Technical Documents


Note on using electric winch

Fleet angle
The fleet angle is an angle (θ) formed with the following L1 and L2.
- L1: Perpendicular line toward the drum from the pulley
- L2: Line that connects the center of the pulley and the drum plate

(A) When using a drum with a groove, set this angle (θ) to 4 degrees or less
(only for the first layer of the drum) .
(B) When using a drum without a groove, set this angle (θ) to 2 degrees or less
(only for the first layer of the drum).

* If this angle (θ) is larger than above-mentioned, the wire rope is wound unevenly or overlapped when it approaches to the edge of the drum.
Note: When using a drum without a groove, the distance between the winch and the pulley must be more than 15 times the width of the drum.


Wind the three wraps or more the extra maintenance winding.
The extra maintenance winding is specified for at least two wraps by Japanese Industrial Standards, but it is necessary at least three wraps. If possible, it is preferred more than five wraps. Insufficient extra maintenance winding may cause an accident due to inadequate frictional force.

Relationship between the number of times in extra maintenance winding and the force applied to the end of the wire rope anchored to the drum

Number of times in extra maintenance winding
0
1
2
3
4
Force applied to the end of the wire rope anchored to the drum
1
0.45
0.20
0.086
0.038

 


Calculation method of duty factor

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 (total cycle time).
Duty factor (%ED)= Tb/(Tb+Ts) × 100 (%)

- Tb : Total load operating time
- Ts : Total resting time
- Tb + Ts = Approximately 1 to 10 minutes should be set


Calculation method of allowable length for electric wire

Please note that the voltage drop due to the length and diameter of electric wire.

Note that voltage drop interferes with operation of electric winches. Select the electric wire of appropriate length and diameter in the following formula because voltage drop is affected by the length and diameter of it.
* Maintain voltage drop within 2%.

Effective length of electric wire: In the case of three-phase
- L (m)=

Effective length of electric wire: In the case of single-phase
- L (m)=

- L (m) = Effective length of electric wire: In the case of single-phase
- L (m) = L : Effective length of electric wire (m)
- A : Sectional area of electric wire (mm2)
- e : Line voltage drop (V)
- I : Current (A)


Calculation formula of the drum capacity (For reference)

Winding length of wire rope
Figure 1 shows the previous way of thinking about the wire rope that is wound onto a drum. In the layer above second, the overlapped wire rope in the upper layer fits into the groove between the adjacent wire ropes in the lower layer. Here, however, as shown in Figure 2, the calculation is performed by closely aligned winding because it suits to the current state and facilitates calculation. (The following formula is for reference to the design criteria of an electric winch according to Japanese Industrial Standards, and is not regulations.)


- Drum shape: Do mm
- Wire rope diameter: d mm
- Pitch circle diameter of the wire rope on the drum: D=(Do+d )mm
- Pitch circle diameter of the wire rope in the i-th layer: Di =Do+(2i-1) x d mm
- Drum width: B mm
- Winding length of wire rope: L mm
- Diameter of drum flange: Df mm
- Standard layer: Ds = (Do+Df)/2 mm
- The standard layer is defined by the pitch circle diameter (Di) of the wire rope on the layer that the calculated value (Ds) is the closest to the whole number.


- Length of wound wire rope on the 1st layer (m) L1=π(B/d-1) x (Do +d )/1,000
- Length of wound wire rope on the 2nd layer (m) L2=π(B/d-1) x (Do +3d)/1,000
- Length of wound wire rope on the 3rd layer (m) Li=π(B/d-1) x {Do+(2i-1) x d}/1,000
- Length of wound wire rope on the n-th layer (m) Ln=π(B/d-1) x {Do+(2n-1) x d}/1,000
Outermost layer (mm)  n=(Df-Do)/2d-1 (Truncate to a whole number)
- Winding length of a wire rope (m) L=L1+L2+.........+Ln

Therefore, the winding length of a wire rope represents the overall length of the wire rope including the extra maintenance winding. Extra maintenance winding is to maintain at least three wraps of wire rope on the drum to anchor the end of the wire rope securely when unwinding entire wire rope.


Example: In the case of Model GM-10
- Wire rope diameter : d=8mm
- Drum diameter : Do=76.3mm
- Diameter of drum flange : Df=175mm
- Drum width : B=170mm
- Rated wire rope tension : Wr=9,800N (1,000kgf)

Winding layer
Pitch circle diameter D (mm)

Maximum wire rope tension N (kgf)

Wire rope on each layer (mm)
Cumulative winding length (mm)
Remarks
1
84.3
9,800 (1,000)
5.36
5.36
Pitch circle diameter of wire rope on the drum D
2
100.3
9,800 (1,000)
6.38
11.74
 
3
116.3
9,800 (1,000)
7.39
19.13
Rated wire rope tension in standard layer Wr
4
132.3
8,614 ( 879)
8.41
27.54
 
5
148.3
7,683 ( 784)
9.43
36.96
Winding length L

 


Example of installation on Maxpull winch


As shown in the figure, users can install a Maxpull winch at any angle up to 360 degrees.


The following arrow indicates the range of the wire rope winding direction.




The above shows the winding direction of standard products. Please order the Type LUSI of each model when required to lift a load by rotating the handle counterclockwise. (The winding direction of the wire rope changes to the opposite direction shown in the above figure).
Example Model GM-20-LUSI


Wire rope tension by using Maxpull winch


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