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Sep 16, 2021

Service Tip - NP impact crusher optimization

The adjustment of the breaker plates is essential to obtain optimal performance of the NP horizontal shaft impact crusher.
Nordberg NP horizontal shaft impact crusher
Nordberg NP horizontal shaft impact crusher

The crushing principle of a horizontal shaft impact crusher


Materials inside an impact crusher, are reduced in size by their impact on the rotor, the impact on the breaker plates and the impact among materials.

The setting of the last breaker plate defines the crusher setting. It also defines the product size.
The setting corresponds to the minimum distance between breaker plate liner and blow bar.


Crusher settings have to be defined according to the application type, feed materials and required product after the crusher.

Once S2 has been defined, a rule of thumb can be used to define S1



S1 = (F100 + S2) / 4 + 25 (mm)
F100 = Max feed size



Feeding : 60/600 (F100)

Setting S2 on a NP1415 impact crusher : 20 mm (see table below)

Calculated setting S1 : (600 + 20) / 4 + 25 = 180 mm


The minimum setting

The value should not be less than the data given in below table! These values are for reference only however, the minimum setting is related to the application.

Minimum setting table

The + advice

Think about it! The blow bar lifting tool supplied with the machine allows you to carry out maintenance operations with greater security


The + product

Rotor Positioning System (RPS)

The RPS has been designed to rotate slowly and lock the shaft line for maintenance operation such as blow bar replacement and setting adjustment.

The RPS system is available in two versions:

  • The mRPS mechnical version or manual Rotor Positioning System (available for all configurations)
  • The eRPS electrical Rotor Positioning System (controlled by IC20C automation).

RPS is EN1009 standard compliant and now mandatory in Europe.

mRPS and eRPS Rotor Positioning System
mRPS and eRPS Rotor Positioning System
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