Siemens 3TH4040-0B Contactor

Siemens 3TH4040-0B Contactor Relay is a Siemens-manufactured control-relay component from the 3TH4 family, built to switch higher-power loads in industrial control panels and automation systems. As part of Siemens' legacy contactor line, the 3TH4040-0B provides a modular solution for motor-start and power-switching applications where reliable relay operation is required in combination with other Siemens controls. Authorized distributors list the item by its exact model number, confirming it as a genuine Siemens spare part suitable for maintenance, replacement, or integration with existing 3TH4-based installations. This model is used in settings that require robust, field-replaceable contactor-relay functionality within standard control circuits, and it is compatible with the broader Siemens Sirius IC10-era catalog of control-relay components.