Duty cycle
The duty cycle ( ED ) is a maximum permissible operating interval for equipment , after which a rest phase must take place in order not to damage or destroy the equipment. The nominal operating modes are specified in DIN VDE 0530-1 , among others .
identification number
The duty cycle can be specified as a size of the dimension number (ratio of usage time to the observation period), for example in percent. As a rule, the period of use is also specified. If not, the usage period is 10 minutes.
- Example DC motor : 20% ED S3 - e.g. B. 2 minutes of operation, then 8 minutes of cooling
A dimensioned duty cycle explicitly indicates the maximum continuous use and the subsequent idle time.
- Example welding machine : 100A / 50% ED S2 30 minutes: weld 15 minutes at 100 A welding current, then 15 minutes break.
Both details can be converted into one another.
The duty cycle can also be used implicitly as a criterion for estimating the load capacity or overload capacity, for the reserves realized in the device design and thus also for quality assessment. In the case of power tools in the DIY sector, only a short ED is usually noted on the devices, whereas a high ED (up to 100%) can be permitted for devices for commercial use.
Operating modes
| VDE 0530-1 | Operating mode |
|---|---|
| S1 | Continuous operation, constant load |
| S2 | Short-term operation, constant load |
| S3 | Intermittent operation without the start-up affecting the temperature |
| S4 | Intermittent operation with the influence of starting on the temperature |
| S5 | Intermittent operation with the influence of starting and braking on the temperature |
| S6 | Continuous operation with intermittent loading |
| S7 | Continuous operation with starting and braking |
| S8 | Continuous operation with load change |
Examples
A duty cycle is specified when a device can only provide the nominal power temporarily. This is usually the case when the heat loss cannot be dissipated quickly enough and damage or premature failure would therefore be expected in the long term.
You can find information on ED z. B. often with the following devices
- Welding equipment
- Electric motors
- DC motors
- Grinding machines
- Heavy current relay
- Solenoid valves
- Kitchen appliances such as hand blenders or coffee grinders
Devices with 100% ED can be operated for any length of time.
literature
- Rotating electrical machines - Part 1: Rating and performance (IEC 60034-1: 2004); German version EN 60034-1: 2004 , 3rd edition VDE 0530-1, VDE Verlag, Berlin, 2005