This part is a kind of semiconductor called LRD01.

Function of this product has 3-pole Thermal Overload Relays.

Manufacturers : Schneider

Image and pinout :

Some of the text within the PDF file :

www.schneider-electric.com LRD 01...35 3-pole Thermal Overload Relays Use in Explosive Atmospheres e 0080 II (2) GD - Zones 1 - 2, 21 - 22 EC type examination certificate: INERIS 06ATEX0036X Description LRD01 to LRD35 3-pole thermal overload relays are designed to protect a.c. circuits and motors against overloads, phase failure, long starting times and prolonged stalling of the motor. 1 Adjustment dial Ir. 2 Test button. Operation of the Test button allows: - checking of control circuit wiring, - simulation of relay tripping (actuates both the N/O and N/C contacts). 3 Stop button. Actuates the N/C contact; does not affect the N/O contact. 4 Reset button. 5 Trip indicator. 6 Setting locked by sealing the cover. 7 Selector for manual or automatic reset. Relays LRD 01 to 35 are supplied [ ... ]

LRD01 PDF Datasheet Download