NEMA Frame Assignments - 3-Phase Induction Motors

The most widely used type of electric motor for driving a hydraulic pump is the 3-phase, squirrel cage induction motor, with Design B electrical characteristics. It is available in open drip-proof, totally enclosed, and explosion proof frames. Information in this issue is concerned with frame assignments and with the dimensions of shaft length, diameter, and height above base, which have to do with selection of a pump coupling, and with the height of a pump mounting bracket. Please refer to Design Data Sheets 3, 33, and 49 for other information on electric motors.

The shaft dimensions are in inches. They are listed with the open drip-proof motors, but apply also to the totally enclosed motors which have the same NEMA frame assignments.

POLYCARBONATE (PLASTIC) BOWLS FOR AIR LINE FILTERS & LUBRICATOR

Polycarbonate (plastic) bowls used on air line filters and lubricators represent a major safety hazard if not properly operated and maintained. We recommend that plastic bowls be protected with a bowl guard to confine fragments in case of bowl failure.

All plastic bowls on equipment you manufacture for resale (OEM) should be protected to avoid liability lawsuits in case of accident.

All manufacturers of this type of equipment obtain their raw plastic from one of two sources - General Electric Co., or Mobay Chemical Co. The plastic has been developed over many years to be the safest that it has been possible to produce, but no plastic is completely impervious to the action of chemicals, heat, and high pressure. This sheet gives a summary of important characteristics of the polycarbonate plastic from which the bowls are made.

Chemical Properties
It is resistant to water, organic and inorganic acids, mineral, animal, and vegetable oils, fats, and dilute acids.

It is attacked by strongly alkaline materials such as ammonia. See partial list of materials in the table.

It is partly soluble in chlorinated hydrocarbons, ketones, esters, benzene-toluene type chemicals and other materials.

It is highly soluble in many liquids such as acetone, gasoline, lacquer thinner and other materials in the table.

It has a tensile strength of 8,000 to 9,000 PSI, and so has a high impact resistance.

Materials Harmful to Polycarbonate Bowls
This is only a short list of the many chemicals which affect polycarbonate. For information on a specific chemical, contact General Electric Co. or Mobay Chemical Co.

Cautions
Do not use a plastic bowl where it will be subject to internal or ambient external temperatures higher than 120°F, or where air pressure exceeds 200 PSIG.

Do not use near, or do not clean with such materials as acetone, alcohol, benzene, dioxane, ethyl acetate, lacquer thinners, toluene, chloride, carbon tetrachloride, alkalies, amines, ketones, esters, aromatic hydrocarbons, or any other of the items listed in the chart.

Do not allow rags or other things containing substances that may be harmful to polycarbonate to lie under, on top of, or near a polycarbonate bowl.

Never paint a polycarbonate bowl.

Do not use on air which contains vapor or mist of a synthetic fire resistant fluid, nor on an air line served by a compressor which uses this fluid as a lubricant.

Suggestions
Inspect your plant and check your purchasing department and inventory list to detect the possible presence of materials which will attack polycarbonate plastic bowls and their location for storage and/or use in your plant.

Replace all polycarbonate bowls once a year unless they are protected by a metal bowl guard.

Purchase from the supplier of your plastic bowl equipment metal guards for all exposed bowls in your plant.

On all new equipment purchased, make sure the filters and lubricators are equipped either with metal bowls or with bowl guards.

For all lubricators, use only non-detergent petroleum oil of very low viscosity, equivalent to SAE 5 or SAE 10. Do not use or add anti-freeze compounds to the lube oil.

If bowls become dirty, clean only with a clean dry cloth.

© 1990 by Womack Machine Supply Co. This company assumes no liability for errors in data nor in safe and/or satisfactory operation of equipment designed from this information.