What is embedded stator RTD temperature monitoring?

Embedded temperature monitoring of motors and generators is a long-time industry-accepted practice, allowing for continuous assessment of equipment conditions. The embedded method utilizes specially designed Resistance Temperature Detectors (RTDs) and Thermocouples placed outside the major insulation as specified in ANSI C50-10-1990, with the sensing element of RTDs placed in the stator winding slots.

What are the benefits of using embedded RTDs for stator temperature monitoring?

Benefits include accuracy of temperature measurement across a greater area of the stator, extreme responsiveness to temperature change, elimination of problems with “tip sensors,” the ability to be made to various lengths to meet customer needs, and robust construction for direct installation between windings.

What materials are used for embedding RTDs in stator windings?

The RTD can be embedded in either NEMA G-11 or The Gund Company’s Semi-Conductive materials, which provide mechanical protection and, in the case of the semi-conductive material, the added benefit of corona dissipation.

What are flexible RTDs and how are they used?

Flexible RTDs are surface mount silicone resistance temperature detectors for direct mounting to flat or curved surfaces. They can be custom manufactured in various thicknesses and supplied with adhesive backing for quick application. Other carriers, such as Polyimide, can also be supplied.

What is a bearing RTD and how does it function?

Bearing RTDs are used in the monitoring of the temperature of shaft bearings and their oil lubricants in rotational equipment. They consist of a probe or sensor attached either directly or through a probe holder and a probe head that allows for connection to the equipment’s monitoring system.

RTDs

Q: What is a GTH RTD and where is it used?

GTH Stator RTDs are custom embedded RTDs designed for the Turbo Generator and Hydro Generator marketplace. This standard product is a dual-element platinum RTD with a 40-foot shielded cable, available for sale individually or embedded in G-11 or Semi-Conductive composite materials.

Q: What are embeddable bearing RTDs and why are they important?

Embeddable bearing RTDs and thermocouples are designed for environments where size and space are restricted and can be installed in tight areas within the bearing housing. These sensors provide a direct measurement of the bearing’s temperature, allowing for early detection of potential issues such as overheating, which can lead to bearing failure.

Q: What options are available for RTD wires and cables?

RTD wires use standard AWG wires to create custom specified color codes, coatings, and shielding. All stocked RTDs will have available spools of matching cables for splicing longer distances, and The Gund Company can manufacture wires to match another manufacturer’s RTD cable.

Embedded Stator RTD

Embedded temperature monitoring of motors and generators is a long-time industry-accepted practice, allowing for continuous assessment of equipment conditions. The embedded method of monitoring utilizes specially designed Resistance Temperature Detectors (RTDs) and Thermocouples (T/Cs) placed outside the major insulation as specified in ANSI C50-10-1990, The sensing element of RTDs are placed in the stator winding slots. The longer length of the RTD sensors element designs allows for averaging the measurement process over a greater portion of the slot length. This eliminates the problems related to tip-sensitive sensors that can be misleading when “hot spots” are present. Since stator RTD sensors sometimes exceed 20 inches in body length, this is a useful characteristic the RTD brings to monitoring the health of your generator.

RTD Benefits

The accuracy of temperature measurement across a greater area of the stator.
Extremely responsive to temperature change.
RTD lengths eliminate problems with “tip sensors.”
It can be made to various lengths to meet the customer’s needs.
Robust to be directly installed between windings

RTD Testing

RTDs can be tested upon request up to 3000 VRMS @60Hz for 1 minute between lead wire and enclosure body.

RTD Embedding Materials

The RTD can be embedded in either NEMA G-11 or The Gund Company’s Semi-Conductive materials up to 109 inches for installation into the stator of your application. NEMA G-11 provides mechanical protection for the RTD during the installation phase and protects the RTD throughout its life span. The Semi-Conductive material provides the same mechanical protection with the added benefit of corona dissipation.

RTD Literature

Stator RTD

All five rows of the chart below maintain these identical charecteristics:

Class H Rating
15-foot Lead Wire Length
26 AWG Lead Wire Gauge
PTFE Lead Wire Coating

Properties Per Part ID
Part ID	Dimensions	Element	Resistance	No. of Elements	No. of Wires
RTD1A2540.7626.6P3457226PTS	10″L x 0.260″W x 0.030″T	Platinum	100 Ωm ± 0.5% @ 0°C	1	3
RTD1A2540.7626.6C3457226PTS	10″L x 0.260″W x 0.030″T	Copper	10 Ωm ± 0.5% @ 0°C	1	3
RTD1A2540.7626.6N3457226PTS	10″L x 0.260″W x 0.030″T	Nickel	120 Ωm ± 0.5% @ 0°C	1	3
RTD2A3050.76213.2P3457226PTS	12″L x 0.520″W x 0.030″T	Platinum	100 Ωm ± 0.5% @ 0°C	2	6
RTD2A4570.76213.2P3457226PTS	18″L x 0.520″W x 0.030″T	Platinum	100 Ωm ± 0.5% @ 0°C	2	6

Properties
Element Type	Base Resistance	TCR (Ohm/Ohm/°C)
Platinum	100	0.00385
Nickel	120	0.00672
Copper	10	0.00427

Embedded Stator (RTDs)

Enclosure types include G-11 and Semi-Conductive rigid enclosure of the elements.

GTH RTD – Designed Specifically for use in Turbo Generators and Hydro Generators
GTH Stator RTDs are “custom” embedded RTDs designed for the Turbo Generator and Hydro Generator marketplace. This standard product is a dual-element platinum RTD with a 40-foot shielded cable. These parts are available for sale individually or can be embedded in G-11 or semi-conductive composite materials.

The item in the chart below maintains these characteristics:

Class H Rating
40-foot Lead Wire Length
22 AWG Lead Wire Gauge
PTFE/Shielded Lead Wire Coating

Properties Per Part ID
Part ID	Dimensions	Element	Resistance	No. of Elements	No. of Wires
RTD2A4570.76213.46P412395222RT	18”L x 0.530W x 0.030T	Platinum	100 Ωm ± 0.5% @ 0°C	2	4

Properties
Element Type	Base Resistance	TCR (Ohm/Ohm/°C)
Platinum	100	0.00385
Nickel	120	0.00672
Copper	10	0.00427

Flexible RTDs

Utilizing the similar technology for the stator RTDs, The Gund Company now offers surface mount silicone resistance temperature detectors for direct mounting to flat or curved surfaces. These flexible RTD temperature sensor design can be custom manufactured in various thicknesses and supplied with an adhesive backing for quick application. Additionally, other “carries” can be supplied such as a Polyimide carrier in the same configuration as the current silicone RTD.

All five rows of the chart below maintain these identical charecteristics:

Class H Rating
15-foot Lead Wire Length
1 Element
3 Wires
26 AWG Lead Wire Gauge
PTFE Lead Wire Coating

Properties Per Part ID
Part ID	Dimensions	Coating	Resistance	Element
RTDFA31.750.76212.7C3457226PFT	1.20″L x 0.50″W x 0.03″T	Polyimide	10 Ωm ± 0.5% @ 0°C	Copper
RTDFA31.750.76212.7P3457226PFT	1.20″L x 0.50″W x 0.03″T	Polyimide	100 Ωm ± 0.5% @ 0°C	Platinum
RTDFA511.659.5C3243826PTT	2.00″L x 0.375″W x 0.125″T	Silicone	10 Ωm ± 0.5% @ 0°C	Copper
RTDFA511.659.5N3243826PTT	2.00″L x 0.375″W x 0.125″T	Silicone	120 Ωm ± 0.5% @ 0°C	Nickel
RTDFA511.659.5P3243826PTT	2.00″L x 0.375″W x 0.125″T	Silicone	100 Ωm ± 0.5% @ 0°C	Platinum

Embeddable Bearing RTDs and Thermocouples

Designed for environments where size and space are restricted, Embeddable Bearing Sensors can be installed in tight areas within the bearing housing. These sensors provide a direct measurement of the bearing’s temperature, allowing for early detection of potential issues such as overheating, which can lead to bearing failure. By identifying potential failures early, timely maintenance can be performed, helping to prevent costly downtime.

Bearing RTDs

Bearing RTDs are used in the monitoring of the temperature of shaft bearing and their oil lubricants. Bearings are used in rotational equipment from motors, blowers, fans and generators. Critical monitoring of the bearing temperature can give indication of excessive wear or friction which can lead to increased temperature and premature or even catastrophic failure of the equipment.

Bearing RTD consist of a probe or sensor that is attached either directly or through a probe holder and a probe head that is allows for the connection of the RTD to the equipment’s monitoring system.

Wire RTDs

RTD wires use standard AWG wires to create the custom specified color codes, coatings and shielding you the customer require. All Stocked RTDs will have available spools of matching cables for when you need to splice for longer distances. Also, we manufacture these wires and cables. This allows TGC to service our customers even if they need wires made to match another manufacturers RTD cable.