Application, maintenance and upkeep guide for electric hoists in explosive environments

As a key lifting equipment in high-risk areas, the maintenance of the Explosion Proof Electric Hoist is directly related to safety production and equipment life. The following provides systematic technical guidance from the dimensions of application scenarios, daily maintenance, regular repairs, and fault handling.

1、 Application scenarios and security requirements

Typical application areas

Petrochemical industry (refinery, storage tank area)

Underground coal mine (roadway lifting, equipment installation)

Pharmaceutical/Military Industry (Handling of Flammable Raw Materials)

Dust environment (flour mill, wood processing)

Core safety standards

Explosion proof rating: Must comply with standards such as Ex d IIB T4 or Ex tD A21 IP65

Protection level: IP54 (dustproof and waterproof) or higher

Temperature group: T1-T6 (selected based on the self ignition point of the ambient gas)

2、 Key points of daily maintenance

Pre operation inspection

Appearance inspection:

The explosion-proof shell has no cracks or deformations, and the sealing components are intact

The cable is undamaged, and the joint is tightly filled with explosion-proof adhesive

Functional testing:

Sensitivity test of limit switch (3 times of no-load operation)

Brake clearance adjustment (≤ 0.7mm, brake pad thickness ≥ 3mm)

Monitoring during operation

Temperature monitoring:

Motor surface temperature ≤ 80 ℃ (using infrared thermometer)

Bearing temperature ≤ 65 ℃

Abnormal response:

Abnormal vibration (≥ 8mm/s requires shutdown)

Abnormal noise (>85dB needs to be investigated)

Post operation maintenance

Cleaning and maintenance:

Apply 204-1 anti rust oil to the explosion-proof surface (once every quarter)

Clean the oil stains on the guide rail (once a week)

Lubrication management:

Add 3 # lithium grease to the gearbox (replace every 2000 hours)

Apply wire rope grease to the steel wire rope (once a month)

3、 Regular maintenance plan

Technical requirements for maintenance cycle and maintenance items

Monthly electrical system inspection: grounding resistance ≤ 4 Ω, insulation resistance ≥ 1M Ω

Quarterly mechanical component wear detection: gear wear ≤ 15%, chain elongation ≤ 3%

Annual explosion-proof performance re inspection, explosion-proof joint surface gap ≤ 0.15mm

Replace all seals and repaint with anti rust paint after a 3-year overhaul of the entire machine

4、 Common fault handling

The motor cannot start

Possible reasons:

The circuit breaker inside the explosion-proof control box tripped

Power phase loss (detected using a multimeter)

Handling measures:

Check if the load exceeds the limit (within 80% of the rated load)

Reset the circuit breaker and test the insulation

Abnormal increase in speed

Possible reasons:

Brake not fully released (clearance too small)

Gear jamming of reducer

Handling measures:

Adjust the brake clearance to 0.5-0.7mm

Disassemble the reducer and clean the gear oil sludge

Explosion proof shell damaged

Urgent handling:

Immediately shut down and isolate the hazardous area

Use explosion-proof adhesive to temporarily seal the damaged area

Permanent repair:

Replace the explosion-proof casing with the same specifications (re certification required)

5、 Safety precautions

Personnel qualifications

Maintenance personnel must hold an explosion-proof electrical operation certificate (IC card)

Perform JSA (Job Safety Analysis) before operation

Tool Management

Only use copper or explosion-proof tools (such as copper hammers, explosion-proof wrenches)

Prohibit carrying non explosion proof electronic devices such as mobile phones into the work area

record management

Establish and maintain archives (including testing data and records of component replacement)

Retain the explosion-proof certificate and inspection report for at least 5 years

6、 Technical upgrade suggestions

Intelligent transformation

Install vibration sensors (to monitor bearing status)

Deploy wireless temperature monitoring system (real-time warning)

Energy efficiency optimization

Replace IE3 energy-efficient motor (saving 15% -20% energy)

Adopting frequency conversion control (reducing starting current surge)

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment