash
Connectors fail due to improper specification
Example courtesy of Kollmorgen

51. Food Production Example: SOLUTION TO Motor and Gearbox Failure
316L Stainless Steel
Durable cable Jacket (2-12pH, 1450 PSI)
Vented Cable – Pressure Equalization
One Cable
No connectors or if needed IP69K
Easier to clean – adds to durability
2 Year Warranty Against Ingress
Example courtesy of Kollmorgen
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52. Food Processing Motors and Cleanability
Gearboxes
Motors
Pneumatic
Components
HMIs
Sensors
Belts
Conveyors
Hydraulic
Q33: Rate each of these machine components on ease of cleaning
79% said motors are a problem to clean
Q34: How concerned are you that these peripheral components listed in question 33 are possible sources of pathogenic contamination?
95% at least somewhat concerned
Nook, crannies, external hardware, rough surfaces, cables, nameplates

53. Hygienic components
Design purchased components to be “cleanable” just as important as functionality for overall hygienic machinery design

54. Engineering in Customer value
How did we get from this…
AKM Servo
…to this?
AKMH Servo
100+ end user visits globally
Durable enough to be cleaned – 2-12pH, 1450 psi spray
Smooth 32µ surface finish, including nameplate
No external hardware
No metal to metal seams
No nooks and crannies
One cable rather than two

55. submerged cutting tool for nuclear fuel rods for US submarines
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56. Submerged nuclear fuel rod saw
Motor and gearbox submerged in 30 feet of water for life. Stainless Steel 316 Placed in de-ionized water and became toxically contaminated with radiation and could never be handled by people or removed from the water. Seals had to be water proof and radiation hardened. Special cables. Perhaps one of the most expensive motor/gearbox devices ever built.
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57. Submerged nuclear fuel rod saw
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58. Submerged nuclear fuel rod saw
Handles- Robotic Lifters
Stainless
Steel
316
Motor
Gearbox
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59. Application Example: Deep Sea
Challenges-Problems-Solution
Application Example: Deep Sea
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60. Deep Sea Application
Deep sea is a forbidding place in which to launch a motion control application. Very cold temperatures, the corrosive effects of sea water and extremely high pressures (as much as 5,000 p.s.i. at 11,600 feet below the surface) combine to create an environment in which off-the-shelf components will quickly fail.
Example courtesy of Empire Magnetics
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61. reserved for pictures
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62. Deep Sea Challenges
You must prevent water entry to the motor Assure that motor materials are resistant to corrosion Make allowances for material shrinkage (O-rings and other elastomeric materials compress in the depths) Prevent water entry into electrical cables Account for power losses that occur over the 1,000+ ft. umbilical cable from the ship. Choose a filling oil whose thermal properties assure it is still a liquid at high pressures and low temperatures.
Example courtesy of Empire Magnetics
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63. presentation summary
Water, electric motors and drive electronics just don’t mix. Successfully implementing a motion solution in a challenging wet environment requires a full review of all aspects of the application. Standard protection ratings are available but only as a guideline. Each application needs to be carefully understood with solutions that match conditions. Truly water proofed motors and drives most likely will require some custom aspect to the system.
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