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Hitachi Industrial Equipment Systems Co., Ltd.

Sufficient consideration is given to the safety and reliability, since it is used in a site using an explosive gas. The Hitachi explosion-proof hoist / crane saddle is designed for operation in a chemical or coating plant using explosive gas. The explosion-proof ability of the hoist / crane saddle is applicable to a range of gas up to Ignition group G4 and Explosion class 2. (Refer to the Table of Explosion and Ignition ratings for Explosive Gasses.)

  • The electric-system of Hitachi explosion–proof hoist / crane saddle is totally enclosed. Even if an explosive gas exploded within the container, the container withstands the pressure of such an explosion and the gas existing outside of the container is not ignited, guaranteeing the explosion proof of the hoist / crane saddle.
  • The explosion–proof ability of the hoist / crane saddle is determined by the stipulations of ether the “Explosion-proof Guideline for Electrical Equipment in Factories” or ”Explosion-proof Standard for Gases and Vapor” through the conditions vary by the ignition group and explosion class of the using gas and the place of its existence.
    Not only the motor, but the brake and terminal box are all given the explosion-proof treatment. (Product approved by the Ministry of labor in Japan)

Rope Hoist : Explosion-proof Type Hoist / Crane Saddle / structure

Standard Specifications

Hitachi explosion-proof hoist is designed so that it corresponds to the following regulation categories of Japanese Ministry of Labor.

Explosion-proof Construction d
Ignition Group G1 to G4
Explosion Proof 1 and 2
Division of Hazardous Locations 2

In order to operate the explosion-proof safely even in the places with an explosive gas, reasonable maintenances should be taken place as the explosion-proof construction must be kept effectively. Also, any building in which the explosion-proof hoist is installed should be equipped with a ventilation system so that the explosive gas is eliminated effectively.

The standard ambient conditions for the explosion-proof electrical equipment is as follows:

  • Altitude : Up to 1,000 m
  • Ambient temperature : -10 to 40 °C
  • Humidity : 45 to 85 %
  • Indoor application

Type of Explosion-Proof Hoist

The "– XX" in the types show the explosion-proof.


  • Explosion-proof Type 1 ton Hoist : 1M-T65-XX
  • Explosion-proof Type Suspension Type Crane Saddle : SL6-28-XX
    Following information should be indicated when quotation of the explosion-proof type is required.
    • Kind of gas
    • Concentration of gas
    • Ventilation conditions of the room where the gas exists
    • Working conditions including max. No. of starts per hour and duty factor
    • Traversing distance and if any curved travel is included
    • Other electrical equipment installed in the room and if they are explosion type or not.

Classification of Explosive Gases

Explosive gases are classified according to their ignition rating and explosive rating depending on the degree of danger.

1. Ignition Group

Ignition groups are classified as follows according to the ignition points of the individual gases. The Hitachi explosion-proof hoist can be used for gases of up to G4 for ignition groups or up to 135°C for ignition point.

Ignition Group Ignition Point
G1 Over 450°C
G2 Over 300°C to 450°C
G3 Over 200°C to 300°C
G4 Over 135°C to 200°C
G5 Over 100°C to 135°C
G6 Over 85°C to 100°C

2. Explosion Class

Explosion class is classified into the following depending on the value of the gap through witch the ignition spreads.

Explosion Class The value of the gap through which the ignition spreads with 25mm in depth.
1 Over 0.6 mm
2 Over 0.4 mm to 0.6mm
3 0.4 mm and below

3. Classification of Explosive Gases

Typical explosive gases classified by the ignition and the explosion ratings are as follows:

Explosion Class
G1 G2 G3 G4 G5 G6
1 Acetone
Carbon monoxide
Acetic acid
Ethyl acetate
Isomyl acetate
Acetic anhydride
Ethyl ether
  Ethyl nitrite
2 Coal gas Ethylene
Ethylene Oxide
3 Water gas
Acetylene     Carbon disulfide Ethyl nitrate

Bold text — Hitachi explosion-proof hoist can be operated.

4. Upper Limit of Temperature rise

The upper limit rise of temperature of electrical equipment in an explosive gas is as follows when the ambient temperature is 40°C.

Ignition Group G1 G2 G3 G4 G5 G6
Upper Limit of Temperature rise 320 200 120 70 40 30

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