Siemens 3TF4922-OXMO Power Contactor

Siemens 3TF4922-OXMO — Stop the Clock on Your Downtime. Ship Today.

Every minute a motor control center sits dead, you’re bleeding money. A tripped contactor in a conveyor drive, a crane hoist that won’t energize, a pump station that’s gone dark — the 3TF4922-OXMO is the part that puts it back online. We stock it. We ship it. We’ve done this before, and we know you don’t have time to wait two weeks for a distributor to locate one.

This is a 3-pole, heavy-duty AC power contactor from Siemens’ SIRIUS 3TF platform — a workhorse that’s been in motor control panels across steel mills, water treatment plants, and automated production lines for decades. The 22 auxiliary contact configuration (2 NO) means it drops straight into standard interlock and feedback wiring without add-on blocks. The OXMO suffix designates a special coil voltage variant — confirm your coil voltage before ordering, and contact us if you need verification support.

URGENT REQUIREMENT? Contact: [email protected] | WhatsApp: +86 18359268345

Quick Technical Datasheet

Troubleshooting & Replacement Tips

Common failure signatures for the 3TF49 series:

• Coil burnout (A1/A2): Typically caused by sustained overvoltage on the control circuit or a stuck-open main contact forcing the coil to stay energized under load. Measure coil resistance before condemning — an open circuit or near-zero reading confirms coil failure. Check your control voltage rail for spikes if this is a repeat failure.
• Welded main contacts: Symptom is motor runs continuously even after the control signal drops. Caused by high inrush on AC-4 duty or undersized contactor for the actual load. When replacing, verify the motor FLA and starting category — if the application is AC-4 (plugging/inching), you may need to upsize.
• Chattering / humming coil: Usually a low or fluctuating control voltage. On AC coils, also check the shading ring on the magnet face — a cracked or missing shading ring causes 100/120 Hz chatter and rapid contact wear.
• Auxiliary contact failure: The 2 NO contacts on the 22 configuration are often used for PLC feedback or interlock logic. If your PLC input shows intermittent signal loss, check contact gap and spring tension before replacing the whole unit — auxiliary contact blocks on the 3TF series are field-replaceable.

Replacement procedure — field checklist:

1. Isolate and lock out the upstream circuit breaker (LOTO). Verify zero voltage at L1/L2/L3 with a calibrated meter.
2. Photograph the existing wiring layout before disconnecting — especially auxiliary contact wiring, which varies by application.
3. Note the coil voltage marked on the nameplate of the failed unit. The OXMO suffix means this is a special coil variant — the replacement must match exactly. Do not substitute a standard coil voltage without engineering sign-off.
4. Disconnect main power terminals (T1/T2/T3 first, then L1/L2/L3), then control terminals (A1/A2), then auxiliary contacts.
5. If an overload relay (3RU/3RB) is mounted directly on the contactor base, unclip it before removing the contactor from the DIN rail. It can be remounted on the new unit without recalibration if the motor FLA setting hasn’t changed.
6. Mount the new 3TF4922-OXMO, reconnect in reverse order. Torque main terminals to spec (refer to Siemens installation datasheet for terminal torque values by wire size).
7. Before energizing, manually depress the contactor armature to verify free mechanical movement and confirm no contact welding on the new unit.
8. Energize control circuit only first — listen for clean single-click engagement with no chatter. Then restore main power and verify motor rotation direction.

Configuration note on OXMO suffix: Unlike standard 3TF49 variants with fixed coil voltages (e.g., 24V DC, 110V AC, 230V AC), the OXMO designation indicates a factory-configured special coil. If you are unsure of your coil voltage, check the original unit’s nameplate or your panel schematic. We can cross-reference your application — send us your panel drawing or BOM and we’ll confirm compatibility before shipment.

Reliability in Harsh Conditions

The SIRIUS 3TF platform was not designed for climate-controlled server rooms. It was built for the floor — foundries, offshore platforms, chemical processing plants, and outdoor switchgear enclosures where ambient temperatures swing from sub-zero to 55°C and humidity never drops below 80%.

The 3TF4922-OXMO’s silver-alloy main contacts resist oxidation and arc erosion across millions of switching cycles. The enclosure is rated for protection against dust ingress and condensation when installed in a properly sealed panel. The magnetic circuit uses a laminated iron core that minimizes eddy current losses and maintains consistent pull-in force across the rated voltage range — critical in facilities where control voltage sags during motor starting.

Vibration resistance is validated to IEC 60068-2-6 test profiles, making this contactor suitable for mobile equipment, marine applications, and installations near heavy presses or compressors where panel vibration is a constant. The contact spring system maintains adequate contact pressure even after extended vibration exposure, preventing the intermittent contact resistance that causes nuisance trips and overload relay false-positives.

Thermal performance is equally robust. The coil insulation class and contact carrier material are rated for continuous operation at elevated ambient temperatures without derating — a common failure point on cheaper alternatives that use lower-grade insulation systems. When you’re running a 24/7 production line, that margin matters.

Global Express Logistics

Our warehouse is located in Xiamen, Fujian Province — one of China’s primary export hubs with direct access to DHL, FedEx, and UPS international express networks. For urgent replacement orders, we prioritize same-day or next-morning dispatch for orders confirmed before 15:00 CST.

Typical transit times from Xiamen:

• Southeast Asia (SG, MY, TH, VN, ID): 2–4 business days via DHL Express
• Middle East (AE, SA, QA, KW): 3–5 business days via FedEx International Priority
• Europe (DE, NL, PL, FR, IT): 4–6 business days via DHL Express Worldwide
• North America (US, CA, MX): 4–7 business days via FedEx International Priority
• Australia / New Zealand: 4–6 business days via DHL Express
• South America (BR, CL, CO): 6–10 business days via FedEx or DHL

All shipments include a commercial invoice, packing list, and certificate of origin for customs clearance. For orders requiring HS code documentation or import duty pre-calculation, contact us before placing the order. We handle export licensing and customs paperwork in-house — no third-party freight forwarder delays.

Tracking numbers are issued within 2 hours of dispatch and sent directly to your registered email. For time-critical shipments, we can arrange Saturday delivery or hold-at-location options through DHL and FedEx on request.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
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