RELIANCE 846747-RB original three-phase SCR thyristor rectifier power stack
846747-RB is Reliance Electric original three-phase SCR thyristor rectifier power stack for mid-range MaxPak & FlexPak DC drive systems, OEM production discontinued, supplied by surplus new stock and fully tested refurbished spare parts only. It is an integrated power assembly composed of SCR power chips, dual-side finned aluminum radiator, gate trigger small PCB and built-in RC snubber absorption circuit. It converts three-phase industrial AC input into adjustable DC output to supply DC motor armature loop, matched with 846723T main control board to constitute complete phase-shift speed regulating power loop. RB suffix means revised mechanical structure plus built-in full RC absorption snubber circuit design, different from standalone surge-resistor SR type.
Description
1. Product Brief Introduction
846747-RB is Reliance Electric original three-phase SCR thyristor rectifier power stack for mid-range MaxPak & FlexPak DC drive systems, OEM production discontinued, supplied by surplus new stock and fully tested refurbished spare parts only. It is an integrated power assembly composed of SCR power chips, dual-side finned aluminum radiator, gate trigger small PCB and built-in RC snubber absorption circuit. It converts three-phase industrial AC input into adjustable DC output to supply DC motor armature loop, matched with 846723T main control board to constitute complete phase-shift speed regulating power loop. RB suffix means revised mechanical structure plus built-in full RC absorption snubber circuit design, different from standalone surge-resistor SR type.
2. Model Definition
846747: Base part number of medium-current three-phase full-controlled SCR rectifier stack for Reliance standard DC drive platform.R: Revised mechanical structure, optimized radiator fixed hole spacing and shock-resistant mounting structure compared to original base version.B: Built-in full RC absorption circuit on each thyristor branch (RC buffer capacitor+resistor integrated inside stack), standard RC configuration suffix.
3. Technical Specifications
Rated three-phase input AC 380V/460V 50/60Hz, input voltage fluctuation tolerance ±10%; continuous rated DC output current 125A, 60s short-time overload peak 210A; single SCR reverse blocking voltage 1800V, isolation withstand voltage between main power loop and trigger control loop 2500Vrms. Operating ambient temperature: -5℃ ~ +60℃, relative humidity 5%~95% non-condensing. Adopts double-sided aluminum fin radiator with natural air cooling, net weight approx 3.1kg; integral MOV varistor overvoltage protection + full-branch built-in RC snubber for spike suppression.
4. Interface and Communication Configuration
External large-size screw terminal blocks for three-phase AC input terminals and DC positive/negative power output terminals to connect drive cabinet main power bus. Small pin plug terminals reserved on top trigger auxiliary PCB for hardwire trigger pulse wiring from 846723T control board. No RS485, fieldbus or digital communication ports; all trigger, fault feedback signals adopt discrete hardwire wiring only.
5. Core Functions
Realize three-phase full-controlled phase-shift rectification via SCR phase trigger signal from main control board, adjust DC output voltage synchronously to control DC motor rotating speed. Built-in branch RC absorption circuit suppresses SCR turn-off voltage spike and instantaneous grid surge, reduce semiconductor breakdown risk; built-in overcurrent & short-circuit fault feedback circuit sends abnormal signal back to control board to lock trigger output and implement drive safety shutdown protection.
6. Application Scenarios
Compatible with Reliance MaxPak Plus, FlexPak3000 medium-power DC speed control drives, supporting matching with 846723T control card; widely used for spare replacement of wire drawing machines, small calender, auxiliary papermaking roller transmission DC drive rectifier module on metallurgy, rubber and plastic old production lines.
7. Operation and Maintenance Instructions
Cut off drive cabinet total AC power and wait more than 60min to release residual high voltage inside RC capacitors before disassembly wiring and module replacement for high voltage safety. Quarterly maintenance: use dry low-pressure compressed air to clear radiator gap dust, prohibit solvent liquid directly contacting internal RC components and SCR chips. Once internal SCR breakdown, RC component burnout occurs, replace entire rectifier stack assembly instead of partial component repair; spare modules shall be stored in constant-temperature dry anti-static warehouse to avoid damp and static damage.
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