Motor Specification Question 2

[jdkuhndog]

In a specification I am reviewing, under the Motor section there were two requirements which I don't fully comprehend...

1) Protection shall be provided against galvanic action between dissimilar metals by the use of gaskets, washers or other appropriate means.

As far as I know, there are no dissimilar metals within a motor which make contact with one another. Is this true? This is not even a corrosive environment where this will be operating - so I am not sure why it was included in the spec.


2) Non-metallic material shall be fire resistant, anti-static, and stable in the presence of hydrocarbon liquid, vapor and gas.

What non-metallic material do they expect to encounter in a motor? terminal blocks and insulation...anything else? just seems like a strange requirement...has anyone run across this before?

Thanks in advance.

 

[CanEngJohn]

In response to item 1 they are talking about chemical reactions that occur (for example) when aluminum and steel interact.

Item 2 - typical non-metallic materials would include gaskets and paint.

 

[CanEngJohn]

Oh and I forgot. There is nothing abnormal about these requirements. They are very basic motor requirements across industry. However, some contries are just starting to implement them other countries have been that way for years.

 

[MintJulep]

To clarify CEJ's first post, the end bells and the body might be different metals.

Other non-metallic parts might include shaft seals, and if it is a fan-cooled motor, the fan.

 

[jdkuhndog]

Thanks for the responses...I didn't even think of the aluminum housing !!

Would a standard motor already have gaskets between the housing and the body?

Would a standard motor have non-metallic parts which met the criteria mentioned?

 

[MintJulep]

There is no such thing as a standard (with a little s) motor.

There are motors that are build to meet a given Standard (with a capital S). There are many motor standards in existance. NEMA MG-1, IEC, IEEE, and on and on.

If you go to a cheepee motor supplier, you quite probably can buy a motor made to no standard at all. The supplier would probably gladly tell you that he is selling you a "standard motor".

Pass your customer spec requirements, along with your own application specific requirement on to a reputable motor manufacturer and ask for their best recommendation. Then get every bit of literature and test data available. If test data is not available, insist that the manufacture perform the appropriate test. Then read and understand all of that information. You will find things that you don't understand. Ask direct and pointed questions to the manufacturer. Eventually you will both come to the conclusion that the origianlly proposed motor is not adequate for the application. Repeat until you have something that will work for you.

 

[jsummerfield]

If the motor will be used in an area classified Class I, Division 2 with the potential for trhe presence of hydrocarbon liquid, vapor and gas, consider looking into motors rated IEEE Std 841-2001. This is the IEEE Standard for Petroleum and Chemical Industry—Severe Duty Totally Enclosed Fan-Cooled (TEFC) Squirrel Cage Induction Motors— Up to and including 370 kW (500 hp).

John