33
EATON
www.eaton.com
Instruction Booklet
IB020003EN
Effective January 2021
AMPGARD RVSS
Reduced Voltage Soft-Starter
User Manual
Figure 24. RVSS SCR truck assembly - rear.
Each Power Pole phase leg assembly includes its SCR heat sink
assembly with SCRs, gate driver board(s), snubber board, gate
fan-out board, and heat sink thermal PTC thermistor feedback. The
SCR truck assembly is mounted in the RVSS medium voltage cell
(see
). Each Power Pole phase leg assembly is a stand-
alone unit and can be easily removed from the truck assembly (see
Figure 25. SCR truck mounted in RVSS cell.
Figure 26. RVSS heat sinks and SCRs.
Figure 27.
Gate Driver
Board
Gate Driver
Board
with PTC
thermal
interface
48V
Power
Isolation
Fan-out
Board
Snubber
Boards
RVSS phase leg assembly.
6.2.1 SCRs
RVSS Power Pole Silicon Controlled Rectifiers (SCRs) are sized for
UL medium-duty 400A. The SCRs are rated for starting duty (short-
time) and must not be run continuously. Under normal conditions,
the SCRs will be used only during a start, and will be bypassed
after a successful start sequence. If a linear deceleration voltage is
employed, the SCRs may also be used to ramp motor voltage down
during a stop sequence.
The number of RVSS trucks will vary upon the motor voltage and
horsepower size, arranged in series and parallel configurations.
6.2.2 Heat-sink arrangement
shows a phase heat sink array for 4160 V applications,
with the connections shown. The SCRs are connected in series-
parallel.