Multispan WTR-35 Winding Temperature Relay | PTC Thermistor Input | Auto/Manual Reset

Product Summary:

The Multispan WTR-35 is an industrial-grade winding temperature relay that monitors motor or transformer winding temperature via PTC thermistors. It provides fail-safe or non-fail-safe operation, fast trip response, LED status indication, and supports auto, manual, and remote reset modes. With a wide auxiliary supply range and DIN rail mount design, it's a perfect fit for thermal protection in motor control centers and electrical panels.

🔹 Key Features:

• Input Sensor: PTC Thermistor (single or series connected)

• Sensor Range: 70°C to 180°C NRT

• Trip Resistance Threshold: ≥ 4KΩ (typical)

• Reset Options: Auto / Manual / Remote

• Auxiliary Supply: 50–550V AC, 50/60Hz

• Relay Output: 1 Relay, 2 Changeover (2CO)

• Contact Rating: 5A @ 230V AC resistive

• Trip Time Delay: Less than 1 second

• LED Indications: Sensor Short, Healthy, Trip

• Mounting Type: 35 mm DIN Rail

• Enclosure: ABS / PC-ABS

• Dimensions: 90 x 35 x 61.5 mm

• Operating Temp: -5°C to +60°C

• Humidity: Up to 95% RH non-condensing

• Fail-Safe & Non-Fail-Safe selectable
  

🔹 Applications:

• 3-phase induction motors

• Dry type transformers

• Gear motors and pump panels

• HVAC & compressor units

• Industrial automation panels

• Over-temperature alarm systems
  

🔹 Product Benefits:

• Reliable Motor Protection: Prevents thermal damage from over-temperature

• Quick Response: Trips in under 1 second after sensor resistance exceeds threshold

• Flexible Reset Options: Auto, manual (on-device), or remote button

• DIN Rail Ready: Easy to install in standard control panels

• Universal AC Input: Accepts 50–550V AC without additional adaptors

• Fail-Safe Logic: Maintains operational safety in case of power or sensor fault
  

❓ FAQs:

Q1. What type of thermistor is supported?
It supports Positive Temperature Coefficient (PTC) thermistors with NRT between 70°C and 180°C.

Q2. How does the relay behave on sensor fault?
It trips when resistance exceeds 4KΩ, and indicates fault using LED signals.

Q3. Is it possible to reset remotely?
Yes, you can reset via an external push button or via the manual front button.

Q4. Can I use multiple thermistors in series?
Yes, up to 3 thermistors can be connected in series, provided total loop resistance does not exceed 1.65KΩ at 25°C.

Q5. How does the fail-safe mode work?
In fail-safe mode, the relay remains ON in healthy condition and trips during faults or power failure.