BENSHAW RSi SG Series, Instruction Manual

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Chapter 3 - Installation
3-10
Drive Capacity
Grounding Wire Sizes, AWG or kcmil (mm
²
)
230V Class 460VClass
600VClass
7.5 ~ 10 HP 10 (5.5) 12 (3.5) 14 (2.5)
15 ~ 20 HP 6 (14) 8 (8) 12 (3.5)
25 ~ 40 HP 4 (22) 6 (14) 8 (8)
50 ~ 75 HP - 4 (22) 6 (14)
100 ~ 125 HP - 2 (38) 4 (22)
150 ~ 200 HP - 1/0 (60) 2 (38)
250 ~ 400 HP - 4/0 (100) 1/0 (60)
500 ~ 600 HP - 300 (150) -
700 HP - 400 (200) -
Use of Isolation Transformers and Line Reactors
In most cases, the SG drive may be directly connected to a power source. However in the following cases a properly
sized isolation transformer or a 3% or 5% line reactor should be used to minimize the risk of drive malfunction.
- When the source capacity exceeds ten (10) times the KVA rating of the drive.
- When power factor capacitors are located on the input source supplying the drive.
- When the power source experiences frequent power transients and/or voltage spikes.
- When the power source supplying the SG drive also supplies other large electrical devices such as DC drives
that contain rectifiers or other switching devices.
- When the drive is powered from an ungrounded (floating) Delta connected source. In this case, establish a
grounded secondary. A drive isolation transformer utilizing a grounded (solid or resistance grounded)
secondary should be used. Other means of establishing a ground may be used.
Motor Lead Length Specifications
Excessive motor lead lengths may adversely affect the performance of the motor. The voltage of the pulses at the
motor terminals can be almost double the input voltage of the drive. This in turn can cause additional stress on the
motor insulation and shorten the life of the motor. The motor manufacturer should be consulted regarding the
specifications of the motor insulation.
A filter may be required to be added to the output of the drive depending on the lead lengths from the drive to the
motor. Contact Benshaw for assistance with selecting the appropriate filter. See the table below.
PWM Carrier Frequency Motor Lead Length Type of Filter
Default Frequency or lower
50 ft. to 300 ft. 1.5% or 3% Load Reactor
300 ft. to 1500 ft. LRC Filter (dV/dT)
>
1500 ft. Sine Wave Filter