Class I, Group B, Division 1 Hazardous Locations Motors

These electric motors are constructed to the requirements of U.L. Class I, Group D, Division 1. They are then modified to accept purge fittings on the motor and terminal box. In addition to the purged motor fittings, it is also supplied with a Bebco “Type X” purging system. This can be mounted on the motor, or wall mounted within 5 feet of the motor. The size of the motor is limited by the area to be purged. The motor and terminal box gaseous area combined must be less than 2 cubic feet.

The Bebco type “X” pressurization or purging system operates on a supply of compressed instrument air or inert gas. It is designed to regulate and monitor the pressure within the motor and terminal box in order to remove and prevent flammable vapor or gas accumulation. In Class I areas, the system is designed to accomplish ten air exchanges and maintain a safe (0.25”) pressure inside the motor enclosure. In addition the system includes and electrical power control unit (EPCU) that monitors system operation and controls motor power. All start-up requirements must be satisfied before the (ECPU) will allow power to the motor. These processes reduce the Hazardous (Classified) Area Rating within the motor and terminal box, in accordance with the NEC - NFPA 70, Article 500, NFPA 496 and ISA ds12.4.

In accordance with detailed instructions on the system, start - up requires the air supply to be engaged and ECPU power to be energized. In Class I Areas, the system must perform an exchange cycle (determined by the safe pressure flow rate - five minutes minimum) before power can be applied. Loss of safe pressure causes the ECPU to shut power down to the motor. All systems include form “C” contacts for audible or visual alarm systems.

Dietz supplies the motor and type”X” purging system as a complete unit. The motor has stainless steel nameplates indicating the system is suitable for operation in Class I, Group B, Division 1 hazardous areas. Additional stainless steel nameplates are also attached to the motor explaining the operation and warnings associated with purged electric motors for use in hazardous areas.

These motors are available in many mounting configurations. Please contact one of our engineers to get details on specific applications, and your requirements.

North American Standards
Explosion Proof Motors for Operation in
Class 1 Group B Division 1 Locations

Electrical equipment for use in class 1 hazardous (classified) locations, as defined in the National Electric Code, is tested with respect to acceptability of the operation in the presence of flammable and explosive mixtures of specific vapors and gases with air. For purposes of  area classification , such mixtures have been grouped on the basis of their characteristics as follows:

      Class 1, Group B: Atmospheres such as hydrogen (or gases or vapors equivalent in hazard to hydrogen gas), acolein (inhibited), butadiene, ethylene oxide, or propylene oxide.

The National Fire Protection Association (NFPA) determine safe practices and establish standards for all areas of commercial, industrial and residential construction. They publish many documents including NFPA code 70 – better known as the National Electric Code, and NFPA 496 – the document that outlines the practices for purging the motors and controls that Dietz offers.

NATIONAL ELECTRIC CODE 501-8 MOTORS AND GENERATORS

1. Class 1, Division 1. In Class 1 Division 1 locations, motors, generators and other  rotating electrical machinery shall be:

                  (1)  Approved for Class 1, Division 1 locations.
Note: (Approval authorities such as Underwriters Laboratories, and Factory Mutual Research do not offer standards on Class 1, Group B, Division 1, electric motors.

(2) Of the totally enclosed type motors supplied with positive pressure ventilation from a source of clean air with discharge to a safe area so arranged to prevent energizing of the machine until ventilation has been established and the enclosure has been purged with at least 10 volumes of air and also arranged to automatically de-energize the equipment when the air supply fails.

Totally enclosed motors of Type (2) shall have no external surface with an operating temperature in degrees Celsius in excess of 80 percent of the ignition temperature of the gas or vapor involved. Appropriate devices shall be provided to detect and automatically increase in temperature of the motor beyond designed limits. Auxiliary equipment shall be of a type approved for the location in which it is installed.

The motors offered by DIETZ ELECTRIC Co., INC. are Type (2) motors constructed to the requirements of Class 1, Group D, Division 1. They are then modified to accept purge fittings, supplied as a complete assembly with a purging system which complies with:
NFPA Code 496 Type “X” which reduces the classification within the enclosure from Division 1, to non-hazardous.

Acceptance of our system is subject to approval by the authority having jurisdiction at the installation.

Contact us for more information regarding Class 1, Group B Division 1 Motors. Request a quote today to order one or our purged motors. Also, see our Custom Division 2 Motors.