TCI HGA Manual - Manual (Page 32)

32
Current Transformer Installation
For accurate sensing of the load it is important that the load sensing current transformers are properly
installed.
Warning Only qualified electricians should carry out all electrical installation and maintenance work on the HGA.
Failure to follow standard safety procedures may result in death or serious injury.
Disconnect all sources of power to the drive and HGA before working on the equipment. Do not attempt
any work on a powered HGA. Also, check for zero voltage between all phases of the input and output
lines.
Operating current transformers with the secondary winding open can result in a high voltage
across the secondary terminals which may be dangerous to personnel or equipment.
It is necessary for the HGA to monitor the current in Phase “A” (L1) and Phase “C” (L3). Stand-alone
HGA filters are designed for Line Side current transformer (CT) placement as shown in Figure 4.4a. It
is important that both CTs are on the same side of the HGA. The CTs should be centered around the
conductor. Optional Load Side CT placement is available for single units as shown in Figure 4.4a.
The polarity of the CT is important; the “H1” marking on the CT must face the source. The secondary
windings of the CT around conductor L1 should connect to TB-1 terminals 1 & 2 and the CT around
conductor L3 should connect to TB-1 terminals 3 & 4. The secondary wire of the CT identified as
“X1” must connect to the “X1” terminal of TB-1 for both CTs. Failure to maintain the correct polarity
and phasing will cause an over-current fault. If this should happen refer to the troubleshooting section.
The exact CT placement is dependent on the HGA’s configuration and size. Please refer to Figures
4.4a through 4.4i for the installation that applies.
Note: Units with black “TB-1” terminal blocks are shipped with two position shorting jumpers
installed between positions 1 & 2 and 3 & 4. This is done for your safety and to prevent equipment
damage. The jumpers are installed in the center of the block and can be identified by the gray top.
After the load CTs are installed and wired, these jumpers must be removed for correct unit operation.
They can be removed with a standard flat blade screw driver (See Figure 5.3).
Note: CT operation can be verified via the HMI touchscreen feedback waveform plot screens.
Reference the HMI VLine & ILine Waveform Plot Sub Screen in Section 6 for details.
Table 4.2 – CT Range by Model Size
Amps CT Min Ratio
CT Max
Ratio
Notes
39 250:5 3000:5
Factory technician start up required to
use CTs outside of the published range
50 250:5 3000:5
79 250:5 3000:5
100 250:5 3000:5
200 750:5 3000:5
300 750:5 5000:5
!