1. Purpose and scope

This guide is intended for the maintenance of electric cranes, in particular for checking the gearbox, brake disc and measuring the chain tension. The technician should perform this maintenance regularly, according to the manufacturer's recommendations, to ensure the safety, stability and longevity of the equipment. The craftsman should perform these actions before starting work, after resuming the production process, or when detecting unusual noises, vibrations or an increase in temperature.

2. Security

Important: Before starting any work with the electric crane, complete the Lockout/Tagout procedure of all energy sources. Use protective clothing, gloves, goggles and protective gloves. Do not perform work in the presence of electrical energy or under pressure.

3. Necessary tools and materials

Tool	Specification	Quantity
Torque wrench	0–100 Nm, with markings	1
Multimeter	0–500 V, 0–20 MΩ	1
A ruler with a scale of 0–300 mm	Metric	1
Micrometer	0–25 mm	1
Laser for measuring centration	Accuracy ±0.02 mm	1
Pencil and iron end	For cleaning	1
Protective gloves	Reactive, thermally stable	1 pair

4. Before service: Inspection

Item	Verification	Acceptance/rejection criteria	Notes
1	Make sure the electric faucet is turned off and unplugged	Lack of electricity	Apply the Lockout/Tagout procedure
2	Check the absence of pressure in the hydraulic system	The pressure in the system is no more than 0.5 bar	Apply the shutdown procedure
3	Check for slag or dust	No slag on the surface	Use the iron end
4	Check for moisture	The ambient temperature is at least 5 °C	Use a thermometer
5	Check the absence of defects in the chain	No stretching, tearing or damage	Use a ruler

5. Passport procedure

Opening the gearbox: Open the top of the gearbox using a special size wrench. Measure the clearance between the gears with a micrometer. The gap should not exceed 0.1 mm.

Error: Do not use rough tools to avoid damaging the gears.
Measuring the brake disc: Use a ruler with a 0-300mm scale to measure the thickness of the brake disc. The thickness should be at least 15 mm. If the thickness is less, replace it.

Error: Do not use discs smaller than 15 mm, it may cause explosion.
Measuring Chain Stretch: Measure the length of the chain from start to finish. The elongation should not exceed 5% of the nominal length. If the stretch is more than 5%, replace the chain.

Error: Don't use chains with more than 5% stretch, it can cause explosion.
Cleaning: Use the iron tip to clean the inside of the gearbox. Use a micrometer to check clearance.

Error: Do not use rough tools to avoid damaging the parts.
Oil change: Replace the oil in the gearbox with a new one of the appropriate viscosity (ISO 46). Use an oil pump to drain the old oil.

Error: Do not use oil with viscosity other than ISO 46, it may cause explosion.
Bolt tightening: Tighten the gearbox bolts using a torque wrench with a range of 0-100 Nm. The bolts should be tightened to 50 Nm for the bolts that fix the gears and 30 Nm for the bolts that fix the housing.

Error: Do not use improperly tightened bolts, it may cause explosion.
Checking the brake: Use a multimeter to check electrical resistance. The resistance should be 0.5 MΩ. If the resistance is less, replace it.

Error: Do not use brakes with a resistance of less than 0.5 MΩ, it may cause an explosion.
Recovery: Perform a hardware recovery using the laser to measure the centration. Centering should not exceed 0.02 mm.

Error: Do not use equipment with eccentricity greater than 0.02mm, it may cause explosion.

6. After service: Inspection

Test	Expected result	Actual result	Pass/Fail
1	The gap between the gears	No more than 0.1 mm	Pass/Fail
2	Brake disc thickness	Not less than 15 mm	Pass/Fail
3	Stretching the chain	No more than 5%	Pass/Fail
4	Tightening the bolts	50 Nm (gears), 30 Nm (body)	Pass/Fail
5	Electrical resistance of the brake	0.5 MΩ	Pass/Fail

7. Technical assistance

Symptom	Probable cause	Recovery
The electric faucet does not work	There is no electricity	Perform the Lockout/Tagout procedure and check the wiring
Unusual noises	Insufficient gap between gears	Measure clearance and recovery
Vibrations	Centering	Perform centering and recovery measurements
explosion	The thickness of the brake disc is insufficient	Replace the disk
Increased temperature	Insufficient clearance or oil leakage	Measure the gap and change the oil

8. Recommended maintenance schedule

Task	Frequency	Estimated time	Skill level
Checking the gearbox	Monthly	1 hour	Average
Measuring the brake disc	Monthly	1 hour	Average
Measurement of chain tension	Monthly	1 hour	Average
Oil change	Annually	2 hours	Tall
Brake recovery	Annually	2 hours	Tall

9. Indication of spare parts

Part description	Typical specification	UNITEC-D category
Gearbox oil	ISO 46, 10 l	Lubricating fluids
Brake disc	Material: cast iron, thickness: 15 mm	Brake components
Chain	Length: 1000 mm, turn: 15 mm	Chains
Bolts for the gearbox	Material: steel, length: 50 mm	Bolts and nuts
A pencil	Material: steel, length: 100 mm	Protective ends

For spare parts, visit our e-catalog: https://www.unitecd.com/e-catalog/

10. Reference books

- DSTU 2481: Technical requirements for electric cranes - EN 12615: Technical requirements for electric cranes - ISO 3454: Technical requirements for gearboxes - CE, UkrSEPRO certifications