Schneider Electric 58 TRX manual Braking Application-dependent Option, Harmonic Analysis, 141

Altivar® 58 TRX AC Drives

Suggested Specifications

f.There will be 2 analog inputs. 1 analog input will be software selectable and consist of the following configurations: 0-20 ma, 4-20 ma, 20-4 ma, x-20 ma (where x is user defined). The other analog input shall be 0-10 Vdc.

g.There will be 4 isolated logic inputs, 3 shall be user assignable in the software. The selection of assignments, at a minimum, shall consist of run, reverse, jog, ramp switching, plus/minus speed (2 inputs required), setpoint memory, preset speeds (up to 8 speeds), auto/manual control, fast stop, forced local, motor switching, and fault reset.

h.One voltage-free Form C relay output contacts will be provided to indicate AC drive fault status. An additional NO relay contact will be user assignable.

i.There will be one analog output as standard that will be software selectable from 0–20 mA or 4–20 mA to represent a signal proportional to one of the following: motor current, motor speed,

± torque, motor power, PI loop variables, drive or motor thermal states.

j.There shall be available an additional hardware input/output extension card which also provides interlocking and sequencing capabilities. The card shall be fully isolated with pull apart terminal strips. The analog output assignments shall be proportional to the following motor characteristics: frequency, current, power, torque, and thermal state. The output signal will be selectable from 0-20 ma or 4-20 ma. All of the I/O will be user assignable in the software as previously defined.

2.11 Braking (Application-dependent Option)

NOTE: When braking certain types of loads, there is the conversion of kinematic energy into electrical energy by the motor which is returned to the AC drive. Dynamic braking can be chosen to absorb this energy and avoid causing the AC drive to inadvertently shut down. The energy is dissipated across a resistor that is connected to the drive. For constant torque AC drives, the dynamic braking unit must be capable of stopping 1.5 per unit motor torque from base frequency to 0.5 Hz with sensorless flux vector control mode.

a.The dynamic brake resistor shall be provided and connect to existing terminals on the AC drive. The resistor shall mount externally to the AC drive enclosure. A power transistor will be provided in the AC drive to switch the excess energy to the braking resistor. The braking resistor will be of a size calculated to stop 6 times motor inertia at 1.5 per unit motor torque.

2.12 HARMONIC ANALYSIS

NOTE: The amount of harmonic distortion at the point of common coupling (PCC) is due to the distribution system characteristics (impedance of the source) and the power source size relative to the AC drive load. The harmonic current magnitude and voltage distortion values can be predicted through computer modeling. If the resulting calculations determine that the harmonic distortion will be above the IEEE-519 specifications of 5%, isolation transformers or line reactors can be supplied to lower the harmonic levels. The isolation transformers or line reactors are mounted at the AC drive input to reduce the current harmonics that are fed back into the supply.

a.A harmonic analysis shall be performed and priced as a separate line item by the AC drive manufacturer based upon system documentation consisting of but not limited to one-line diagrams and specific distribution transformer information consisting of X/R,%Z, and kVA data. The data shall consist of but not be limited to total harmonic voltage distortion and total rms current.

b.The maximum allowable input line unbalance shall be [5% for 460 V input line short circuit capacity of 15,000 amps] [2.5% for 460 V input line short circuit capacity of 30,000 amps] [.5% for 460 V input line short circuit capacity of 65,000 amps]. If the resulting voltage harmonic distortion exceeds 5%, three phase, line reactor(s) shall be priced as a separate line item.

c.The line reactor(s) if required shall be provided in stand-alone Type 1 enclosures for mounting separately from the AC drive.

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