PRODUCT DESCRIPTION
30.30.01.01117/06
www.schmalz.com
EN | 13
Step 2: Determining the drive group according to load hours
Using the load collective determined in the first step, the appropriate drive group for the load on the
chain hoist can be determined based on the average daily running time of the chain hoist.
First, the average running time of the chain hoist per working day is calculated using the following
formula:
Average running time of the chain hoist per working day in h =
(lifting height in m x lifting operations per hour x 2 x working hours per day in h)
(lifting speed in m/min x 60)
To make things simpler, 1.3 times the average value of the lifting speeds of the creep and fast gears
can be taken as the lifting speed.
The drive group is then determined based on load hours using the following table.
Table 1: Load collective
Drive group according to ISO 4301-1
M3
M4
M5
M6
M7
Load collective
Average running time per working day [h]
1 Low: k < 0.50
up to 2
2
– 4
4
– 8
8
– 16
Over 16
2 Moderate: 0.50 < k < 0.63
up to 1
1
– 2
2
– 4
4
– 8
8
– 16
3 High: 0.63 < k < 0.80
up to 0.5
0.5
– 1
1
– 2
2
– 4
4
– 8
4 Very high: 0.80 < k < 1.00
up to 0.25
up to 0.5
0.5
– 1
1
– 2
2
– 4
Step 3: Determining the drive group according to switching operations
To calculate the switching load, the number of lifting operations must be multiplied by a factor of six
(6).
Calculation of the number of switching operations per hour:
Switching operations per hour = lifting operations per hour x 6
The drive group is selected according to the following table:
Step 4: Determining the drive group according to the duty cycle
The duty cycle of a chain hoist is the actual running time of the chain hoist during which the motor is
running relative to the overall usage time during which loads are being moved.
To make things simpler, the duty cycle can be calculated as a proportion of the running time of the
chain hoist per working hour using the following formula.
To make things simpler, 1.3 times the
average value of the lifting speeds of the creep and fast gears can be taken as the lifting speed.
The drive group is selected according to the following table:
Duty cycle
< 25%
< 30%
< 40%
< 50%
< 60%
Drive group
M3
M4
M5
M6
M7
Step 5: Selecting the correct chain hoist
The correct chain hoist can be selected according to the table in chapter 3.1. The drive group selected
must be the highest drive group as determined in the preceding steps:
Switching operations/h
<150
<180
<250
<300
<360
Drive group
M3
M4
M5
M6
M7
Duty cycle =
lifting height in m x lifting operations per hour x
2
lifting speed in m/min x 60
