1). What is operation environment required for winch or hoist?

Ambient temperature : -20°C to +40°C

Ambient humidity : 85 % or less (no condensation)

Explosion-proof construction: Not applicable to the work environment with explosive gases or explosive vapor

Environment to be avoided:1. A place with organic solvent or volatile powder

2. A place with a plenty of powder and dust of general substances

3.. A place with considerable amount of acids and salts

Shelter required: When installing hoist or winch outdoors or to the place where the hoist is exposed to direct rain, wind and snow, shelter the hoist under a roof to protect it from rain, wind and snow

2). What kind of precautions should be paid at the time of operation of hoist or winch?

1. The operator of winch is required for qualifications according to applicable laws and ordinances.

2. Prior to starting of use, carry out the daily checking and use after confirming the safety of function

3. Don’t use exceeding the rated rope tensile force.

4. The operator of winch must not be apart from the operating position under the loading condition.

5. In order to prevent the layer down due to over loosening of rope, irregular winding, etc., operate according to the suitable operating method.

6. Wire rope must remain by 5 winding on the drum

3). What are the difference between ratings for winch in lifting or pulling applications?

As a general guide, increasing the drum core diameter will increase line speed with a proportionately equal decrease in line pull. The first layer of wire rope on the drum delivers the slowest speed and the maximum line pull, but a full drum delivers the maximum speed and minimum line pull.

Therefore, the ratings for electric winch is rated at the top layer of wire rope, but for the hydraulic planetary gear is rated at the first layer of wire rope.

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4). What are the ratings among lifting, pulling and rolling ?

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Pulling application: P = μ x W

Rolling application: P =μ x W + θ x W

The pulling force is calculated from the mass of the load to be load multiplied by the surface friction factor and gradient resistance.

 

The rolling resistance is around 0.15 for rubber wheels on the concrete surface and around 0.01 for a cart with steel wheels on the steel tracks.

Example of rolling forces

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5). How to determining required horsepower?  

One theoretical horsepower is equivalent to 33,000 lbs being lifted one foot in one minute. This equation does not account any of the inefficiencies inherent in motors, gear reductions, bearings or rigging.

Horsepower required > (Line pull (lb) x Line Speed)/33,000 ft-lb

 

6). What is the relation between line pull and line speed without changing horsepower?

To increase line speed without changing horsepower, the line pull shall be decreased accordingly.

To increase line pull without changing horsepower, the line pull

Shall be decreased accordingly.

7). Why is the importance of fleet angle

In order to promote proper spooling of the wire rope it is recommended a fleet angle 1 1/2° for smooth drums and 2° for grooved drums to be maintained. Exceeding these recommendations may cause poor spooling from rope piling up, and possible damage to the wire rope through crushing and abrasion.

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θ= 1.5° on smooth drum

   α= 2.0° on grooved drum

Minimum distance between the centers of winch drum and sheave

When θ= 1.5 approximately 19 times drum width in meter

     α= 2.0° approximately 15 times drum width in meter

 

8). Why is the D/d ratio so important?

   Wire rope fatigue and irregular wear caused by using a smaller than

recommended D/d ratio. For this reason “THAC” winch conform to EN

14492-1 standards which recommends a minimum of 15:1 (D/d) ratio for lifting and lowering applications and 10:1 (D/d) ratio for pulling applications.

 

9). How do you calculate the D/d ration

   D: first layer of rope pitch dia.

   D0: Drum barrel dia.

   d: Rope dia.

D/d ratio = (D0 + d)/d

 

10). Why is the wire rope safety factory so important?

Wire rope fatigue and irregular wear caused by using a unsuitable rope in construction, strength or having any defects. 

 

11). How do you calculate the rope safety factory?

Rope safety factory = Rope breaking strength (kg) / Winch or Hoist Rating

For this reason “THAC” winch conform to EN 14492-1 standards which recommends a minimum of 5:1 wire rope safety factory for lifting and lowering applications or 2:1 for pulling applications.

 

12). Why is the important of freeboard?

According to EN 14492-1 (Power Driven Winches), it required a minimum of 1.5 times wire rope diameter of freeboard be maintained However, to comply with SAE J 706 rating of winch, it required a minimum of 0.7 times. 

Freeboard is the amount of space from the top layer of the wire rope to the outside of the drum flange.

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13). What is duty cycle?

   The duty factor of the motor is a percentage of the total load operating time and the total load operating time plus the total resting time. Calculate the percentage duty cycle according to the follow formula.

Duty Factor (%ED) = Tb/(Tb+Ts)  x 100 (%)

Where,  Tb: Total load operating time  Ts: Total resting time

        Tb + Ts = Approximately 1 to 10 minutes should be set

 

14). What is the classification of hoist or winch?

    Explanation to drive FEM 9,511 (DIN 15020, ISO 4301) for rope drives

    Calculated operating times according to FEM 9,755

Load Spectrum

 Average daily operating time (hours/day)

 

Light

t≦2

2<t≦4

4<t≦8

8<t≦16

16<t≦24

Medium

t≦1

1<t≦2

2<t≦4

4<t≦8

8<t≦16

Heavy

t≦0.5

0.5<t≦1

1<t≦2

2<t≦4

4<t≦8

Severe

t≦0.25

0.25<t≦0.5

0.5<t≦1

1<t≦2

2<t≦4

 Duty Factor

25% ED

30% ED

40% ED

50% ED

60% ED

Driven

Group

ISO

M3

M4

M5

M6

M7

FEM

1 Bm

1 Am

2 m

3 m

4 m

Max. Start/hour

150≦

180≦

240≦

300≦

300≦

    Light:      Predominantly low loads                  

    Medium:   Frequently full loaded, however continuously lightly loaded

    Medium:   Frequently full loaded, however continuously medium loaded

    Extra-heavy: Regularly fully loaded

 

15). What is the Drum Configurations

In general speaking, there are find kinds of drum configurations for electric winch.

1. Winch with Plain drum 

     This is the most commonly used configuration. The rope is anchored

at the drum and travels  the barrel. 

2. Winch with Extended drum (fig1) 

     The winch with extended drum to suit a wide variety of application 

3.  Winch with Grooved drum (fig 2) 

      Parallel grooving evenly distributes the load between and show to

increases the life of the wire rope. Reduction of rope damage

benefits the safety operation.  

4.  Winch with two ropes in opposite winding (fig 3) 

       It can be used as a traversing winch to move a carriage forwards

and backwards in two direction on a level. The drum Is grooved for

one rope, with a second rope fastening attachment on the drum. 

5.  Winch with several ropes (fig 4)               

            The winch is grooved for two or several ropes with additional wire

rope fastening  attachment. Rope pays in and out together.

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16). How to decide a ratings of hydraulic planetary wnch is need in inch?

There are three factors result in a vehicle resistance.

1. Total Weight: A vehicle totol weight including personnel and all load

2. Gradient Resistance: The incline of grade on which the vehilce is being

Moved

3. surface Drag: The surface to be traversed

 

Gradient Resistance

Surface Drag (S)

Gradient

%

Angle (ref)

Gradient Value

Surface Type

Surface Value

2%

0.02

Hard flat road

0.04

5%

0.06

Grass

0.14

10%

0.11

Hard wet sand

0.17

20%

11°

0.19

Soft sand

0.20

30%

17°

0.30

Shallow mud

0.25

50%

26°

0.44

Shallow mud

0.50

70%

35°

0.58

Marsh

0.50

100%

45°

0.71

Clay

0.50

 

Gradient = Height/Distance

 A Gradient of 20% is a rise of one meter in tne meters distance.

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17). What kind of advantages of using snatch blocks?

     Use a snatch block for double line operation to increase line pull twice 

     as much as the line pull of the winch.

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    Figure1 shows the vehicle becomes the load,

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    Figure 2 show a direct pull on a load. The end of the wire rope may be 

    anchored directly to the vehicle.

18). What kind of purpose of Rope Tensioner is ?

     The purpose of rope tensioner is to keep the wire rope tight on the drum  

     while the winch is in freespool mode or while there is no load on the wire

     rope. However, the rope tensioner should not be relied to ensure the

     wire rope to be wound to the drum even


19). What is the relative ratio between oil flow and speed for hydraulic planetary winch?

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20). What is the relative ratio between working pressure and pulling rating for hydraulic planetary winch?

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21). What is the hydraulic system for two ways hydraulic  planetary winches.

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     The above diagram is workable for TD20000/30000 or TE9.0 series  

     Hydraulic Recovery Winch