Nord Drivesystems SK 510P, Руководство с инструкциями по установке

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NORDAC PRO (SK 500P) – Manual with installation instructions
34 BU 0600 en-3221
2.3.2 Monitoring of the braking resistor
To prevent overload of the braking resistor, it should be monitored during operation. The most reliable
method is thermal monitoring with a temperature switch which is mounted directly on the braking
resistor.
2.3.2.1 Monitoring with a temperature switch
As standard, SK BR2-… braking resistors are equipped with a suitable temperature switch.
Typically, evaluation of the temperature switch is performed by an external control system.
Alternatively, the temperature switch can be evaluated directly by the frequency inverter. To do this, it
must be connected to a free digital input. This digital input must be parameterised with the function
{10}
“Block voltage”
.
Example, SK 5xxP
• Connect the temperature switch to digital input 4 (Terminal 43 / 24)
• Set parameter
P420 to function {10}
“Block voltage”
.
The switch opens if the maximum permissible temperature of the braking
resistor is reached. The output of the frequency inverter is blocked. The
motor runs down to a standstill.
2.3.2.2 Monitoring with current measurement and calculation
As an alternative to direct monitoring with a temperature switch, it is also possible to use indirect,
arithmetical monitoring of the braking resistor load on the basis of measurement values.
This software-assisted indirect monitoring is activated by setting parameter P556
“Braking resistor”
and P557
“Brake resistor type”
. The actual calculated resistor load can be read out in parameter P737
“Usage brake resistor”
Overload of the braking resistor results in a shut-down of the frequency inverter
with the error message E3.1
"Overcurrent Chopper I²t“
Information
Indirect monitoring using measurement of electrical data and calculation is based on standard
ambient conditions. In addition, the calculated values are reset when the frequency inverter is
switched off. It is therefore not possible to detect the actual load on the braking resistor.
It is therefore possible that an overload may not be detected and the braking resistor or its
environment may be damaged due to excess temperatures.
Reliable temperature monitoring is only possible with the use of a temperature switch.