Siemens 3RN1010-1CB00 Thermistor Motor Protection Relay

Siemens 3RN1010-1CB00 — Stop the Clock on Motor Downtime, Ship Today

Every hour a motor sits offline costs money. In pump stations, compressor halls, and conveyor lines, a failed thermistor protection relay means the entire drive train is locked out — and production stops. The Siemens 3RN1010-1CB00 is a 24 V AC/DC PTC thermistor motor protection relay from the SIRIUS 3RN series, and we stock it in Xiamen for same-day dispatch. No waiting on factory lead times. No chasing distributors. You send the RFQ, we confirm stock, and the unit is on a DHL or FedEx flight within hours.

The 3RN1010-1CB00 is the workhorse of Siemens motor protection: compact, DIN-rail mounted, IEC 60947-8 certified, and designed to interface directly with PTC thermistors embedded in motor windings. When winding temperature crosses the thermistor trip threshold, the relay opens its NC contact and drops the contactor coil — before insulation degrades, before bearings seize, before you’re looking at a rewind job. That’s the engineering logic. Our job is to get you a verified original unit before the next shift starts.

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

Quick Technical Datasheet

Troubleshooting & Replacement Tips

Field experience with the 3RN1010-1CB00 surfaces the same failure patterns repeatedly. Here is what to check before and after swapping the relay:

Symptom: Relay trips immediately on power-up, motor never starts.
Root cause 80% of the time: the PTC sensor circuit is open. Measure resistance across terminals A1–A2 (sensor input). A healthy PTC string at ambient temperature reads 250–2,500 Ω. An open circuit (>50 kΩ) means a broken sensor lead, corroded terminal, or a sensor that has already thermally failed and not recovered. Do not assume the relay is faulty — verify the sensor loop first.

Symptom: Relay trips intermittently under load, resets after cooling.
This is the relay doing exactly what it is designed to do. The motor winding temperature is genuinely reaching the PTC trip point (typically 130–150 °C for standard Class F insulation sensors). Check motor ventilation, load cycle, and ambient temperature in the motor enclosure. Replacing the relay without addressing the thermal root cause will result in repeat trips within hours.

Symptom: Relay does not trip despite confirmed motor overtemperature.
Check that the reset selector is not stuck in AUTO with a welded output contact. Measure continuity across the NC contact (terminals 95–96) with supply voltage applied and no trip condition — it should be closed. If the contact reads open under normal conditions, the relay output stage has failed and replacement is required.

Replacement procedure — key steps:

1. Isolate control supply voltage (24 V AC/DC) to the relay before removal. Do not rely on the motor contactor being open — the relay supply is independent.
2. Note the reset mode selector position (AUTO / MANUAL) on the old unit before removal. The new 3RN1010-1CB00 ships with the selector in MANUAL by default.
3. Verify terminal wiring against the circuit diagram: A1/A2 = PTC sensor input; 13/14 = NO contact; 95/96 = NC contact. Miswiring A1/A2 to the control supply will destroy the relay input stage instantly.
4. After installation, apply 24 V supply with the PTC sensor connected. The green LED should illuminate within 2 seconds, confirming a healthy sensor loop. If the LED flashes or the relay trips immediately, recheck sensor resistance.
5. No firmware, DIP switches, or addressing configuration required — the 3RN1010-1CB00 is a hardwired relay with no digital parameterization. Plug-and-play replacement for any existing 3RN1010-1CB00 installation.

Compatibility note: The 3RN1010-1CB00 (24 V AC/DC) is not interchangeable with the 3RN1010-1BB00 (110–130 V AC) or 3RN1010-1GB00 (230 V AC). Confirm your control circuit voltage before ordering. If you are unsure, send us the nameplate photo and we will confirm the correct variant.

Reliability in Harsh Conditions

The SIRIUS 3RN series is not designed for clean-room environments. It is built for the conditions that actually exist in industrial plants: vibration from adjacent machinery, ambient temperatures that swing from −25 °C in outdoor substations to +60 °C inside poorly ventilated control cabinets, and humidity levels that condense on terminal blocks during seasonal temperature shifts.

The 3RN1010-1CB00 housing is a glass-fiber reinforced thermoplastic rated to withstand continuous mechanical vibration per IEC 60068-2-6 (10–150 Hz, 1 g). The relay contact mechanism uses silver alloy contacts with gold flash on the NC contact to maintain low contact resistance even after extended periods without switching — a common failure mode in backup protection relays that sit idle for months. The PCB conformal coating provides protection against condensation and airborne contaminants including oil mist and metallic dust, which are endemic in motor control centers adjacent to machining or casting operations.

Siemens validates the 3RN series against IEC 60068-2-30 damp heat cycling (40 °C / 93% RH, 6 cycles) and IEC 60068-2-14 thermal shock (−40 °C to +85 °C, 30-minute dwell). These are not marketing claims — they are type-test results documented in the Siemens SIRIUS product certification files. When you install a genuine 3RN1010-1CB00, you are installing a component that has passed these tests. Counterfeit or grey-market substitutes have not.

Global Express Logistics

Our warehouse is located in Xiamen, Fujian Province — one of China’s primary export hubs with direct access to Xiamen Gaoqi International Airport and daily consolidated freight departures to DHL, FedEx, and UPS international gateways.

Standard express timeline (door-to-door):

• Southeast Asia (Singapore, Thailand, Malaysia, Vietnam): 2–3 business days via DHL Express
• Middle East (UAE, Saudi Arabia, Qatar): 3–4 business days via FedEx International Priority
• Europe (Germany, Netherlands, UK, Poland): 3–5 business days via DHL Express Worldwide
• North America (USA, Canada, Mexico): 4–5 business days via FedEx International Priority
• South America (Brazil, Chile, Colombia): 5–7 business days via DHL or UPS Expedited
• Africa and remote destinations: 5–10 business days; contact us for carrier options

Every shipment includes a commercial invoice, packing list, and certificate of origin. For orders requiring import clearance documentation (HS code 8536.49 for relay components), we prepare the paperwork in advance to avoid customs delays. For emergency shutdown situations, we can arrange same-day dispatch for orders confirmed before 14:00 CST — contact us directly to confirm cut-off time on the day of your order.

All units are packed in anti-static bags inside rigid corrugated cartons with foam inserts. The 3RN1010-1CB00 is a relay with sensitive contact mechanisms — we do not use bubble wrap alone for international freight. Packaging is designed to survive the handling conditions of express air freight, not just local courier delivery.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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