Description
ABB RVAR-5612
- Technical Specifications (typical dV/dt reactor for ACS800/ACS880 frame):
- Rated Current: Matches drive rated output current (e.g., 12 A, 25 A, 45 A … up to several hundred A — “5612” may encode current & inductance in ABB internal code)
- Inductance: 1.5–3 % of drive base impedance @ rated current (typical 0.05–0.5 mH depending on frame)
- Voltage Class: 400 V / 500 V / 690 V AC (match drive line voltage class)
- Frequency: 0–500 Hz (designed for PWM harmonic spectrum)
- Cooling: Natural convection (small) or fan (large frame)
- Insulation: Class F (155 °C) winding; vacuum-impregnated
- Enclosure: IP00 (open core & coil) for panel mounting; sometimes in IP20 vented steel case
- Operating Temp.: –25 °C to +40 °C (derate above +40 °C)
- Mounting: DIN rail (small) or floor-mount with feet (large) — 4×M6/M8 bolts
- Functional Features:
- Extends motor insulation life on long-feeder applications
- Reduces bearing currents slightly (main mitigation = shaft grounding + insulated NDE bearing + common-mode choke — dV/dt reactor is first line for winding)
- Compatible with ABB drive auto-tuning — drive sees reactor as part of motor impedance; no special drive parameter (though some drives have “Output Reactor Fitted” flag to adjust overcurrent detection)
- Application Scenarios:
- ACS880 driving >50 m motor cable to old 415 V induction motor in pump house
- Paper machine sectional drive — long cable runs to motors in different sections
- Retrofit where original motor failed due to VFD-induced overvoltage — add RVAR reactor + verify cable length
- Material & Structure:
- Core: Grain-oriented silicon steel laminations (EI or toroidal) with air-gap adjusted for linear inductance
- Winding: Enameled copper wire, Class F insulation, polyester-imide / amide-imide
- Terminals: Stud / busbar (large) or screw terminal (small)
- Frame: Welded steel channel base; core & coil epoxy-fixed to prevent vibration noise
- Working Principle:
The series inductance L opposes rapid di/dt → slows the voltage rise at motor terminals because V(t) ≈ L·di/dt. By increasing effective line inductance, the PWM edge (typically 0.1–1 µs rise time from IGBT) is stretched to 1–2 µs → peak reflected voltage reduced from 2×DC (e.g., 1100 V on 400 V drive) to nearer √2·VL-L (≤600 V) — within motor insulation capability.
- Installation Requirements:
- Mount between VFD output terminals (U/T1, V/T2, W/T3) and motor cable — never between line supply and VFD input
- Tighten terminal bolts to specified torque (typically 2–5 N·m for small; 10–20 N·m for large studs) — loose connection → overheating
- Keep reactor away from heat sources; ensure airflow (natural convection)
- Verify motor cable length after installation — if still >100 m even with reactor consider sine-wave filter (RVSF type) instead
- In drive: optionally set Parameter 20.xx “Output Reactor Fitted = YES” — adjusts overcurrent detection slightly; not mandatory but good practice
- Precautions:
- Reactor causes small voltage drop (typically 1–3 % of VFD output) → motor terminal voltage slightly lower than VFD terminal voltage — negligible for most pumps/fans; for precise speed control verify acceptable
- Do NOT use on VFD input (line side) — line side needs input AC line reactor (separate ABB catalog item — e.g., ACL series) not dV/dt reactor
- For very long cables (>150–200 m) or if motor is >3.3 kV or very old — consider sine-wave filter (output LC filter) rather than just dV/dt choke — consult ABB drive application guide
- Periodically check terminal tightness (vibration can loosen — annual/biannual PM)
