Diagnosis and analysis of electric motors

Cranes are designed, built, tested, and planned for challenging scenarios. 

But how they are actually used in practice, and whether all of the parameters stipulated for safe operation are really adhered, are different matters altogether. Many of their general control systems constantly record no more than function-critical parameters, if they record any parameters at all. 

Our motor protection relays have internal, non-volatile memory and a diagnostic port to help users shed light on the vagaries of real-life crane operation.

The following historical and current data is available, depending on the sensors and protective relays used: 

  • Running times
  • Starts and stops 
  • Errors and events 
  • Motor temperature
  • Overload 
  • Faults that have occurred 

In the event of maintenance or a fault, the entire history since commissioning can easily be analyzed on location using an Android device or laptop. 



With its new generation of INT69 Diagnosis, Kriwan has made its flagship protection module even more powerful.

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Motor protection based on PTC sensors is an effective and reliable way of protecting against thermal overload in electrical machinery.

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Secure parameter settings for motor protection relays

Since as far back as 1968, KRIWAN has produced protective relays that cannot have their parameters adjusted on site, the aim being to ensure quick and easy commissioning and prevent improper adjustments. This arrangement safeguards against a bypassing of the protective function caused by people mis-adjusting switches or potentiometers on location. The limit temperature for temperature monitoring is defined by a PTC resistor in the windings, which is tamper-proof. KRIWAN configures the protection devices beforehand with other parameters (such as delay following overload) during production, according to the crane manufacturer’s specifications. 

The new generation of INT89 from KRIWAN goes a step further. The values and parameters in the relay are modified using a digital port on the protective relay and a PC or Android device. Multiple password-protected user levels provide security against improper alteration. Unlike other common adjustment features involving switches and potentiometers, the INT89 is tamper-proof since a screwdriver alone is not enough. Furthermore, commissioning is much simpler than using a PLC. The INT89 can be modified on site using a laptop, smartphone, or tablet after entering a password, and in the manufacturer’s factory parameters can be incorporated into automated processes using a PC, which makes for a highly flexible process with low variation levels.



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