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Thread: Class II, Division 2 Groups F & G Motor with Variable Frequency Drive

  1. #1
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    Class II, Division 2 Groups F & G Motor with Variable Frequency Drive

    Can I use the following motor in a Class II, Division 2 Groups F & G environment with a Variable Frequency Drive if the Max Amb. temp on the motor is lower the the T-Code of the environment?
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  2. #2
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    One of the reasons we have various Hazardous "Classes" is that some concerns, such as a build-up of material on the enclosure surfaces in Classes II & III, don't generally occur in Class I.

    Unfortunately, even after blowing up the photo, I can't determine the enclosure Type nor the "T-Code". (This doesn't mean no one can, but my eyesight isn't what it used to be) I do note the nameplate indicates the motor is suitable for PWM inverters.

    Section 502.125(B) outlines the requirements for Class II, Division 2 motors. The Section and its Exception permits a fairly broad range of enclosure Types and a PWM rated motor will likely meet the temperature requirements of Section 500.8(D)(2). Other considerations, such as maintenance and housekeeping, may enter into the evaluation. In general, I'd say the odds are in your favor, but I can't say for sure without more details.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2017 NEC unless otherwise noted.

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