Baldor VS1SD, Инструкция по установке и эксплуатации

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4-2 Power Wiring MN766
4.2 Line Impedance
Baldor VS1SD drives require 1% line impedance minimum (3% for AA frame size drives and B Frame NEMA 4X drives). If the
impedance of the incoming power does not meet this requirement, a 3 phase line reactor can be used to provide the needed
impedance in most cases. The input impedance of the power lines can be determined as follows:
Measure the line to line voltage at no load and at full rated load.
Use these measured values to calculate impedance as follows:
% Impedance =
No Load Full Load
Volts Volts
x 100
No Load
Volts
4.2.1 Line Reactors
Three phase line reactors are available from Baldor. The line reactor to order is based on the full load current of the motor
(FLA). If providing your own line reactor, use the following formula to calculate the minimum inductance required.
Where:
L =
X
(I
X
√
3 377)
0.01)
L- L
(V
X
L Minimum inductance in Henries.
L- L
V Input volts measured line to line.
0.01 Desired percentage of input impedance 1%.
(Note: Change this value to
0.03 for AA Frame Size drives.)
I Input current rating of drive.
377 Constant used with 60 Hz power.
Use 314 if input power is 50 Hz.
4.2.2 Load Reactors
Line reactors may be used at the drive output to the motor. When used this way, they are called Load Reactors. Load
reactors serve several functions that include:
• Protect the drive from a short circuit at the motor.
• Limit the rate of rise of motor surge currents.
• Slowing the rate of change of power the drive delivers to the motor.
Note: The wire leads that connect the motor to the control are critical in terms of sizing, shielding and the cable
characteristics. Short cable runs are usually trouble free but fault-monitoring circuitry can produce numerous faults
when long cables (over 200 feet) are used.
• 200+ft (60m): Baldor recommends adding an optional load reactor to the output of the control.
• 300+ft (90m): Baldor recommends adding an optional load reactor and common mode choke to the control.
The load reactor and/or common mode choke should be placed in close physical proximity to the control.
Unexpected faults may occur due to excessive charging current required for motor cable capacitance. If you use
long motor leads and experience unexpected trips due to overcurrent conditions and are not sure how to correctly
size and connect the optional load reactors, contact your local Baldor District Offi ce.
Load reactors should be installed as close to the drive as possible. Selection should be based on the motor nameplate FLA
value.
4.3 Line Disconnect
A power disconnect should be installed between the input power service and the drive for a fail safe method to disconnect
power. This drive will remain in a powered-up condition until all input power is removed from the drive and the internal bus
voltage is depleted.