LR2D3561

What does this thermal overload relay do in a motor starter?

It provides motor overload and phase-loss protection by monitoring current through the motor and tripping when an overload condition is detected, helping to prevent overheating damage. This device is a differential thermal overload relay (LR2D3561).

What current range can the relay be set to?

The adjustable thermal protection setting range is 55 to 70 A, allowing you to match the trip setting to the motor’s rated current.

What trip class is it and what does that mean?

It is Class 20 (IEC 60947-4-1), which is typically selected for motors with higher starting times or heavier starting loads where a longer permissible start duration is required compared with faster trip classes.

Which contactors is it designed to work with?

It is specified as compatible with LC1D80 and LC1D95 contactors, commonly used in TeSys D motor starter assemblies.

Can it be used on AC or DC systems?

Yes. It is designed for AC and DC network types, making it suitable for a wide range of motor control panels.

What frequency range is supported?

It supports 0 to 400 Hz, which covers standard mains applications and many variable-frequency drive (VFD) output scenarios.

How sensitive is it to phase failure on three-phase motors?

It includes phase failure sensitivity: it trips when two phases carry approximately 130% of the set current (Ir) while the remaining phase is at 0, helping protect the motor during single-phasing conditions.

What auxiliary contacts are included for control signalling?

It includes 1 normally open (NO) and 1 normally closed (NC) auxiliary contact for status indication and interlocking in control circuits.

What are the signalling contact ratings for typical control duties?

For signalling circuits, permissible current is 0.72 A at 500 V AC-15 and 0.06 A at 440 V DC-13. The conventional free-air thermal current (Ith) for the signalling circuit is 5 A.

What are the main voltage ratings to consider when selecting it?

Key ratings include: rated insulation voltage (Ui) up to 690 V (IEC) for the power circuit, and an impulse withstand voltage (Uimp) of 6 kV. The rated operational voltage (Ue) for the power circuit is specified up to 1000 V AC (0–400 Hz) in the latest product data.

How is it mounted in a panel?

It can be mounted under a compatible contactor, or on a plate or rail when used with the appropriate accessories, giving flexibility for motor control panel layouts.

What cable sizes can be terminated on the power and control terminals?

Power circuit screw clamp terminals accept 4 to 35 mm² (solid or flexible, with or without cable end). Control circuit screw clamp terminals accept 1 to 2.5 mm² (solid or flexible, with or without cable end).

What tightening torque should be used for the terminals?

Typical tightening torques are 9 N·m for the power terminals and 1.7 N·m for the control terminals.

What are the dimensions and approximate weight?

Approximate dimensions are 100 mm (H) × 75 mm (W) × 121 mm (D), with a net weight around 0.535 kg.

What environmental limits should be considered in a control cabinet?

It is rated for operation from -20 to +60 °C without derating and storage from -60 to +70 °C. The ingress protection rating is IP20, so it is intended for installation inside an appropriate enclosure.