GE DS200SVAAG1A Gas turbine DO module

Adjusting the nominal current When the nominal current rating of the motor is less than the nominal current of the drive, it is possible to reduce the maximum value of current produced by the drive by fitting a RIN resistor. Use the following equation to calculate the value of the RIN resistor:Correct setting of RIN resistor is necessary to prevent damage to the motor and to avoid a fire risk in the event of an overload.When the value of the required nominal current is reduced, the resulting IPEAK current may be more than 2 × INOM before the I2t protection reduces the peak current to the nominal value. In this case, the peak current is supplied for less than 2 seconds. Added protection is required to stop the IPEAK value increasing to more than 2 × INOM. See section 5.5.7 Zero speed torque on page 43. When INOM is the theoretical nominal current, and the denominator equals zero, RIN should be open circuit.

Adjusting the peak current RIP resistor 

When a RIN resistor is fitted, IPEAK may become excessively high in relation to INOM. To reduce the value of the peak current, use a RIP resistor.When the peak current is reduced, the ratio between IPEAK and INOM is altered. This alteration increases the time before I2t protection takes place. In this case, the peak current is supplied for more than 2 seconds.Armature feedback mode can be used when a tachogenerator is not fitted to the motor. Speed control is then less precise. Speed is controlled by using the motor voltage as feedback. Voltage drop due to motor resistance can be compensated by adjusting the value of the RAI resistor.

Calculating the value of the RAI resistor

 can be difficult since it is a function of the following: • Motor characteristics. (eg. armature resistance and temperature). • Brush resistance (changing with wear) An approximate value may be found experimentally using a RAI resistor value of 400kΩ to 600kΩ Too low a value for the RAI resistor may modify the velocity loop response. For guidance, contact Control Techniques.1. Set Switch 1/2 at OFF to enable operation with armature feedback. 2. Set Switch 3 at OFF to disable tachogenerator loss protection. 3. Use the following equation to calculate the correct value of RKW resistor: RKW = 132 x Vm x Kemotor

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PLC module, programmable controller, CPU module, IO module, DO module, AI module, DI module

Network communication module,

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Module, redundancy module, power module, relay output module, relay input module, processor module