Description
1. At-A-Glance Executive Brief
- Model: MS31W12-A
- Brand: GE (General Electric)
- Part Type: M-Pact Plus Air Circuit Breaker (ACB)
- Series: M-Pact Plus (Size 1)
- System Compatibility: GE Low-Voltage Switchgear and Main Distribution Panels
- Weight: 45 kg (Approx.)
2. Technical Introduction
- Problem: Industrial switchgear facilities face catastrophic downtime and arc flash risks when aging main incoming air circuit breakers experience mechanical spring-charge fatigue or trip unit failures.
- Agitation: Procuring exact-fit legacy replacement breakers with matching physical frame dimensions and busbar orientations without triggering expensive switchgear modifications is notoriously difficult.
- Solution: The GE MS31W12-A slides directly into existing M-Pact Plus drawout cassettes, restoring reliable high-current circuit protection and remote telemetry access to critical plant distribution networks.
3. Core Technical Specifications
| Parameter | Value |
| Manufacturer | General Electric (GE) |
| Series | M-Pact Plus |
| Part Number | MS31W12-A |
| Product Type | Air Circuit Breaker (ACB) |
| Frame Size | Size 1 |
| Mounting Type | Drawout (Withdrawable) |
| Number of Poles | 3-Pole |
| Rated Current (In) | 1250 A |
| Rated Operational Voltage | 690 VAC |
| Ultimate Breaking Capacity (Icu) | 50 kA |
4. Field Engineer’s Tech Notes
- Cassette Interlock and Racking Alignment: When racking the breaker from the “Test” to the “Connected” position, ensure the secondary disconnect plug is fully engaged and locked. Misaligned racking screws will trip safety shutter interlocks and prevent main contact closure.
- Spring Charging Motor Maintenance: If utilizing the motorized charging option, periodically inspect the limit switches and gear train for carbon dust accumulation. Manual spring-charge handles should be verified for smooth mechanical engagement prior to emergency restoration.
5. Adaptive QA & Testing Protocol
Every inventory unit undergoes bench testing to validate hardware reliability prior to dispatch. For the MS31W12-A air circuit breaker, our technicians execute primary and secondary current injection testing to verify electronic trip unit parameters (long-time, short-time, instantaneous, and ground-fault protection curves). Mechanical operations testing, including open/close timing, spring-charge motor cycle endurance, and cradle position interlock verification, are performed under simulated conditions. Complete test reports and pre-shipment functional verification videos are available upon request.
6. Buyer’s FAQ
- What is the standard warranty coverage for this air circuit breaker?All units—whether New Surplus Factory Packed (NSFP) or fully tested/refurbished—carry a comprehensive 12-month operational warranty from the date of purchase.
- How fast can this breaker be shipped for emergency plant outages?In-stock items ship the same business day if ordered before our daily carrier cutoff, with freight and crated air delivery options tailored for heavy industrial assets.
- Does this part include the drawout cassette or just the breaker chassis?The MS31W12-A part number designates the breaker body assembly. If you require a matching cradle or cassette unit, specify your bus configuration requirements with our sales team prior to dispatch.
