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Power management

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Power management
for on-board electrical systems of agricultural and construction machinery.

Construction machinery and agricultural vehicles have one thing in common: they have to be robust and readily available at all times. Downtimes have to be prevented under all circumstances as idle machinery does not “earn” money, but it only costs.  This is all the more important for leased achinery. But also seasonal machinery such as harvesters has to be fully functional during the short time when it comes to use.
No one can afford a standstill due to a failure of the electrical on-board system. Blown fuses can be a nightmare when a replacement is not ready to hand. A jammed relay may put a machine out of service for hours.
For more than 60 years E-T-A has been a eliable partner when it comes to enhancing safety and reliability of machinery.We have always been supporting our customers with designing their electrical equipment, among them many major manufacturers of construction machinery.


Circuit breakers installed a million times over have the confidence of companies like Grimme for their harvesters, Kässbohrer (snowcats), Liebherr and Mecalac (excavators), Terex (construction machinery) or Wirtgen GmbH (asphalt cutters). They all rely on the quality of E-T-A products.
Our sophisticated power management and protection concepts reliably protect wiring and loads against short circuit or overload and support the Design Engineers working on their various tasks.

Why E-T-A?
Ideal cable protection

Connection of line-load-protection
The ideal protection of on-board electrical systems accounts for both cable harnesses and the loads themselves.  The thermal properties of cables can easily be visualised in a current-time chart as a characteristic curve. The critical range lies above this range: the cable may get so hot that a fire hazard cannot be excluded.
Such a chart can also be used to show the trip characteristics of a standard blade fuse and of a circuit breaker for equipment protection as well as the start-up behaviour of a load. Our example shows the curve of a fan motor.


Protection near the line – reliable and cost-effective.
The diagram shows that the trip curve of the protective elements has to lie exactly between the line curve and load curve:
If the trip curve of the fuse or circuit breaker and the line curve have an intersection point, the cable may burn out before the protective element trips and this would cause considerable damage.
It is similar with the load curve: in the event of an intersection – as shown in the chart –, the fuse or circuit breaker will trip although no damage needs to be expected. Normally the cable cross section has been oversized in such a case which leads to additional weight and costs.  The closer the trip curve of the line protection to the line curve, the better the protection of the line. 

For critical thermal environmental conditions there are circuit breakers with temperature compensation. They are fitted with an additional bimetal which depends only on the ambient temperature and thus renders the tripping bimetal independent of the ambient temperature.

Circuit breakers –
Your benefit counts.

The advantages of circuit breakers compared to blade fuses are obvious:

Unlike blade fuses circuit breakers are maintenance-free in the event of a failure.  This provides ease of handling and significantly reduces costs over the entire life span.

A wealth of type configurations
Depending on the application E-T-A circuit breakers can be provided with various kinds of reset features (SAE types I, II, III and III*). Select the ideal product for any application:

  • Autoreset (circuit breaker resets automatically as soon as the short circuit or overload has been remedied)
  • Modified reset (circuit breaker resets by switching the ignition on and off)
  • Manual reset (circuit breaker is reset by actuating its reset button)
  • With additional manual release facility (manual disconnection of the circuit for maintenance or service works or a longer downtime or transportation of the machine).

Clear visual status indication
Even in a crowded fuse box the tripped circuit breaker can easily be identified because of its protruding reset button.

High availability
In the event of a tripped circuit breaker the user can easily reset the breaker and continue working. Deadlines can be met without losing time.

Enhanced safety
Blown fuses are often replaced by unsuitable, but available fuses with a different rating or even bridged by inappropriate substitutes. These hazards are excluded by the use of resettable circuit breakers.

Automatic reset operation makes our circuit breakers suitable for inaccessible locations as they do not have to be actuated nor replaced.

Robust design
Circuit breakers do not age and are not prone to corrosion or wear through shock, or current or voltage peaks. Nuisance tripping is a disadvantage of aged blade fuses in the event of inrush peaks, but is prevented with thermal circuit by the bimetal’s inertia.

Directly interchangeable
The automotive circuit breaker types 1610, 1170 and 1620 have the same ATO or MINI footprint as blade fuses (DIN 72581-3) and can therefore directly replace the fuses. This feature makes our circuit breakers interesting for optional equipment in OEM applications as well s in the retrofit business.

Minimum power loss
The voltage drop of circuit breakers is normally lower than with blade fuses.  Higher cross sections lead to very low internal resistance values which in turn means less power loss and less gas consumption.

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