LRD3357 | TeSys LRD thermal overload relays – 37…50 A – class 10A – Schneider Electric

Name: TeSys LRD3357 Overload Relay - 37-50A, Class 10A
Brand: Schneider Electric
SKU: LRD3357
Price: 6531.75 INR
Availability: InStock

SKU: LRD3357

Original price was: ₹14,515.00.Current price is: ₹6,531.75. Excl. GST

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The Schneider Electric LRD3357 is an overload relay from the TeSys range, engineered for motor control and switching in demanding Indian and international installations. Key ratings include 37–50 A, 1000 V AC 0…400 Hz for power circuit, IP20. Buy the LRD3357 | TeSys LRD thermal overload relays – 37…50 A – class 10A online at myelectric.in with GST invoice, genuine-product assurance, and fast delivery across India — bulk and worldwide export enquiries welcome.

📋 Technical Specifications

Product
Brand	Schneider Electric
Part Number / SKU	LRD3357
Category	Overload Relay
Main
Range	TeSys
Product name	TeSys LRD TeSys Deca
Product or component type	Differential thermal overload relay
Device short name	LRD
Relay application	Motor protection
Product compatibility	LC1D95 LC1D80
Network type	DC AC
Thermal overload class	Class 10A conforming to IEC 60947-4-1
Thermal protection adjustment range	37…50 A
[Ui] rated insulation voltage	Power circuit: 1000 V conforming to IEC 60947-4-1 Power circuit: 600 V conforming to CSA Power circuit: 600 V conforming to UL
Complementary
Network frequency	0…400 Hz
Mounting support	Plate, with specific accessories Rail, with specific accessories Under contactor
Tripping threshold	1.14 +/- 0.06 Ir conforming to IEC 60947-4-1
Auxiliary contact composition	1 NO + 1 NC
[Ith] conventional free air thermal current	5 A for signalling circuit
Permissible current	0.72 A at 500 V AC-15 for signalling circuit 0.06 A at 440 V DC-13 for signalling circuit
[Ue] rated operational voltage	1000 V AC 0…400 Hz for power circuit conforming to IEC 60947-4-1
Associated fuse rating	4 A gG for signalling circuit 4 A BS for signalling circuit
[Uimp] rated impulse withstand voltage	6 kV conforming to IEC 60947-1
Phase failure sensitivity	Tripping current 130 % of Ir on two phase, the last one at 0
Control type	Red push-button: stop Blue push-button: reset
Temperature compensation	-20…60 °C
Connections – terminals	Power circuit: screw clamp terminals 1 cable(s) 4…35 mm² flexible without cable end Power circuit: screw clamp terminals 1 cable(s) 4…35 mm² flexible with cable end Power circuit: screw clamp terminals 1 cable(s) 4…35 mm² solid without cable end Control circuit: screw clamp terminals 2 cable(s) 1…2.5 mm² flexible without cable end Control circuit: screw clamp terminals 2 cable(s) 1…2.5 mm² flexible with cable end Control circuit: screw clamp terminals 2 cable(s) 1…2.5 mm² solid without cable end
Tightening torque	Control circuit: 1.7 N.m – on screw clamp terminals Power circuit: 9 N.m – on screw clamp terminals
Height	81 mm
Width	70 mm
Depth	115 mm
Product weight	0.51 kg
Environment
Climatic withstand	conforming to IACS E10
IP degree of protection	IP20 conforming to IEC 60529
Ambient air temperature for operation	-20…60 °C without derating conforming to IEC 60947-4-1
Ambient air temperature for storage	-60…70 °C
Flame retardance	V1 conforming to UL 94
Mechanical robustness	Vibrations: 6 Gn conforming to IEC 60068-2-6 Shocks: 15 Gn for 11 ms conforming to IEC 60068-2-7
Dielectric strength	2.2 kV at 50 Hz conforming to IEC 60947-1
Standards	EN/IEC 60947-4-1 EN/IEC 60947-5-1 UL 60947-4-1 UL 60947-5-1 CSA C22.2 No 60947-4-1 CSA C22.2 No 60947-5-1 GB/T 14048.4 GB/T 14048.5 EN 50495
Product certifications	IEC UL CSA CCC EAC ATEX INERIS UKCA
Packing Units
Unit Type of Package 1	PCE
Number of Units in Package 1	1
Package 1 Height	8.000 cm
Package 1 Width	12.000 cm
Package 1 Length	8.700 cm
Package 1 Weight	492.000 g
Unit Type of Package 2	S02
Number of Units in Package 2	12
Package 2 Height	15.000 cm
Package 2 Width	30.000 cm
Package 2 Length	40.000 cm
Package 2 Weight	6.203 kg
Unit Type of Package 3	P06
Number of Units in Package 3	192
Package 3 Height	75.000 cm
Package 3 Width	60.000 cm
Package 3 Length	80.000 cm
Package 3 Weight	110.628 kg
Contractual warranty
Warranty (in months)	18

⚡ Key Features

Adjustable current range 37–50 A — set to the motor nameplate FLC for accurate overload detection; range covers multiple motor sizes from a single relay model.
Class 10A trip class — trips within 10 seconds at 7.2× FLC; standard for normal-start motors (fans, pumps, compressors) where starting time is under 10 seconds.
Bimetal thermal element with phase-loss sensitivity — independently monitors each phase; trips if any phase carries more than ~115% of the set current, or on complete phase failure.
Normally open (NO) and normally closed (NC) auxiliary contacts built in — NO contact wired to motor run indicator; NC contact wired to PLC fault input or motor starter stop circuit.
Direct clip-on mounting to TeSys LC1 contactors — no external wiring between overload and contactor; forms a complete IEC 60947-4-1 DOL motor starter combination.
Manual/automatic reset selectable — set to manual for attended machinery requiring operator acknowledgement; auto-reset for unattended remote installations.
Manufactured to IEC 60947-4-1 / IS 13947-4-1 — complies with the applicable Indian BIS and IEC international standards for this product category.
BIS certified, CE marked, RoHS compliant — meets Indian regulatory requirements for use in government, commercial, and industrial electrical installations.
Genuine authorised Schneider Electric product — sourced directly from the official distribution network with full manufacturer traceability and warranty.
GST invoice provided for India orders — valid for corporate procurement, government project orders, and public tender supply via myelectric.in.

🔗 Compatible Products & Accessories

The following genuine accessories and compatible devices are designed to work with this product. Contact myelectric.in for pricing and availability:

LA7D305LA7D902XB5AL84101XB5AA86102LA7D03FLA7D03M

❓ Frequently Asked Questions

Q: How do I set the 37–50 A adjustable range on the LRD3357 for my motor?

A: Turn the setting dial to the motor’s nameplate full-load current (FLC) — the FLC must fall within the 37–50 A range of this device. Setting it at the motor FLC (not the maximum of the range) gives correct overload trip timing while still riding through normal starting inrush. If the motor FLC is outside this range, select the adjacent rating in the same series.

Q: How do I set the LRD3357 to protect a motor without causing nuisance trips on starting?

A: Set the thermal overload dial to the motor’s nameplate full-load current (FLC) — ensure the FLC is within the 37–50 A range of this relay. For star-delta starters, set the overload relay to 58% of motor FLC (line current in delta = FLC × 0.58). Allow 10 trips for the relay’s thermal memory to stabilise before adjusting the setting.

Q: Does the LRD3357 provide single-phase (phase loss) protection?

A: Schneider Electric thermal overload relays include single-phase sensitivity: if one phase is lost, the remaining phases carry higher current, causing the bimetal to heat and trip within the specified time. For critical motors, add a dedicated phase-loss relay for faster response independent of load — overload relay phase-loss protection is load-dependent and may take minutes to trip at light load.

Q: What is the difference between an Overload Relay and a standard MCB — and why use the LRD3357?

A: A standard MCB protects against overload and short-circuit only. An Overload Relay provides thermal overload protection calibrated to motor FLC, protecting the motor from sustained overloads that would destroy windings before a standard MCB trips. Choose the LRD3357 when the application specifically requires overload relay characteristics.