WEG MPW Motor Protection
Adjustable thermal-magnetic protection for motors up to 100 A.
MPW motor protection breakers combine manual motor control with adjustable thermal and magnetic trip elements. Coordinate them with RW overload relays, SRW safety relays, and CW contactors to deliver compact, fully protected motor starters.
Frame Sizes
0.1–16 A adjustable thermal trip with 100 A short-circuit rating using recommended fuses.
0.1–32 A adjustable range with interchangeable terminals and direct mounting to contactors.
25–100 A coverage with bolt-on terminals and external shunt/undervoltage releases.
Trip Elements
Dial-set trip points for precise motor FLA coordination with clear scale markings.
Fixed instantaneous trip at 12–15x In to protect against short circuits.
Optional alarm contacts indicate thermal trip, short circuit, or manual OFF status.
Accessories
- Side-mount auxiliary contacts (1NO/1NC, 2NO/2NC) and front-mount auxiliary blocks.
- Shunt trips, undervoltage releases, and lockable handles for remote disconnect requirements.
- Busbar adapters and feed-in blocks for quick assembly with CW contactors.
- Enclosure kits with rotary handles for local isolation and NFPA 79 compliance.
Coordination Benefits
- UL 508 Type E self-protected combination when paired with CW contactors and RW overload relays.
- Short-circuit ratings up to 65 kA with recommended fuses or MCP combinations.
- Direct mounting to contactors reduces panel depth and wiring time.
- Trip indication window and manual reset simplify diagnostics.
Complete Motor Protection Strategy
Integrated Disconnect
MPW breakers combine isolation and overload protection, eliminating the need for separate switch-disconnects.
Fast Coordination
Use MPW with RW overloads or RW-E electronic relays for Type 2 coordination and selective trip curves.
Field Adaptable
Retrofit shunt trips, aux contacts, and rotary operators in the field without removing wiring.
Harsh Duty Ready
Withstand ambient up to 60 °C with derating curves and maintain IP20 finger-safe terminals.
Motor Protection Selection Snapshot
| Model | Adjustment Range | Breaking Capacity | Key Applications |
|---|---|---|---|
| MPW16 | 0.1–16 A | 50 kA @ 480 VAC with fuses | Conveyors, fans, and OEM machinery with fractional to 10 HP motors. |
| MPW32 | 0.1–32 A | 65 kA @ 480 VAC with fuses | Pumps, compressors, and packaging lines up to 25 HP. |
| MPW100 | 25–100 A | 42 kA @ 480 VAC with fuses | Process motors, HVAC blowers, and specialty machines up to 60 HP. |
| RW-E Electronic Relay | 0.5–840 A (via CTs) | Programmable with ground fault and thermal modeling | Critical process loads requiring diagnostics, communications, and remote reset. |
Starter Package Engineering
Pair MPW breakers with CW contactors and SSW soft starters for complete motor protection assemblies. Gross Automation engineers deliver layout drawings, wiring diagrams, and commissioning documentation.
- Provide motor data and duty cycle to size trip settings and accessories.
- Receive UL508A panel layouts with coordinated starter sections and terminal plans.
- Integrate with PLC500 or safety relays for remote trip indication and diagnostics.
- Field support for setting verification, thermal calibration, and maintenance training.
Deliverables
Settings Worksheet
Document thermal setpoints, short circuit calculations, and coordination verification.
Wiring Packages
Point-to-point diagrams, terminal schedules, and accessory wiring for shunt/UV releases.
Maintenance Guides
Inspection intervals, torque charts, and reset procedures for plant technicians.
Documentation & Tools
- MPW selection guide with trip curve references and accessory ordering codes.
- Motor protection settings worksheet aligned with NEC and IEC guidelines.
- Starter coordination tables pairing MPW with CW contactors and RW overloads.
- Enclosure accessory guide with rotary handles and shaft length charts.
Need Help Sizing Protection?
Our engineering team reviews load profiles, ambient conditions, and short-circuit data to recommend the right MPW frame, accessories, and coordination approach.
Schedule a Review