Thermal Overload Relay Engineering Guide
A senior-engineer guide to thermal overload relays: bimetallic vs electronic construction, trip classes, FLC dial setting, star-delta sizing, phase-loss and ambient compensation, reset modes,...
- Part number
- LR97D38B
- Model no
- LR97
- UL
- CSA
Schneider Electric LR97D38B TeSys D Electronic Overload Relay 20-38 A 24 V AC/DC LC1D Relay
TeSys D electronic overcurrent relay, 20-38 A, 24 V AC/DC supply, for LC1D25...D38.
Description
About the LR97
About the LR97
The Schneider Electric LR97D38B is a TeSys LR97D electronic overcurrent relay for direct mounting under a LC1D25...D38 contactor, adjustable over 20-38 A on its LOAD dial with a 20-34 A tripping threshold. It is supplied from 24 V AC/DC and adds adjustable O-TIME and D-TIME dials plus phase-failure detection that a plain bimetallic relay cannot match.
Certifications & Standards
- GOST
- CSA
- UL
- IEC 60947
- IEC 60255-6
Selection Notes
The 20-38 A LOAD dial covers LC1D25...D38 contactors; set it to the motor's actual full-load current rather than the top of the range so the 20-34 A tripping threshold protects the winding instead of the contactor's maximum rating. The D-TIME dial (0.5-30 s) should match the motor's real starting time so the relay rides through inrush without nuisance tripping, while O-TIME (0.3-10 s) sets how long a steady-state overcurrent above 3×LOAD is tolerated before the relay opens its 1 C/O contact. Pick the 24 V AC/DC variant to match the control transformer already feeding the rest of the panel; the current-setting dials are identical across every supply-voltage variant in this range.
Specification
Full specification
Main 10
| Device short name | LR97 |
|---|---|
| Product or component type | Electronic overcurrent relay |
| Device application | Protection |
| Relay application | Sensitivity to phase failure, Overload Imax > Isetting, Locked rotor, mechanical jamming I > 3 x Isetting |
| Product compatibility | LC1D25...D38 |
| Network type | DC, AC |
| [Us] rated supply voltage | 24 V AC/DC |
| Thermal protection adjustment range | 20…38 A |
| [Ue] rated operational voltage | 600 V AC 50/60 Hz for power circuit conforming to CSA, 600 V AC 50/60 Hz for power circuit conforming to UL, 690 V AC 50/60 Hz for power circuit conforming to IEC 60947-4-1 |
| Quantity per set | Set of 10 |
Complementary 20
| Network frequency | 50...60 Hz |
|---|---|
| Mounting support | Direct on contactor, Rail |
| Tripping threshold | 20...34 A |
| Surge withstand | 6 kV conforming to IEC 61000-4-5 |
| Contacts type and composition | 1 C/O |
| [Ith] conventional free air thermal current | 3 A for control circuit |
| Protection type | BS fuse 3 A - for control circuit, GB2 circuit breaker 3 A - for control circuit, GG fuse 3 A - for control circuit |
| Maximum power | 28 W at 110 V DC conforming to IEC 60947, 28 W at 220 V DC conforming to IEC 60947, 55 W at 24 V DC conforming to IEC 60947, 55 W at 48 V DC conforming to IEC 60947, 140 VA at 48 V AC conforming to IEC 60947, 360 VA at 110 V AC conforming to IEC 60947, 360 VA at 220 V AC conforming to IEC 60947, 70 VA at 24 V AC conforming to IEC 60947 |
| [Ui] rated insulation voltage | Power circuit: 600 V conforming to CSA, Power circuit: 600 V conforming to UL, Power circuit: 690 V conforming to IEC 60947-4-1 |
| [Uimp] rated impulse withstand voltage | 6 kV |
| Phase failure sensitivity | < 3 s |
| Reset | Automatic reset 120 s fixed, Electrical by interruption of power supply for minimum 0.1 s, Manual reset |
| Time range | 0.2...10 s - O-time knob, 0.3...10 s - O-time knob, 0.5..30 s - D-time knob |
| Signalling function | 2 LEDs |
| Connections - terminals | Control circuit: cable 1 x 1…25 mm²flexible with cable end, Control circuit: cable 1 x 1…25 mm²flexible without cable end, Control circuit: cable 2 x 1…25 mm²flexible without cable end, Control circuit: lug-clamp 1 x 1…25 mm²flexible with cable end, Control circuit: lug-clamp 1 x 1…25 mm²flexible without cable end, Control circuit: lug-clamp 2 x 1…25 mm²flexible with cable end, Control circuit: lug-clamp 2 x 1…25 mm²flexible without cable end, Control circuit: cable 2 x 1…25 mm², Power circuit: cable 1 x 1…6 mm²flexible without cable end, Power circuit: cable 1 x 2.5…10 mm²flexible with cable end, Power circuit: lug-clamp 1 x 1…6 mm²flexible without cable end, Power circuit: lug-clamp 1 x 2.5…10 mm²flexible with cable end |
| Tightening torque | Control circuit: 0.6...1.2 N.m on lug-clamp, Power circuit: 2 N.m on cable |
| Height | 67.5 mm |
| Width | 45 mm |
| Depth | 67.5 mm |
| Net weight | 0.172 kg |
Environment 15
| Standards | IEC 60255-6, IEC 60947 |
|---|---|
| Product certifications | CSA, UL, GOST |
| Protective treatment | TH conforming to IEC 60068 |
| IP degree of protection | IP20 conforming to IEC 60529 |
| Ambient air temperature for operation | -25…60 °C conforming to IEC 60947-4-1 |
| Ambient air temperature for storage | -30…80 °C |
| Operating altitude | 2000 m |
| Fire resistance | 850 °C conforming to IEC 60695-2-1 |
| Shock resistance | 15 gn 11 ms conforming to IEC 60068-2-7 |
| Vibration resistance | 4 gn conforming to IEC 60068-2-6 |
| Dielectric strength | 2 V 50 Hz conforming to IEC 60255-5 |
| Resistance to electrostatic discharge | 6 kV in indirect mode, 8 kV in air |
| Resistance to radiated fields | 10 V/m level 3 |
| Resistance to fast transients | 2 kV |
| Disturbance radiated/conducted | 10 V conforming to EN 61000-4-6, Class A conforming to EN 55011 |
Show all 69 specifications ↓ Show less ↑24 more values in Identification, Contractual warranty, Logistics.
Identification 7
| Part number | LR97D38B |
|---|---|
| Type designation | LR97 |
| Brand | Schneider Electric |
| Condition | New, factory sealed |
| Source | Schneider Electric and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Active, in production |
Contractual warranty 1
| Warranty (in months) | 18 |
|---|
Logistics 16
| Unit Type of Package 1 | PCE |
|---|---|
| Number of Units in Package 1 | 1 |
| Package 1 Height | 5.300 cm |
| Package 1 Width | 7.000 cm |
| Package 1 Length | 7.700 cm |
| Package 1 Weight | 173.000 g |
| Unit Type of Package 2 | S02 |
| Number of Units in Package 2 | 24 |
| Package 2 Height | 15.000 cm |
| Package 2 Width | 30.000 cm |
| Package 2 Length | 40.000 cm |
| Package 2 Weight | 4.637 kg |
| Shipping weight | 0.172 kg |
| Ships from | Türkiye |
| Dispatch | — |
| Stock | On request |
Source: manufacturer data · Last verified: 30 Oct 2026
Documents
Documents for LR97D38B 3
-
Datasheet
ProductDownload PDF: Product data sheet LR97D38B
Product data sheet LR97D38B
-
Manual
ProductDownload PDF: Instruction sheet 1636662_01A55
Instruction sheet 1636662_01A55
-
Certificate
ProductDownload PDF: Environmental Disclosure ENVPEP2505001EN
Environmental Disclosure ENVPEP2505001EN
Certifications
Certifications and standards
- UL
- CSA
- IEC 60255-6
- IEC 60947
Quick answers
Questions about the LR97
What is the rated current of LR97?
The rated current of LR97 is 38 A.
Which supply voltage is LR97 rated for?
The rated operational voltage of LR97 is 24–DC V DC.
What is the HS code of LR97 for customs?
The tariff (HS) code on file for LR97 is 85364900.
Where does LR97 ship from, and how fast?
LR97 ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival.
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