Flat, laminated “stick” RTDs fit in slots between stator windings to monitor temperature rise and prevent overheating. The National Electrical Manufacturers Association (NEMA) recognizes embedded detectors as a standard protection for motor and generator insulation. Unlike on-off devices, RTDs provide continuous sensing for earlier warning without unnecessary trip outs.

Minco stator RTDs meet the specification of ANSI C50.10-1990, general requirements for synchronous motors. Six sensors are recommended for each motor, two per phase. Locating the sensors near the hottest point of the windings will provide the best performance.

Minco’s lamination capabilities enable endless possibilities for design configurations. The laminated design provides a completely sealed sensor to improve resistance to VPI processing and withstand harsh installation and operating conditions.

  • Straight Lead Exit: Designed to embed at various positions within the length of the stator slot.
  • Side Lead Exit: Designed to overhang the end turns for easy lead wire routing
  • Paddle Sensors: Designed for Air/Gas temperature installation

Minco manufactures the complete laminated stator sensor, enabling a broad range of profiles, sizes, and dimensions. The table below indicates a few of the industry standard dimensions and Minco capabilities.

Standard(s) Maximum
inches (mm)
 0.030 (0.76)

 0.030 (.76)
 0.050 (1.3)
 0.078 (2.0)
 0.125 (3.2)

 Greater than 0.350 (8.9 mm)

inches (mm)

 0.70 (17.8)
 2.0 (50.8)
 6.0 (152)
 11.0 (279)
 20.0 (508)
 Greater than 18 ft (5.5 meters)
inches (mm)
 0.219 (5.6)
 0.219 (5.6)
 0.305 (7.7)
 0.344 (8.7)
 0.425 (10.8)
 Greater than 2.0 (50.8)

Minco’s fine wire handling and advanced processing capabilities enable custom manufacture and supply of sensors that are compatible with a large variety of instrumentation requirements. Dual sensing element designs are available for redundancy and to reduce the space and number of slots that need to be allocated for temperature sensors.

  • Averaging (Wire-Wound): The sensing elements of wire-wound RTDs extend through most of the body length to provide an average temperature reading. This enables better detection of localized hot spots within the stator windings.
    • Platinum Resistance Temperature Detectors (RTD) include a wide range of TCRs
      • Range from 0.00375 to 0.003927 Ω/Ω/°C
      • 0.00385 Ω/Ω/°C (Minco element "PD") is the most popular industry standard
    • Nickel, copper, and nickel-iron RTD elements
    • Non-standard resistance-temperature curves
    • Base resistances up to thousands of ohms
  • Point Sensing:
    • Thermistor temperature sensors (PTC or NTC)
    • Thermocouple temperature sensors

The most common industry standard element options are listed below.

   Minco Code
 NA  0.00672 Ω/Ω/°C  120 Ω @ 0°C
 Copper  CA  0.00427 Ω/Ω/°C  10 Ω @ 25°C
 Platinum  PA  0.00392 Ω/Ω/°C  100 Ω @ 0°C
 PE  0.00385 Ω/Ω/°C  100 Ω @ 0°C
 PD  0.00385 Ω/Ω/°C  100 Ω @ 0°C
 ±0.12% Meets EN60751, Class B
 PM  0.00385 Ω/Ω/°C  100 Ω @ 0°C
 ±0.06% Meets EN60751, Class A

  • Temperature Limit: Minco uses high temperature insulation, with ratings suitable for both Class F (155C) and Class H (180C) applications.
  • Accuracy: Minco offers high accuracy capability, including Class A at ±0.15°C, supported by measurement systems that are fully traceable to the National Institute of Standards and Technologies (NIST).
  • Dielectric Strength: Industry standard designs are capable of meeting 3,200 VRMS at 60 Hz. Increased design options are suitable to meet 5,000 VRMS at 60Hz. For variable speed drive applications, where PWM inverters can create high voltage spikes exceeding 1600 volts, Minco has developed a Corona resistant technology capable of meeting 10,000 VAC without failure.
  • Lead Wire: Minco uses specialty lead wire manufacturing techniques to maximize the lead pull strength for rigorous handling and VPI requirements. PTFE insulation is commonly used for high temperature and chemical resistance properties. Other lead wire coverings are available, including metal braid to reduce electrical noise and jackets or sleeving for added abrasion protection.

See Minco’s Technical Brochure for complete information.

To learn more about our products, please visit our online catalog.

Product Certifications

Minco has experience with many different regulatory agencies and can adjust design specifications to meet these stringent requirements for safety, EMC, and explosive atmospheres. Minco's product-level certifications for stator sensor products include:

  • Increased Safety (Zone 1):
    • ATEX II 2 G Ex e IIC Gb
    • IECEx Ex e IIC Gb
    • CSA Ex e IIC Gb
  • Intrinsic Safety (Zone 0):
    • ATEX II 1 G Ex ia IIC T6…T3 Ga
    • IECEx Ex ia IIC T6…T3 Ga

All of Minco's product specific certifications can be found in the resource library under Certifications.


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